Wednesday, August 29, 2007

Energy-generation: Dream source.

This is the last of these expository posts in the series. Next week, I'll put up my final evaluation of the various energy sources that I've considered. However, this week, I wanted to take a look at a possible energy source that has been talked about, it seems to me, for years, yet has never really gone anywhere. I'm referring to nuclear fusion.

Fusion reactors produce energy by fusing two light atomic nuclei into a heavier one. The idea is that bringing the two nuclei together will allow the strong nuclear force in the nuclei to pull them together into a larger atom; as this new atom has slightly less mass than the sum of the original two masses, the difference is released as energy according to good ol' E = mc2. However, if the input atoms are heavier than iron, then the output atom will be heavier than the total mass of the inputs; in this case, then, the reaction will actually consume energy rather than release it.

The trick, though, is that input atoms also have an electrostatic force -- the net positive charge of the nuclei. In order to overcome it so that the atoms can combine, energy needs to be introduced into the process. The easiest way to do this, according to Wikipedia at any rate, is to heat the atoms, usually to the point at which they become plasma. The temperature that must be reached is a function of the total charge, thus hydrogen reacts at the lowest temperature; since helium has a very low mass per nucleon (i.e., nuclear particle, a proton or neutron), it tends to be the product.

Perhaps the easiest way to harness this for electricity generation is as part of a thermal power plant, of which I have discussed several types already. The process is, again, to use heat to heat/boil water (or some other substance), then drive a turbine, which drives a generator, which produces electricity.

There are a few technical challenges facing fusion as a source of commercial electricity. The first is related to the choice of fuel. One model (D-T) takes deuterium and tritium as inputs to produce helium-4 and a neutron. Since finding tritium is quite tricky (although deuterium is not), it must be bred from lithium and a neutron. So, the cycle here is obvious: D and T produce He-4 and n; n and either Li-6 or Li-7 produce T and He-4 (and, in the case of Li-7, another n). Due to the prevalence of neutrons in these reactions, though, D-T fusion results in induced radioactivity (i.e., the absorption of neutrons by the reactor structure, creating radioactive materials). (It should be noted, though, that it might be possible to convert this radiation directly into electricity, rather than trying to transport the reactor's power by some other means.) Along the same lines, the use of tritium can be a problem, as tritium is hard to contain; thus some radiation would leak into the environment. Furthermore, lithium supplies are limited, so this form of fusion would not last forever. Finally, only about 20% of the energy output is in the form of charged particles, which basically forces the reactor to be used as part of a thermal power plant. (The relative lack of charged particles means, as I understand it, that little energy can be harvested directly from the reaction.) Another (D-D) model combines two deuterium atoms to produce, with equal probability, tritium and a proton or helium-3 and a neutron. This model, then, has a similar problem with tritium as the D-T model; and, if the tritium is burned before leaving the reactor, it will produce more neutrons, resulting in the problem of induced radioactivity again. Furthermore, the energy confinement must be significantly better, and less power is produced by the reactor. The basic advantage, though, is that the reactor doesn't require tritium breeding nor the use of lithium.

The second is related to confinement. Creating uncontrolled fusion reactions isn't that hard -- they're called hydrogen bombs. Suffice to say, an H-bomb isn't really useful for commercial electricity production; there has to be some way to control the fusion reaction. One is using magnetic confinement, in the tokamak -- a transliterated Russion word, created from the (Russian words for) "toroidal chamber in magnetic coils". Frankly, the physics of them is a bit beyond me. My sense is that a magnetic field is used to rapidly heat (and maintain the heat) of the plasma in a fusion reactor. Alternatives include the Z-pinch system (again, the physics surpasses me) and laser inertial systems. Confinement has to maintain the plasma in the fusion reactor in a dense and hot enough state that it will undergo fusion and produce energy, and to keep the plasma in this state such that it can continue to undergo fusion.

The third is the choice of materials. As said, fusion reactions can induce radioactivity in the materials used in the reactor structure. Furthermore, the temperatures in a fusion reactor are extremely high. Very few materials would be able to withstand the thermal and mechanical pressures inherent in a commercial fusion power plant.

Unfortunately, at this point in research, it's by no means clear that commercial electricity generation from fusion reactors is even possible, at least in a way that would be economically viable. The promise is of fairly high power-generation without interruption, and without significant environmental effects. But whether this promise can be fulfilled is extremely unclear.

Sources:

http://en.wikipedia.org/wiki/Fusion_power
http://en.wikipedia.org/wiki/Tokamak
http://en.wikipedia.org/wiki/Induced_radioactivity
http://en.wikipedia.org/wiki/Z-pinch

Thursday, August 23, 2007

The connection between means and ends and its consequences for the teleological model of reasons-explanations of action.

A third in a series of unknown length. The previous post is here. In the current post, I intend to complete the sketch of the teleological model of reasons-explanations of action that I want to defend. (Of course, I'm going to do so in an incredibly sketchy, promissory note kinda way.) To do so, I have to, as said previously, answer two questions:
  1. What is the connection between means and ends?
  2. What sort of account of value underlies this picture?
Answering these two questions will, I think, fully characterize the sense in which teleological reasons-explanations explain action by showing that the action fit into some efficacious value-increasing pattern.

One move I want to resist is the claim that the connection between means and ends is purely psychological. I want to resist this for a couple of reasons. First, I don't think we gain anything useful by creating a psychological state -- "purposes" -- to play the role of ends. Everything that a purposes-model can capture, I claim, can be captured just as well by a goals-model, where goals are conceived of as states of affairs that agents (attempt to) bring about. Second, I think it will just resurrect the "trying" problem, where I am somehow absolved of practical responsibility if I just try to take appropriate means for my ends. If the connection between means and ends is just in my head, then it seems I cannot be blamed as long as I make my utmost effort to get the connection right. But that strikes me as extremely odd; surely getting the connection right is what matters, not making a really good effort to do so.

I think there's something to this idea that the connection between means and ends is one of propriety or appropriateness. (I like "propriety", so I'm going to use it. Nice-lookin' word, and kinda fun to say.) That is, we can say a given means -- say, φ-ing -- is connected to a given end -- say, ψ -- if the means is appropriate for the end. To make it more technical-sounding, φ-ing is connected to ψ if (and only if?) φ-ing is appropriate for ψ. So, taking my umbrella is connected to not getting wet if taking my umbrella is appropriate for not getting wet. If taking my umbrella is not appropriate for getting wet, then there's no connection between taking it and not getting wet; taking my umbrella must be appropriate for some other goal (maybe it makes me feel comfortable to carry an umbrella around) or taking my umbrella is not something I do for reasons (maybe it's just reflex; as I go out the door, I grab my umbrella).

So, what does propriety amount to? I'd have to be convinced, strongly, that this is a matter of efficacious causal connection between means and ends -- that is, something like a means is appropriate for an end if it causes the end to obtain. For one, this fails to distinguish between what the means is for -- the end or goal -- and what the means just happens to produce -- that is, good ol' epiphenomena. For two, it would also force us into a probabilistic model of causation -- in order to capture the idea that several different means could be more or less appropriate for a given end -- I'm sympathetic to the idea that it's counterfactual. That is, a means is appropriate for an end if the end would not obtain without the means. The obvious problem, though, is that there could be a multitude of appropriate means for an end, so we'd have to set up a fairly complicated counterfactual. I'm not sure that propriety is as complex as all that.

Ultimately, the strategy I think I want to pursue is more radical than either of these alternatives: I want to, basically, (1) collapses (or maybe staggers broadly) into (2). I take the task of finding the connection between means and ends to just be the task of figuring out a workable sketch of value. This is because of the obviously normative connotations of something being "appropriate" for something else. (I suppose my choice of the word "propriety" was not entirely accidental. Heavens.) To be appropriate is to conform to some set of rules, or to exhibit some sort of relevant value. My behaviour is inappropriate if it is, say, rude, or if I'm breaking a law; my behaviour is appropriate if it is polite or in compliance with the law. So, under this view, φ-ing is connected to ψ if φ-ing is appropriate for ψ and φ-ing is appropriate for ψ if either φ-ing for ψ conforms with some relevant rule or φ-ing for ψ is valuable, for some relevant value. The rules and values, since I'm trying to pitch this at full generality, are going to have to be rules and values of practical rationality.

