Concretizing the abstract is an interesting blog post in that it makes a relatively cogent argument for non-reductionism. While I don't agree with it, I found it useful in that it helped me better understand how intelligent non-reductionists think. It also helped clarify to me an old distinction, that of philosophers versus engineers.
We abstract when we consider some particular aspect of a concrete thing while bracketing off or ignoring the other aspects of the thing. For example, when you consider a dinner bell or the side of a pyramid exclusively as instances of triangularity, you ignore their color, size, function, and metal or stone composition. Or to borrow an example from a recent post, when aircraft engineers determine how many passengers can be carried on a certain plane, they might focus exclusively on their average weight and ignore not only the passengers’ sex, ethnicity, hair color, dinner service preferences, etc., but even the actual weight of any particular passenger. [...]Abstractions can be very useful, and are of themselves perfectly innocent when we keep in mind that we are abstracting. The trouble comes when we start to think of abstractions as if they were concrete realities themselves -- thereby “reifying” them -- and especially when we think of the abstractions as somehow more real than the concrete realities from which they have been abstracted. [...]I do not mean to deny that abstractions of the sort in question may have their uses. On the contrary, the mathematical conception of matter is extremely useful, as the astounding technologies that surround us in modern life make obvious. But contrary to what some proponents of scientism suppose, it simply doesn’t follow for a moment that that conception gives us an exhaustive conception of the material world, for reasons I have stated many times (e.g. here). [...]Then there is social science. When we abstract from concrete human beings their purely economic motivations, ignoring everything else and then reifying this abstraction, the result is homo economicus, a strange creature who, unlike real people, is driven by nothing but the desire to maximize utility. Nietzschean analyses of human motivation in terms of the will to power are less susceptible of mathematical modeling (and thus less “scientific”), but are variations on the same sort of error. Evolutionary psychology often combines abstractions of the natural scientific and social scientific sort. Like the neuroscientist, the evolutionary psychologist often treats parts of human beings as if they were substances independent of the whole from which they have been abstracted (”selfish genes,” “memes”), and adds to this reification the abstractions of the economist (e.g. game theory).As the neuroscientific and sociobiological examples indicate, the Reification Fallacy is often combined with other fallacies. In these cases, parts of a whole substance are first abstracted from it and treated as if they were substances in their own right (e.g. brain hemispheres, genes); and then a second, “Mereological Fallacy” (as Bennett and Hacker call it) is committed, in which what is intelligibly attributed only to the whole is attributed to the parts (e.g. the left hemisphere of the brain is said to “interpret,” and genes are said to be “selfish”). [...]The irony is that while New Atheists and others beholden to scientism pride themselves on being “reality based,” that is precisely what they are not. Actual, concrete reality is extremely complicated. There is far more to material systems than what can be captured in the equations of physics, far more to human beings than can be captured in the categories of neuroscience or economics, and far more to religion than can be captured in the ludicrous straw men peddled by New Atheists. All of these simplifying abstractions (except the last) have their value, but when we treat them as anything more than simplifying abstractions we have left the realm of science and entered that of ideology. The varieties of reductionism, eliminativism, and the “hermeneutics of suspicion” are manifestations of this tendency to replace real things with abstractions. They are all attempts to “conquer the abundance” of reality (as Paul Feyerabend might have put it), to force the world in all its concrete richness into a straightjacket.
I find this interesting in the way that smart people are likely to disagree with the correct interpretation of some of its claims - while others would say the post is worshipping the mysterious, others would say that it's just making reasonable cautions about the inherent methodological limitations of a certain approach. One might even think that it's essentially making a similar point as Eliezer's warning about floating beliefs, and therefore to agree with the Sequences. The caution of "beware of thinking that your abstractions say everything that there is to be said about something" is a reasonable one, and people do clearly make that mistake sometimes.
I expect that part of what influences how plausible one finds this argument depends on whether one has more of an "engineer's mindset" or a "philosopher's mindset". Somebody with an engineer's mindset will think that "yes, the abstractions we use might be imperfect, but what else do you propose we use? They're still the best tool for accomplishing stuff, and anything else is just philosophcial nonsense that isn't grounded in anything". Whereas the philosopher is less interested in using their knowledge to "accomplish stuff", and more interested in the ideas and their implications themselves.
As an aside, this distinction might be part of the reason why we have so many computer or hard science folks on this site. Partially it's because Eliezer used a lot of CS jargon in writing the Sequences, but probably also because the Sequences, while philosophical in nature, are also very focused on practical results and getting empirical predictions out of your beliefs.
Looking at what we could use this distinction for (and thus taking an engineer's mindset) some people here have mentioned getting an "ick" reaction from religious people, just due to those people having strong false beliefs. I think that, combined with properly understanding the emotional basis of religion, an understanding of the philosopher / engineer distinction can help avoid that reaction. Our values determine our beliefs, and there are plenty of religious people who aren't stupid, crazy, or anything like that. They might simply be philosophers instead of engineers, or they might be engineers who are more interested in the instrumental benefits of religion than the rather marginal benefits of x-rationality. (Amusingly, such a "religious engineer" might justifiably consider our obsession with "truth" as just an odd philosophical pursuit.)