This, I think, will rather neatly solve my problem with (2), as well. It's not quite as nasty a problem as I might have thought; I'm dealing with a pretty broad set of rules and values when it's a matter of practical rationality. (I was worried that the teleological model I want to defend would have to rest on some highly contentious claims about moral value, say, which would have been a whole dissertation in its own right.) So, moving on to (2): the values and rules of practical rationality aren't really all that different from the values and rules of theoretical rationality. That is, when we're trying to figure out what to believe (or, if you like, what propositions are true) we're reasoning in the same way as when we're trying to figure out what to do. The difference is that theoretical rationality has a nice little goal built in -- figuring out what's true -- while practical rationality requires that we agents set the goal, and then reason our way back, in accordance with the rules and values governing practical reasoning, to the means.

What are the rules and values governing practical reasoning? I honestly don't quite know. But I do know that this is a problem which can, in the end, be solved. That I want to rely on them probably accounts for why I'm inclined towards Schueler's model, which also makes heavy use of practical reasoning, and away from Sehon's, which takes teleology to be an unanalyzed blob. Whatever the rules and values are, once they're uncovered, then the characterization of efficacious value-increasing patterns is complete: these patterns are just patterns of practical reasoning.

However, the solution, I think, will come in the third section of the dissertation, where I trace some consequences of adopting the teleological model for areas beyond action-explanation. For next week, I think it appropriate to spend some time showing that other models of reasons-explanation of action are wholly inadequate to satisfy the three basic criteria on a good reasons-explanation of action; that is:
  1. Account for the connection between reasons and action in the agent
  2. Give reasons that the agent genuinely finds worthy
  3. Fit the action within the pattern implied by (a) and (b)

Wednesday, August 22, 2007

Energy-generation: Future sources.

Note

In this post, I consider energy sources that have not yet been widely-implemented. Some, such as solar and tidal, are in the beginning stages of widespread implementation. Others, such as biofuel (for power generation, not vehicle fuel), are not. So, caveat: some of the claims about suitability here are a little on the speculative side.

Biofuel

At least according to Wikipedia, the most reasonable use for biofuel for power generation is biogas. This makes a certain amount of sense, given that natural gas is the best overall energy source of the fossil fuels, and that biogas is chemically similar (mostly methane and CO2). The structure of a biogas power plant is, thus, identical to that of a natural gas plant.

Biogas is produced by treating organic material, including biodegradable waste materials such as paper, food, and sewage, and crops grown specifically for their biodegradable content, in an anaerobic digester. The digester is a tank sealed to prevent the introduction of oxygen and contains bacteria which, ultimately, break down the organic matter into methane, CO2 and water. Since the tank is sealed, none of these products are released into the atmosphere, but can be harvested for human use. The bacteria themselves produce a waste product, called digestate, which can be used for soil conditioning .

However, all these products must be treated before they can be used or, in the case of the wastewater, allowed to re-enter the surrounding ecosystem. Biogas may require treatment before it can be used as a fuel, given that trace levels of certain chemicals (e.g., hydrogen sulphide) must be kept within strict limits in some jurisdictions. Furthermore, as with all biofuels, a key issue in adopting biogas is the feedstock required for the digester. Different materials have different gas yields; and some materials can't be broken down by the bacteria. Although sewage and manure can be broken down, much energy content of the organic material has already been lost to the animal that produced the waste. If the feedstock is contaminated with materials the bacteria cannot digest (such as glass or metal), the feedstock must be treated first in order to remove these contaminants.

Overall, the ecological impact of biogas is not huge. Burning it does produce greenhouse gases, but these are gases that have been only recently stored in organic material. If biogas is created from fuel crops, or vegetable food waste, then replanting these crops would, it seems, make biogas power at least close to carbon-neutral. Since biogas is chemically similar to natural gas, I would expect the energy production to be comparable.

Solar

There are a number of ways to create electricity from solar energy. The most commonly-known is via photovoltaic panels. These panels consist of a series of photovolatic or solar cells which chemically convert sunlight into electricity. Perhaps the most obvious application of this technology for energy generation is not in the form of large power plants, but building (and even vehicle or road) installations. They can thus be added to other forms of energy production (e.g., on the roofs of power plants). Something I didn't know, until today, is that there are large-scale photovoltaic power plants in Europe, and otehrs planned in Australia. These consist, as one would expect, of large banks of solar panels, some of which are designed to follow the sun as it moves across the sky.

Heat from the sun can also be used to generate electricity. The process should be familiar at this point: water is heated by the heat from the sun, and used to drive a thermal power plant, which converts the hot water/steam's energy into electrical energy. There are several different designs for capturing the heat, ranging from large trough systems to flat-plate systems to parabolic dishes. One that I found particularly interesting is the "power tower", which uses an array of mirrors to focus the sun's rays on a central tower, which contains a substance capable of storing the heat energy for later use in boiling water for steam turbines. Since the material in the towers is capable of storing heat energy, it is at least in principle possible to use them to generate some electricity during the night. (Although they would, obviously, be unable to handle any sudden increases in demand.) Thermal systems have, however, fairly low conversion efficiencies: according to Wikipedia, this can range from 20% to 40%, at best.

There doesn't seem to be any necessary problem with the cost of these technologies; as demand increases, price will drop, thus reducing the capital cost (and, it should be noted, also associated costs, such as panel installation). The production of the panels, mirrors, etc. is, environmentally, a possible problem: the resources consumed are limited, and the production processes do produce waste. However, solar is in this respect clearly superior to fossil fuel plants; and, indeed, anything humans build is going to consume something. The biggest issue I see is one that parallels a problem with wind: you need some other sort of technology (either power storage or another sort of generating facility) to pick up the slack when the sun goes down, and the solar panels are incapable of generating. Power towers are a possible solution to this problem, but I remain dubious as to their ability to handle overnight shifts in demand.

Geothermal

Geothermal power is generated by boring holes into hard rock, then pumping water down one hole. The water would be heated, and emerge as steam from the second hole, which could be used to generate electricity by driving a good thermal power plant. Geothermal plants exist in a number of countries, but not on a particularly wide scale. Input costs are the obvious construction costs, plus the costs associated with developing and using the drills needed to penetrate the rock. Operating costs should be no different from any other power plant. Output costs would be minimal, if the geothermal energy is truly renewable. There is no fuel consumed and little waste, gaseous or otherwise, released; water/steam can be recycled and reused to drive the turbine(s), and waste gases are emitted in very low levels from plants which use underground hot water sources. It's not yet known whether locations used for geothermal energy would, eventually, cool down -- that is, if they can be depleted. This depletion is probably temporary, given the heat that exists in the Earth's mantle will replenish a given site, but it suggests this power source may not be as stable as we would like. There is also a (I would suspect small) chance that drilling for geothermal energy on a large scale would result in seismic instability.

Tidal

There are two types of tidal power installations. First are barrages, which convert potential energy of a higher pool of water into electrical energy, using turbines like those found in hydroelectric power plants. The higher pool or basin can be filled in one of two ways. Under ebb or outflow generation, water flows in until high tide, at which point a set of gates are closed until the sea level has fallen. The gates are then opened and the water flows through turbines. Under flood generation, the basin fills through the turbines, generating electricity at flood tide. Barrage systems have all the attendant problems of hydroelectric dams: environmental impacts and significant capital costs being the most prominent. However, like hydroelectric dams, barrage systems do not consume fuel, do not produce waste, and have very low operating costs.

Second are tidal stream generators, which are, in essence, underwater versions of a wind turbine. (See here for such a system about to open off the cost of Northern Ireland.) Evaluation of these is thus largely the same. Tides won't turn the turbines constantly, so the power generated must be stored somehow. However, tides are more predictable than the wind; and since the systems are underwater, the aesthetic considerations are nil. Furthermore, the tides are capable of producing more power, because they move water, which is hundreds of times denser than air. Like wind, tidal energy of this kind is essentially inexhaustible.

A related possible source of energy is wave power. Wave power can be harnessed to produce electricity in a variety of ways. For example, mechanical energy can be created by a line of buoys rising and falling with the waves, and this energy can be converted into electricity. Waves can also be directed into a reservoir and then used to drive hydroelectric generators. Most of these technologies appear to be in early development. In principle, though, they seem no better or worse than solar, wind, tidal or hydroelectric power generation: once the cost is expended to create the necessary infrastructure, the energy is renewable and emission-free.

Fuel Cell

Fuel cells produce electricity via a chemical reaction. A fuel and oxidant flow into an electrolyte, and the resulting chemical reaction produces electricity, which can be harvested for a variety of applications. There is a tremendously wide variety of fuel cell designs; I'm not even going to try to describe them in any depth. They use a variety of materials, operate at a range of temperatures, and have quite a range of energy efficiencies. Their application in power generation is, consequently, also quite varied. For example, according to Wikipedia, the Stuart Island Energy Intiative in Stuart Island, Washington uses solar panels to power an electrolyzer, which produces hydrogen (presumably from water). This hydrogen is then used to run a fuel cell which creates electricity. I mention them here only because, like small photovoltaic installations, fuel cells are a potential source of small-scale power generation. They could also be used to generate constant levels of electricity, serving as a back-up to power generating technologies (such as wind and solar) that are variable in their output.

Conclusion

Most of these technologies are not in widespread use, so evaluating them will get a little speculative. However, thus far, they all look fairly good. They consume fewer resources as input costs than conventional fossil fuel plants, or nuclear plants, for that matter. They also have low operating costs and output little more than electricity. Some are, however, limited. For example, solar technologies will only generate power during daylight hours. Wave farms and tidal power technologies are dependent on changes in water flow patterns; although these are predictable, they are nonetheless variable. Geothermal plants could temporarily exhaust underground thermal energy. However, biogas and fuel cell plants could, in principle, provide the needed backup to alleviate the loss of generation from one of these sources. No one is ideal, on its own, but a balanced and careful exploitation of a variety of energy generation sources may be, ultimately, the best solution.

The real question, though, is how long it would take to get these generating technologies working on a sufficient scale to meet both current and future energy needs. Except for fuel cells (depending on type), all the technologies discussed above require significant capital investment and time before they can generate significant amounts of electricity. And some, such as wave farms, are still largely in development.

Sources
http://en.wikipedia.org/wiki/Biofuel
http://en.wikipedia.org/wiki/Biogas
http://en.wikipedia.org/wiki/Biogas_powerplant
http://en.wikipedia.org/wiki/Digestate
http://en.wikipedia.org/wiki/Solar_power
http://en.wikipedia.org/wiki/Photovoltaics
http://en.wikipedia.org/wiki/Photovoltaic_power_stations
http://en.wikipedia.org/wiki/Solar_thermal_energy
http://en.wikipedia.org/wiki/Geothermal_power
http://en.wikipedia.org/wiki/Tidal_power
http://en.wikipedia.org/wiki/Wave_power
http://en.wikipedia.org/wiki/Wave_farm
http://en.wikipedia.org/wiki/Fuel_cell

Friday, August 17, 2007

Why the teleological model of reasons-explanations works, and what it looks like.

I'm continuing on from this post, and sketching the arguments of the second half of the first section of my dissertation. I'm going to be first, arguing that a teleological model of reasons-explanations of action fulfills the criteria on a good reasons-explanation; and, second, I'm going to try to unpack what I think this teleological model looks like.

I'm working with three criteria; a successful reasons-explanation of action must:
  1. Account for the connection between reasons and action in the agent
  2. Give reasons that the agent genuinely finds worthy
  3. Fit the action within the pattern implied by (a) and (b).
How does a teleological model pull off these three? Generally speaking, to call something "teleological" is to say it makes important use of some telos, which is variously translated as "goal" or "purpose" or "end". When trying to characterize a teleological model generally, I like to use "end" as I find it ambiguous between "purpose", which seems psychological, and "goal", which seems not. So, a teleological model of reasons-explanations of action (hereafter "T-model", 'cause typing "teleological" is getting old) is one that explains action by pointing to reasons as ends. For example, if I take my umbrella when I leave the house, a plausible way to explain this by reasons is to point to "not getting wet" as an end that I had. Whether or not my action was rational depends on whether or not I achieved this end. If my umbrella happened to have a hole in it, then taking it was a terrible way to avoid getting wet; that is, my action failed to exhibit (enough) means-end rationality. If getting wet is a valuable state of affairs, then my action failed to exhibit some more robust sort of rationality: rationality of ends, we might say. If there was no chance I might get wet, I'm inclined to say that I was even more irrational; not only is there something wrong with the way I try to interact with the world, but there's something wrong with the way the world is interacting with me. That is, I've flipped from being practically defective to epistemically defective.

It's important to note, I think, that there's room in this T-model for the claim that, sometimes, I don't actually act for any reasons at all, even though I very much try to. This would happen if something I thought was an end I could achieve turned out to be unachievable. It's important to draw this out as many traditional models of reasons-explanations of action don't have this feature. That is, much as Descartes et al elevated "seeming" into an unimpeachable theoretical activity, these models elevate "trying" into an unimpeachable practical activity. (I'm about 75% sure this is Robert Brandom's idea. Been a while since I read Brandom.) Retreating to "seeming" allows me to never make theoretical (e.g., epistemic) errors. My theoretical reasoning can never go wrong if I can always claim that I wasn't reasoning about what actually was the case, only what seemed to be. Similarly, my practical reasoning can never go wrong if I'm not reasoning about what I can actually achieve, but only what I can try to achieve. Many traditional models of reasons-explanations of action, in part because they are exclusively psychological, fall into this trap. I can always find some erroneous belief, say, that legitimates my course of action; I was just trying to do what the belief, mistakenly, told me was possible. I want to resist this move because, as said, it looks just like the seeming move: it's a fairly cheap way to resist the conclusion that sometimes we just go badly wrong. That is, sometimes we set ourselves goals that, although we tried as hard as we could, and reasoned as best we were able, just can't be reached. We thought we were acting for reasons, but we actually weren't. (Note that I've now basically kicked purposes to the curb; ends have to be understood as goals, or else the "trying" problem re-emerges.)

Back to the main line of argument. The T-model can, potentially, satisfy the first of the three criteria given above. The particular T-model chosen will affect whether or not the criterion is satisfied. But, in principle, there's nothing more or less mysterious about the connection between reasons and action being the connection between (approximately) ends and means than being the connection between causes and effects. Both sorts of connection need to be analyzed in more detail, but the analysis is, prima facie, possible.

The T-model can account for the second criterion rather more easily than most other models, the causal model in particular. To be an end for some agent just is for the agent to find the end valuable. Agents don't have ends that they find totally worthless; any such "end" is either really someone else's end, or not best characterized as an "end" at all. In the latter case, I'm thinking of cases of compulsion and the like, where an agent pursues "ends" that the agent doesn't want at all; in this case, I'm inclined to call the "end" no end at all, but instead something like a "result". A smoker who doesn't want to smoke any more, but does anyway, has smoking as a result of some of his actions. But it seems bizarre to me to call smoking his "end" when, ex hypothesi, he doesn't want to smoke any more!

The connection between means and ends, and the value the agent sees in the end, sets up a kind of pattern, as required by (c). We might call this a pattern of efficacious increasing of value. Really, though, this pattern is something of a pseudopattern; there's lots of detail that's obliterated if we try to capture the pattern as a unit. I think it's better to consider the efficacious increasing of value as a category of patterns, including patterns where one increases moral value (e.g., leading a virtuous life), material value (e.g., seeking wealth), practical value (e.g., survival), aesthetic value (e.g., the life of Gauguin), and so on. My examples are generally global, but I don't see any grounds for saying the efficacious value-increasing patterns have to be this way; they could be entirely local. This sort of thing would occur when someone does something "out of character": when Ned Flanders snaps and curses out pretty much everyone in Springfield, for example. That's a pattern of action, but one that's generally foreign to (at least the adult) Ned.

Characterizing the T-model more precisely then requires, I think, two things:
  1. An account of the connection between means and ends
  2. An account of value, at least in sketch
These two will in turn characterize the sort of pattern that exists between the connection and the value in any given case of action, and thus fully characterize the T-model.

(2) is a nasty problem, and I don't know, at this point, how to approach it. (1) is less nasty, although I don't have any firm opinions on it. So, I'll close with some sketches of two views on this subject, from GF Schueler and Scott Sehon. I'm more inclined towards Schueler's position, but not very strongly. My biggest problem with Sehon, I think, is that he doesn't really do (1). There's some gestures, but no significant characterization. Schueler is better in this regard but is, I think, too enamored of the psycholgistic accounts of reasons-explanations to go where he should -- i.e., goals -- instead of where he does -- i.e., purposes. It should be fairly obvious, though, that much of what I say above is drawing off Schueler's theory.

Scott Sehon
[Précis of: Sehon, Scott R. 2005. Teleological Realism: Mind, Agency, and Explanation. Cambridge, MA: The MIT Press. (Amazon | MIT Press)]

Scott Sehon offers an explicitly teleological model of reasons-explanations of action. Says Sehon, "[t]eleological explanations explain the behavior by citing the state of affairs toward which the behavior was directed" (Sehon 2005, 135). We do this by assuming the agent is rational; for Sehon, teleologically explaining A's φing in order to ψ requires finding "a ψ such that φing is optimally appropriate for φing, given a viable theory of the agent's intentional states and circumstances." (ibid., 146).

The reliance on the rationality of agents is due to Sehon's claim that reasons-explanations of action are supposed to make the behaviour of agents make sense and thus, following Donald Davidson, show the agent to be maximally rational: "consistent, a believer of truths, and a lover of the good" (ibid., 139, quoting Davidson). Sehon identifies two axes or sorts of rationality: the appropriateness of behaviour for goals and the extent to which agents find their goals valuable (ibid.). So, in teleologically explaining action, we are showing that, given their circumstances, epistemic situation, and intentional states, agents' actions are both appropriate and serve some kind of practical value, such as desire-satisfaction or being pleasing (ibid., 139-40). States of affairs and other objects acquire value for Sehon by fitting into an overall pattern of life, i.e., a system of goals (ibid., 162-3). It should be noted that, as with Davidsonian radical interpretation, it is possible for Sehon's agents to be in error, if assuming the agents were correct in a given case would introduce other errors into the intentional system, or imply greater mystery in physical theory than is the case with other interpretations (ibid., 140).

Sehon is, oddly, against the idea that the reason for A's φing need be any sort of state. He agrees that it could be, but he claims that the natural way to read A φed in order to ψ is that A's reason for φing was to bring about ψ. "It is a mistake to look for a thing that is the agent's reason for φing, whether the thing be a state of affairs, fact, or psychological state." (ibid., 149). Furthermore, A's reason for φing may be whatever accounts for A's valuing of φing: A's desire for ψ or A's acceptance of ψing as a moral requirement are both equally good candidates, for Sehon (ibid., 149-51).

The ontological picture underneath this is a little complex. Reasons aren't real psychological states, nor real states of affairs. In fact, for Sehon, teleology itself is just irreducibly real (ibid., 172). We understand persons teleologically, he claims, and to try to do without teleology is to omit a large and important sort of knowledge and understanding (ibid., 224, 228). Teleology is thus not subject to elimination, for Sehon accepts a modest realist criterion of existence, such that whatever we can't do without in order to not leave inexplicable circumstances of mysteries must exist (ibid., 18-19). While teleology itself is, he acknowledges, a large mystery on this account, leaving it out seems to leave a greater gap (ibid., 171-2).

Once elimination is off the table, we must either reduce teleology, go to some sort of dualism, or adopt a nonreductive approach. The median is less simple than the latter, so it is immediately out of the running, except as a final default. Reduction, says Sehon, is a failure because of the impossibility of finding bridge laws that allow us to deduce the concepts of intentionality from the concepts of a (presumably more fundamental, on a physicalist picture) physical science (ibid., 29-30, 128). So, Sehon adopts a nonreductive account of teleology, founded on a supervenience relation between human mental facts and physical facts, such that the latter constitute the former (ibid., 114-6, 130). In short, then, human reasons for action -- purposes -- are constituted by physical facts and teleologically explain actions simply because we cannot understand persons as persons otherwise.

G. F. Schueler
[Précis of: Schueler, G. F. 2003. Reasons and Purposes: Human Rationality and the Teleological Explanation of Action. New York, NY: Clarendon Press. (Amazon | OUP)]

According to Schueler, reasons-explanations must refer to purposes, at least implicitly, or fail to explain (Schueler 2003, 1). Purposes, for Schueler, are assigned to objects or events, which requires that there be someone who assigned them (ibid., 4). In this way, purposes differ from functions, which, for a given object or event, are entailed either by its causal role or by its evolutionary history (ibid., 5). To say something has a purpose is to say it should or is supposed to do something, and not that it actually is doing this thing, or even that it could. Thus, nothing about what something is, or its history, or its activities, is relevant to determining its purpose (ibid., 6). Schueler does allow, though, that certain restrictions must apply: for one, "you can't assign a purpose to the nail on my wall." (ibid., 7, italics added).

The importance of purposes is that reasons-explanations succeed in explaining, when they do explain, partly by picking out the purposes. And this is not inconsistent, Schueler says, with the claim that actions are events and thus causally explicable (ibid., 8). Indeed, says Schueler, there's a sense of causal explanation such that to say x caused y is to say no more than y can be explained by x (ibid., 17). Regardless of how to understand causal explanations, of central importance for Schueler is that the purpose-based, teleological explanations of action cannot be further analyzed in other (non-teleological) terms (ibid., 20, 38, 56). Causal explanations are just one example of a failed to attempt to provide this analysis (ibid., 55).

When purposes explain an action, such as φing, says Schueler, the agent takes the importance of φing as a reason, while an observer would take the agent's pro-attitude towards φing as being his reason (ibid., 58-9). So, the agent's perspective is essentially normative in a way the observer's is not (ibid., 60). For Schueler, the agent's perspective is primary: "[i]t is only once we know how an agent understands the considerations she regards as relevant, which ones she holds more important, etc. … that we can figure out which, if any, pro attitudes to ascribe to her." (ibid., 67). Thus, we need not only understand the agent's purposes, but also what sort of character the agent has: for then we will understand why the agent takes certain features as important, and overlooks others (ibid., 69, 71). Character traits, for Schueler, are not an eliminable or reducible part of a reasons-explanation (ibid., 76).

A trait explains an agent's mental states, and allows an explanation to escape the chain of reasons. Any further explanation would not be a reasons-explanation, and would not need to be offered from the agent's perspective (ibid., 78-9). For Schueler, there is a difference between doing something generous and being generous: a complete set of extensionally equivalent mental states omits the role played by the whole set, which constitutes the trait (ibid., 77). To attribute a trait to an agent is just to say that "certain sorts of facts count for her as reasons (perhaps of a certain strength) to do certain sorts of things." (ibid., 81). These attributions are inherently evaluative, as they deploy what, Schueler says, Williams called "thick" moral concepts (ibid., 83).

Agents take things as valuable because of their characters; to take something, in this case, is to reason about it. An account of reasoning, for Schueler, must be an account of decisions between alternatives -- at least the alternatives of φing and not φing (ibid., 91). Practical reasoning is always about actions and has, as its conclusion, a claim about what one should do (ibid., 99). Theoretical reasoning follows the same model, where the action is the forming of a belief (ibid., 101). The difference between the two forms, says Schueler, is that beliefs have a test for success beyond justification, namely truth; there is no parallel for practical reasoning (ibid., 103). (Schueler just declares this, without considering some obvious examples, such as whether the action is sensible or appropriate.) For both theoretical and practical reasoning, reasons are reasons because they reflect "some value, a value derived from the purposive activity in which the agent is engaged." (ibid., 104). (On the face of it, this seems to be in tension with the idea that reasons derive their value from being held as valuable by agents with certain character traits. I suspect, though, that Schueler would want to say that the character traits make the agents sensitive to particular values associated with particular purposive activities. So, the values are in the activity, but the agent's character traits lead him to recognize the value and consider it important.) The epistemic values in theoretical reasoning derive from the activity -- belief-formation -- theoretical reasoning is used for (ibid., 104-5). So, practical reasoning generally, including theoretical reasoning, must show that "there is something to be said for doing whatever is being considered", some value that it serves (ibid., 105, italics removed). Correct practical reasoning requires appropriately weighing the facts being considered (ibid., 107). Facts or states of affairs are all that could give one reasons and thus are all that can be considered in practical reasoning (ibid.). Even factual errors or states that do not obtain can be used in practical reasoning (ibid., 114-5). Finally, practical reasoning must be evaluative, because it must yield a conclusion about what one ought to do. This is not possible if practical reasoning only takes into consideration descriptive claims of fact (ibid., 130).

In Schueler's view, explicit reasoning is the paradigm of acting for reasons. In practice, we may omit this explicit deliberation, but we cannot understand what we do without interpreting it as explicit deliberation (ibid., 136). Further, if one could have deliberated, and found better reasons and thus better courses of action, this is, in Schueler's view, grounds for criticism (ibid., 147). If the deliberative model is wrong, says Schueler, it must be impossible to act on deliberation. So, given that this is not impossible, the model must be correct. It understands agents as genuinely rational and thus is a wholly evaluative model (ibid., 149-50). By adopting the deliberative model, we see agents as rational in their selection of means and also of ends (ibid., 155). This two-pronged rationality is, for Schueler, the ultimate basis or ground for all other traits of character (ibid., 165).

Wednesday, August 15, 2007

Energy-generation: Current non-fossil fuels.

Hydro

Hydroelectric power is, generally, generated using the potential energy of dammed water and converting it, by driving a turbine and generator, into electrical energy. This can be artifically created by releasing water from a high reservoir to a lower one, a technique usually used to handle increased demand. (Tidal and other methods I'll cover later.)

Hydroelectric plants have absolutely no fuel cost. They also tend to last longer and have few regular on-site personnel, thus decreasing operating costs. Dams are also relatively low-cost, if the dams also serve other purposes that can generate revenue (e.g., reservoirs can be used for water sports, fish farming, irrigation, and flood control). However, there are strict limits on how many sites are appropriate for dam construction; and, since many sites are some distance from population centres, hydroelectric plants will require more transmission infrastructure than other technologies.

The most significant problem with building a hydroelectric plant is the potential for damage to ecosystems. Both upriver and downriver environments can be altered, affecting wildlife in a variety of ways. For example, turbine activity alters the speed and temperature of water flow, and oxygen levels can be changed from pre-dam levels. Furthermore, the failure of a dam can be disastrous. So, there is a long lead-time before a dam can be constructed, due to the need to carefully assess the potential a given area has for successful (and minimal impact) dam construction.

In terms of output costs, while dams themselves produce no emissions, the reservoirs can, if they contain plant material which then decomposes. This decomposition can release large quantities of methane, a greenhouse gas.

The generating capacity of a hydroelectric plant varies widely with the size of the dam. Suffice to say, though, given the limited potential development, hydro plants reliant on large dams are, at best, only a part of the long-term solution to power needs. Even if we factor in the possibility of small dams, there's still an upper limit to how many dams can be constructed -- and how much damage can be done to aquatic ecosystems -- before the cost of generating more power outweighs the benefit of the electricity gained.

Nuclear Power

Nuclear reactors work in almost the same way as fossil fuel plants. That is, heat is produced to boil water, which becomes steam, which drives a turbine, which turns a generator. The difference, of course, is that the fuel isn't burned; instead, a controlled chain reaction is used to generate the necessary heat. The fuel is a form of uranium, possibly enriched to have its uranium-235 (U-235) content increased above what is found in nature. As far as I can tell, all current commercial power-generating reactors use a moderating material of some kind to slow the neutrons emitted by U-235 as it decays. Slowing the neutrons increases the probability they will fission particles of U-235, and reduces the probability they will be captured by U-238.

There are a number of different reactor types in use. Most American reactors are cooled and moderated by high-pressure liquid water. Some use lower-pressure water, which can be allowed to boil (increasing efficiency, but also increasing stress on reactor components). The CANDU reactors (Canadian-designed) are cooled and moderated by high-pressure heavy water. RBMK reactors, a Soviet design, are water-cooled and use graphite as a moderator, but are considered unstable and highly dangerous. Gas-cooled reactors, originally developed in the UK, are graphite-moderated and cooled by CO2. Reactors cooled by liquid sodium operate by slightly different principles. They are entirely unmoderated and thus the probability of fission is lower. It's hard to see where the technology will go, so I'll try to speak of the costs and benefits of all reactors in general (allowing that this probably obliterates some distinctions). I think I can get away with this because the economic differences between reactor types -- for example, CANDU does not require enriched uranium -- can be oblitered by differences in the other direciton -- CANDU requires tonnes of nearly pure heavy water.

Generally speaking, the economic costs of nuclear plants are heavily-weighted towards construction. Maintenance and fuel are minimal by comparison. It's generally taken as gospel by anti-nuclear types that nuclear technology is too expensive; they like to point to the cost overruns associated with refurbishing Ontario plants, such as in Darlington. Whether or not nuclear is too expensive really depends on how much power we can expect nuclear plants to generate; however, it seems to me that the cost overruns in Ontario aren't entirely due to the technology itself. It's worth noting that CANDU reactors installed in other parts of the world managed to come in on-schedule and on-budget.

Construction cost estimates run from $1000 to $3000 per kilowatt-electric (i.e., per kilowatt of electric capacity). Fuel costs in 2007 are about $250/kg, and rising. Nuclear plants must also invest more in security than other generating technologies, given the possibility of sabotage or theft of nuclear material. And, nuclear plants are subject to stricter regulations, which also increases operating costs. Costs associated with mining uranium must also be factored into the input costs of nuclear reactors, as well as the fact that uranium supplies worldwide are limited, just as are fossil fuels. While it may be possible to use materials other than naturally-occurring U-235, there will still, inevitably, be a point beyond which there is no more fuel. (Pie-in-the-sky predictions about the longevity of nuclear fuel supplies sound, to me, like the promises made of fossil fuel supplies in the last-but-one century.)

As far as output costs, waste is a bit of a bugbear. Strictly, nuclear waste doesn't all have to be stored; it can be reprocessed for additional fuel, and for weapons material. While it's not perfect, it does suggest that fears of waste disposal may be exaggerated (to put it mildly). Furthermore, the amount of waste produced by nuclear plants is far less than the total amount of toxic industrial wastes from all industries; and burning coal releases even more radioactive waste. Radiation, generally, is a bugbear, as there is no evidence to support the claim that proximity to a nuclear plant increases one's chances of developing any kind of illness or injury. Nuclear plants also produce no airborne emissions: no greenhouse gases or any other pollutants. Reactors largely emit water vapour.

I'd be remiss if I didn't say something about Three Mile Island and Chernobyl, so: Three Mile Island is highly exaggerated, and Chernobyl is likely a one-time problem. Three Mile Island released very little radiation, much less than natural background radiation; there are also no confirmed injuries, fatalities or illnesses sustained as a result of the Three Mile Island accident. Chernobyl, by contrast, did kill thousands, and will probably go on to kill thousands more. However, the reactor designs were clearly flawed and have been significantly improved. (It'd be interesting to see if, and to what extent, there were accidents with early fossil fuel plants.)

In terms of cost per kWh, Wikipedia cites an MIT study which concluded the cost to be 6.7¢ per kWh; a US government 2006 study, assuming $1984 per kWe in construction (and related) costs, concluded nuclear power costs approximately 6¢ per kWh. Given that nuclear power is, ultimately, just a refined version of the technology used for fossil fuel plants, it strikes me that, as fossil fuels were a time-limited improvement on burning wood, nuclear power is not a long-term solution to power needs. This does not mean, though, that it'd be a good idea to not build any nuclear plants. After all, they're still, fairly obviously, better than fossil fuel plants. The question is whether they're better than the other contenders.

Wind Power

Generally, electricity is generated from wind power by converting the rotation of the blades of a wind turbine (kinetic energy) into electrical energy via a generator. Simple enough. Wind turbines will not, however, work in environments that routinely experience heavy wind gusts or temperatures of less than -20°C. Wind turbines can either be large-scale, and contained in large wind farms, or small, which can be attached to individual buildings to provide small amounts of electricity.

As far as input costs go, wind power requires no fuel. Installation costs in the US are around $1600/kW. As with hydro, most good sites for wind turbines are far from population centres, increasing the cost of transmission infrastructure; nonurban and offshore locations are probably best, in terms of reliable and usable wind, but will be most costly in terms of transmission needs.

The use of internal heaters, low-temperature lubricants, and the like can, in theory, allow turbines to operate in low-temperature conditions. However, this increases the operating costs of the turbine, as (for example) power is required, in some form, to operate the heaters.

In terms of output costs, wind power produces no emissions. Unlike hydro, it's not yet settled what effects, if any, large-scale wind farms have on surrounding ecosystems. It's probable that some species will be at risk, as with any other human activity, and we should try to minimize that cost. Certainly many people find them unsightly, but I'm confident many people also don't care one way or the other. The issue of noise pollution is exaggerated, as wind turbines produce sound levels comparable to a mild wind.

The cost of the electricity generated by wind turbines in 2006 was approximately 6&162; per kWh.

Albert Betz, according to Wikipedia, determined that a wind turbine can extract at most 59% of the energy that would otherwise flow through the turbine's cross section, as the air is slowed down by passing through the turbine. Due to the variable nature of windspeed, the amount of power generated by wind turbines will vary. The ratio of actual productivity in a year to the theoretical maximum capacity (the capacity factor) is about 30% for a well-sited wind turbine. This could be improved, in principle, by scattering wind farms in different climate regions, but it's probably impossible to have a perfectly stable energy supply based on wind power. Even energy storage solutions -- which, it must be noted, would increase the cost of wind power -- can only improve, but not resolve, the situation. Wind power is also plagued by the problem of the intermittency of the wind, and of the practical limit on the number of locations where wind farms can be placed before environmental impact becomes too great to be tolerated. As with hydro, it seems that wind can, at best, be a part of a long-term energy solution.

Sources:

http://en.wikipedia.org/wiki/Nuclear_power
http://en.wikipedia.org/wiki/Nuclear_reactor_technology
http://en.wikipedia.org/wiki/CANDU
http://en.wikipedia.org/wiki/Economics_of_new_nuclear_power_plants
http://en.wikipedia.org/wiki/Nuclear_reprocessing
http://en.wikipedia.org/wiki/Hydroelectric
http://en.wikipedia.org/wiki/Small_hydro
http://en.wikipedia.org/wiki/Wind_power

Sunday, August 12, 2007

A delay.

Urg. One week in and it's already falling apart!

Actually, the problem is I really can't read philosophy papers on a computer screen. I lose the thread of argument too easily. And, given that I can't even print anything out due to chronic underfunding (September really can't come soon enough), that pretty much puts philosophy out of the running for this week. Next week I should be able to put something together, though....

Thursday, August 09, 2007

Energy-generation: Fossil fuels.

(Ed. note: Since this is mostly general information stuff, I'm relying exclusively on Wikipedia. While they're not great on specialist topics, they're as good as any encyclopaedia on general ones. Also note, though, that this introduces an American bias in data discussed. I'm not aware of any reason to be concerned about that, though.)

Oil, coal, natural gas and other fossil fuels (including oil shale, which seems to me to combine the worst characteristics of coal and oil) are converted into electricity by approximately the same process. They're burned to produce heat; the heat is used to boil water and convert it to steam; the steam is channelled via a series of pipes to drive turbines; and the turbines are attached to generators, which convert the mechanical energy of the turbine's motion into electrical energy. There may also be a series of turbines attached to further generators, which are driven by waste gases and heat/steam.

All these plants, thus, share the same construction and maintenance costs. They also all use water in the boilers which, although it is recycled after being converted into steam, must be replenished due to minor steam leaks in the boiler system. It's also worth noting that all fossil fuel plants consume energy. For one, once the steam has recondensed, it has to be pumped back into the boiler for re-use. Figuring out a dollar amount for this class of input costs is, apparently, impossible. I've been Googling for the better part of an hour and have come up with zip in terms of costs of construction or maintenance costs for fossil fuel plants in either the US or Canada.

Fuel costs are variable. In terms of actual purchase price, according to the World Bank (.pdf), coal cost about $47.62/metric ton in 2005, $49.09/metric ton in 2006, and $57.32/metric ton in 2007. (Just to make my life easier, I'm assuming these and all other costs of fossil fuels fully internalize the economic costs associated with mining. Otherwise, I'd be doing this for months.) In terms of externalized costs, coal mining produces greenhouse gases and can impact on water-flow in mined regions. Coal can also introduce toxic chemicals into water, but mines are required by law to monitor and control this problem. By law, future coal mining sites must provide reclamation plans (i.e., plans for returning the land to a safe and usable state); but there is no such law for older mines, as far as I can tell. Once coal is mined, it must be transported to the plant and unloaded (apparently a more lengthy process than other fuels, given that it won't flow, unlike oil or gas). It must also be (mechanically) pulverized to a fine powder before it can be successfully burned.

Crude oil, according to the same World Bank .pdf, cost $53.39/barrel in 2005, $64.29/barrel in 2006, and $63.38/barrel in 2007. Petroleum extraction appears to be less environmentally costly than coal extraction. (Although, interestingly, Wikipedia notes there are several methods currently in use -- and others being developed -- for transforming coal into an oil substitute.) Costs associated with using fuel oil rather than coal are for me hard to determine, given that natural gas appears to be the preferred alternative to coal, as far as fossil fuels go. So, with that in mind, turning to natural gas....

According to that World Bank .pdf, natural gas cost $8.92/million BTUs in 2005, $6.72/million BTUs in 2006, and $7.20/million BTUs in 2007. (One million BTUs is equivalent to 1 gigajoule and, according to this, thus 278 kW-h.) Natural gas must be processed before it can be burned in a fossil fuel plant. "Raw" natural gas is a combination of various hydrocarbon gases, some of which (e.g., ethane, propane, butane) can be sold commercially once extracted. Sulfur can also be extracted for use. Others (e.g., carbon dioxide) are considered waste and incinerated once extracted. Transportation of natural gas is also problematic, as it must be compressed or liquefied in order to be transported on carriers, adding to the cost. Alternately, it can be piped from its source, but this can be impractical over long distances. Natural gas is generally found in naturally-occurring gas fields, but can be produced by treating coal and from biological material. The latter is still largely in development.

In terms of output, all these plants are a significant source of air pollution. Coal plants are the worst offenders here, but no fossil fuel -- not even natural gas -- is exempt. Burning coal produces several toxic gases which have to be removed through, for example, limestone wet slurry in exhaust stacks. Burning coal also produces ash which, if removed with filters, can (sometimes) be recycled for other purposes (such as manufacturing concrete). It is also possible to combine the emitted gases with water, and use the result to drive a gas turbine. Fossil fuels can also contain trace amounts of radioactive and toxic metals, and this is not an insignificant problem, given the volumes consumed by fossil fuel plants. All fossil fuel plants emit carbon dioxide and there is no known way to deal with it. Of course, CO2 is known to contribute to global warming. So-called "clean coal" plants would have to eliminate all these emissions and, as yet, the process is theoretical. Clean coal technologies may also be cost-prohibitive. Natural gas produces less of these pollutants, in part because it has been purified through processing, in part because it contains less carbon and thus releases less CO2 when burned. It is still, however, polluting.

In terms of energy production, fossil fuel plants vary depending on technologies used. Efficiency for coal can be as low as 35% (i.e., 65% of energy produced lost to the environment in the form of heat) or as high as 50% (if steam is superheated). (It is, in principle, possible to convert coal into a gaseous form that could be used in a fuel cell, which would drive efficiency, possibly, as high as 85%. These cells are currently still in development, and thus I'll cover them in a later installment.) Coal contains about 6.67 kW-h of energy per kilogram. Using the efficiency numbers above, this works out to about 2.3 to 3.3 kW-h per kg of coal produced by coal plants. Using the 2007 cost above, given that a metric ton is equivalent to 1,000 kg, 1 kg of coal costs $0.04762, or about 5¢. So, 1 kW-h of electricity produced by coal costs between 2¢ and 1.5¢ (at most and least inefficient, respectively). (I know that's just counting the fuel costs, but I can't find numbers for the other costs. So, it's a conservative estimated cost.) Unfortunately, I can't calculate the energy production for natural gas, as the data don't appear to be easily available. However, given the 2007 cost of natural gas above, and the conversion of 278 kW-h equalling 1 gigajoule, it follows that natural gas costs about 3¢ per kW-h.

In terms of jobs sustained, a little over 100,000 miners work in coal mines in the US. Coal mining is the second-most dangerous occupation in the US, in terms of worker injuries and fatalities. Comparable figures are, again, not readily available for natural gas.

So, surveying the fossil fuels, it seems they have two main advantages. They're (currently) not too expensive to extract, and the plant technology is not terribly complicated. Thus, I would expect fossil fuel plants to be the cheapest power plants, in terms of construction, maintenance and operating costs. (Of course, the latter is a bit of a guess, as I can't find the data.) They have two disadvantages, though. They produce a lot of pollutants, primarily into the air, and they're finite resources. Overall, it seems that natural gas is the best of the three possibilities, given that it is less polluting, not obviously less productive, and only marginally more expensive. (Without efficiency numbers, it's hard to estimate the costs.) It's a slight advantage, though, from my perspective. So, I'll take it that none of the fossil fuels is clearly superior to the others.

Next week: hydroelectric, nuclear fission, and wind power.

Sources:
http://en.wikipedia.org/wiki/Fossil_fuel_power_plant
http://en.wikipedia.org/wiki/Coal
http://en.wikipedia.org/wiki/Coal
http://en.wikipedia.org/wiki/Clean_coal
http://en.wikipedia.org/wiki/Petroleum
http://en.wikipedia.org/wiki/Extraction_of_petroleum
http://en.wikipedia.org/wiki/Oil_shale
http://en.wikipedia.org/wiki/Non-conventional_oil
http://en.wikipedia.org/wiki/Natural_gas
http://en.wikipedia.org/wiki/Natural_gas_processing

Wednesday, August 08, 2007

24-hour delay.

I was on vacation on Monday, so my week is slightly time-shifted. Next installment of the energy generation series will be up tomorrow.

Thursday, August 02, 2007

What does a successful reasons-explanation of action look like?

The project I've set myself is figuring out reasons-explanations of action. I'm a big fan of the idea of having particular questions for any given project, on the grounds that, without a question, you can just keep investigating and researching with no particular end in sight. Having a question sets an end: once the question is answered, the project's done. So, the questions I'm trying to answer are two. First, what is the form of a reasons-explanation of action? Is it causal? Lawlike? Teleological? Something else? And, second, what consequences does this have for (a) the nature of reasons, (b) the nature of agency, and (c) metaethics.

Particularly, under (a), I'm interested in the question of whether reasons for action are psychological (e.g., I went to the store because I wanted some milk and believed they had it) or not (e.g., I went to the store because it had milk). I'm also interested in the question of whether reasons are simple (i.e., when I do x, I do so for one reason) or complex (i.e., when I do x, I do so for a constellation of reasons), and whether they are plural (i.e., any given reason can favour multiple actions, and any action can be favoured by multiple reasons) or not (i.e., any given reason can favour only one action or any action can only be favoured by one reason).

Under (b), I'm interested in what agents -- basically, people, but it could include non-humans, and even highly-intelligent robots or computer programs -- have to be like in order to be able to act on the basis of reasons and use reasons in reasoning about potential courses of action.

Under (c), I want to talk about whether there's a viable distinction between the "merely" practical and the moral. I think there is, but it's contentious, so I need to argue that my view of reasons-explanations gets the distinction off the ground. I also want to tackle the debate between motivational internalists and externalists, i.e., the issue of whether grasping or understanding a reason automatically motivates one to act, or whether motivation is a seperate "add-on" to grasping reasons. (I'm leaning towards the latter at the moment, but I have no firm convictions.) Maybe also some stuff about moral ontology and epistemology, which would seem to follow from the answeres to (a) and (b), combined with the first issue under (c).

The first half of the first section of the dissertation will argue for three criteria on a successful/satisfying reasons-explanation of action. The second half of that section will argue that the teleological model of reasons-explanations satisfies them, more fully characterize the teleological model I'll be working with, and defend the teleological model against objections. The second section will argue that no other model can do satisfy these criteria, either in particular incarnations, or in general. I'll consider three types of non-teleological models: causal models; law-based and anomological generalization-based models; and "the rest". The third section will trace out the consequences of the teleological model, as mentioned under the second question above. What I want to tackle here is outlining the arguments of the first half of the first section.

My sense is that we offer reasons-explanations of actions because we're looking to understand the actions. It's not just for fun or because it serves some sort of social function or what have you. And what we're trying to understand is why that agent performed that action. In other words, we're trying to understand four things:
  1. How did the reasons lead that agent to that action?
  2. What did the agent see (in the reasons) that made the action worth doing?
  3. What was the action that the agent did, exactly?
  4. What is the agent like such that he does such actions for such reasons?
(1) has often been interpreted causally. It need not be. To take it as meaning something causal requires assuming that "leading", in this sense, can only be understood in a mechanical, proximal causation sorta way. But, as Michael Smith points out (and I'm sure others do as well), you don't have to be committed to a causal understanding just because you think you can account for how reasons lead agents to actions. G. F. Schueler makes a similar point, but in a different way: he argues that there's an understanding of "cause" which just means "whatever follows the word 'because'". In other words, we can reinterpret causal explanations such that they are co-extensive with successful explanations.

What matters for me is that there are several other viable ways of understanding the way in which reasons "lead" to action, and it's by no means obvious (tradition notwithstanding) that it has to be causal. Perhaps reasons lead agents to action because there are true generalizations such that certain reasons had by agents always lead to certain actions. These generalizations could be laws of nature (not a terribly plausible line, but a possible one), or just useful "rules of thumb" for us humans. We could also say that reasons lead agents to action because when we look at the action, we can construct a history that places the action as a response to something in the agent's past. Rüdiger Bittner has this view. I'm not sure how much sense it makes, because I'm not sure what sense can be made of the idea of a "response" without falling into good ol' mechanistic, proximal causation, but I'm willing to allow it may be interestingly different. Finally, we could say that reasons lead agents to action because reasons show agents (or simply are) goals they could accomplish. This would require making sense of what pursuing a goal is, a task which I don't think is impossible.

(2) should not be contentious, if it's interpreted right. (J. David Velleman notwithstanding.) Any agent who does something for reasons which show it to be completely worthless is not really acting for those reasons. He's acting either for some other point (e.g., because he thinks doing something worthless is, in this situation, actually worthy) or he's being compelled somehow. It's important, as said, to read this right. It's not that something has to be worthy, all things considered, come what may, after examing all possible courses of action and carefully weighing the value found in each. All that's being claimed is that the action has to somewhat worthy: that is, the action has minimal practical value. Otherwise, we really haven't found a reason for that agent to do that action.

(3) may sound odd, but part of what picking out reasons does is also pick out an action. Certain reasons are inappropriate for certain actions. That is, as Donald Davidson said, reasons-explanations only explain relative to particular ways of explaining the action. "To turn on the lights" is not a reason for "startling the burglar" nor for "adding $.30 to my electricity bill this month", although it may be a reason for "flicking the lightswitch". So, (3) says nothing more than reasons and actions come together. (Although, as I've said already, part of what I want to do is figure out how tightly reasons and actions are bound together. My current thought is that the connection is pretty tenuous.)

(4) comes together with (2). If we show that the action was worth doing in the agent's eyes, then what we're doing is showing that the agent was a being such that the reason is worthy for him. That is, giving a reason that the agent found valuable requires that the agent be such that he accepts such value and is capable of recognizing it in this situation, and acting upon this recognition. If the agent doesn't care about animals, or didn't see one, or was unable to operate the car properly, then the reason for his action of turning the car sharply to the right when noticing a squirrel in the road can't be "because he doesn't want to hurt the squirrel". We have to find something he actually values. Perhaps his companion is squeamish and he doesn't want to offend her. Or perhaps he just bought new tires and doesn't want to get squirrel guts on them. (A good theory of reasons-explanations has to accept the the minimal practical value may not be equivalent to the all-things-considered practical or moral value.)

So, I can come up with three criteria that any reasons-explanation of action must satisfy:
  1. It must account for the connection between reasons and action in the agent [from (1) above]
  2. It must give reasons that the agent genuinely finds worthy [from (2) and (4)]
  3. It must fit the action within the pattern implied by (a) and (b).
Let me say more about these.

(a), as said, doesn't have to be read causally. What's important for (a) is showing that the reasons, the action and the agent collectively form some sort of pattern. If they can't be fit together (and I know "fit together" has to be given some more specific formulation), in some way, then there's just no explanation to be had. Either the action is characterized/described incorrectly, or the reasons are, or the agent is (or some combination). Or, of course, this is just not a case of acting for reasons. Not everything agents do counts as acting for reasons. (Whether or not action has to be identified with acting for reasons is a problem for another time, methinks.)

(b) claims that it's not enough to give reasons that the agent finds worthy, but really aren't. That is, subjective value doesn't cut it. This may seem odd, but the reason is simple: subjective value, at least in this context, is explanatorily imparsimonious. This is because everything that subjective value is introduced to do can be covered by objective value, but not everything that objective value does can be covered by subjective.

There are two distinct ways in which anything may be valuable, which may be called "subjective" and "objective". If we're talking about subjective value in this context, then the claim is that an agent has a reason to φ if the agent saw something about φ-ing that, in the agent’s eyes, made φ-ing worth doing. It may be that the feature(s) the agent focused on had no actual value, or even had disvalue. By contrast, if we're talking about objective value, then an agent has a reason to φ if the agent saw something about φ-ing that actually made φ-ing worthwhile.

Subjective and objective value come apart in two types of case, when they disagree on whether or not value is present, i.e., (i) when there is subjective value but no objective value, and (ii) when there is objective value but no subjective value. The supporter of subjective value can accommodate (i) easily, as it is just the case he would appeal to in order to justify asserting the existence of subjective value. After all, if the agent believes that φ-ing is worth doing, but is wrong, then surely his belief is enough to make φ-ing worth doing for him and give him some reason to do it.

However, this supporter will have difficulties if he concedes that in (ii) there is value present -– just not value for some agent. If objective value is allowed in (ii), then what should be said about its absence in (i)? Is it the case that objective value is a "fallback" from subjective, and thus only appears when there is no subjective value? This would be a strange and awkward view. Alternately, accepting objective value is as viable as subjective, is (i) a case with both the lack of (objective) value and the presence of (subjective) value? Surely this is contradictory. Perhaps this supporter could just deny there is any reason to φ in (ii), but this sounds extremely strange. A valuable feature in φ-ing, even one not appreciated, surely does in some sense give one reason to φ. Denying there is any reason here just looks dogmatic. The only remaining option seems to be to deny objective value altogether. But I think this sort of conclusion should fall out of an understanding of action, not be used to shore it up.

Subjective value may, for all its problems, still be superior to objective value. Suppose we completely reject subjective value. How would we thus be forced to interpret (i) and (ii)? In (i), a supporter of objective value can simply assert, as one sensibly might, that it is a case of error on the part of the agent. The agent believed, incorrectly, that φ-ing was worth doing. Consequently, if the agent did in fact φ, it would follow that the agent had no reason to do so, but only believed he did. Cases of believing, erroneously, we have reason for what we do seem fairly common, so this perspective on (i) is fairly comfortable. The supporter of objective value's view of (ii) is just as simple and comfortable: he would claim that, in (ii), the agent has just failed to appreciate a valuable feature. It is another kind of error, the mirror of the previous: instead of taking something to be valuable that actually was not, the agent has fail to consider something valuable that actually was. Again, I think that cases of overlooking important features of situations are fairly common.

Overall, then, trying to bring subjective and objective value together leads to a series of untenable contortions, and subjective value all on its own can't just be presumed. (Yeah, I know that latter one is weak. I'm still thinking about the consequences of rejecting subjective value at this point. I suspect it requires extremely weird interpretations of (i) and (ii), but I'm not sure how to phrase it.) Given that objective value has no need to go through these contortions, I conclude that it should be accepted.

(c) is sort of inevitable. Once we know what the reasons are and what the agent is like, there are going to be limits on what the action can be like. On its own, a theory of reasons-explanations probably won't put too stringent limits on what actions are -- events, processes, states of affairs, what have you. But, at least how we describe or characterize the action is going to be limited.

Wednesday, August 01, 2007

Energy-generation: Costs and benefits.

Let me start by motivating the project a bit. Electricity demand isn't going down any time soon. Sure, there may be sensible ways to increase efficiency. After all, if current smart metering initiatives become widespread (for example), there'll be sound financial reasons to stop using so much friggin' power, or at least use it during off-peak times. Overall, long-term, wide-scale conservation is a pipe-dream, though. So, we need to be able to generate more power. However, many current technologies are, not to put too fine a point on it, filthy. (Coal and gas plants, I'm looking at you.) Others are (perhaps with justification, perhaps without) feared or of limited applicability. (Fission and hydro, to name two.) So, what do we do? The answer, of course, is that we need to build more generators, in a way that maximizes gains, while minimizing all the relevant costs.

The costs I see are three, and they're related to different stages in the power-generating process: namely, the input into the generator; the process of running the generator; and the output of the generator (excluding power, which is not a cost). The first I'm thus going to call "input costs". This includes things like fuel. Fuel costs, of course, don't apply to all technologies. For example, we don't have to pay anything for the sun, so solar technology has a zero fuel cost. Ditto for wind. However, coal, gas, oil, and nuclear plants (to name a few) all require extraction and refinement of some kind of fuel. Furthermore, extracting all these fuels itself exacts a cost, in terms of resources consumed, risks to miners, and so on. And there are also the construction costs: some plants are just really expensive to build. I suspect strongly that the cost of the average nuclear reactor is many times more than the cost of the average windmill, or even windfarm.

The second I'll call "operating costs". Every power plant or other power-generating structure in the real world is made out of real materials, which degrade with use and have to be maintained. And people have to be maintained to monitor and repair these structures. Into this category, then, go all the costs that are created simply by running the generating structure, whatever it may be. I'm honestly not sure what might go in here, generally speaking, so I imagine my ongoing investigations will be quite enlightening in this regard.

The third I'll call "output costs". The obvious candidate for this category is emissions. Oil, gas and coal plants all dump greenhouse gases of various kinds into the atmosphere, as well as other toxins. Nuclear plants create radioactive waste which somehow has to be contained and safely disposed. Windmills are alleged to create an "audio pollution" in terms of the sound produced by their rotation.

The benefits I see are two. The first is obvious; it's the direct benefit of building a power plant (or windfarm or whatever). That is, it's electricity. Every generating technology currently in existence produces different amounts of power at different rates. This is something that, clearly, has to be taken into account when we're evaluating what the best form of generating technology is. If good ol' petrochemical technology just creates a ton of energy, it may be that the benefits outweigh the costs. (That might suggest a flaw in my cost-benefit style of analysis; since I doubt that'll be the case, though, I think the methodology is going to work just fine.)

The second is perhaps not so obvious, but it deserves to be considered, and that's the indirect benefits of building a power plant or similar generating structure. The most prominent benefit included here would be job creation. Closing all the coal plants in the world would throw thousands of mining companies out of business, and tens of thousands of people out of work. It's just naive to ignore the fact that certain technologies will have positive labour impact that deserves to be counted in their favour.

With these five principles in hand, in my next post, I'll turn to the petrochemical technologies currently in existence: oil, gas and coal (including so-called "clean coal"). I'll look at how each works, then discuss the costs and benefits according to the format outlined above. And we'll ultimately see which technology would best serve our energy needs....

Still not dead.

I've had some time to think about the direction for this blog. Snarking about MSM and blog articles if fun, but ultimately not satisfying. At least not to me. The most satisfying thing I've blogged here recently was the long healthcare post. I'm thinking I should be doing more like that. I'd also like to inject some more philosophy into the blog. As astute (and non-feed-using) readers will note, my profile on the right has changed to reflect the fact that I've gotten a contract teaching position at Trent in Oshawa this coming academic year. Hence, I feel the need to hone my philosophical chops as much as I can.

The plan, thus, is this. One policy/politics related post at the beginning of each week (Monday to Wednesday). One philosophy related post at the end (Thursday to Sunday). Both will be fairly lengthy and in-depth. I may, occasionally, resort to snarking if I feel it's well-deserved.

With regard to the policy/politics business, I'm currently planning a six-part series (starting today, ending the week of September 5th) on electricity generation. I'll start today with the principles I consider relevant to deciding between various forms of electricity generation; then move (in four parts) through data relevant to these principles, grouped into several categories (petrochemical, current non-petrochemical, future development possibilities, and the ideal sources); and conclude with an evaluation of all sources. My suspicion is that fission will win out, but if the data don't back it up, then I'll conclude differently. Beyond that, I'm thinking of tackling the issue of open access to research. I don't yet have plan for addressing it, though.

With regard to philosophy, I have a number of saved papers I find interesting and worthy of comment. I'm also still working on my friggin' dissertation proposal draft, so I'll probably start with an early run-through of an argument I'm going to open the diss. with. Since it's a first-run, it'll probably be full of holes, but I'm hoping that running through it will at least show me where it's weak and where it works pretty well.

I'm hoping this won't chase away my (handful of) readers. But, even if it does, I think it's a plan I can stick to even when the academic year picks up again, so I'm hoping to see it through long-term.