If reductionism is the hammer, what nails are out there?

Gender/sexuality. People really want essences here. Some people are still stuck on "male essence / female essence", some manage to get as far as "attracted to male essence / female essence". Reductionism could (dis)solve this issue.

I have been vaguely thinking of writing a top level article about psychological essentialism for a while, but this seems like a good place to just point to it. There is a large body of research on the subject and the best summary of it I know is Susan Gelman's "Essentialism in Everyday Thought".

The process of imputing causation to visible characteristics from an unseen inner variable seems to be something humans subconsciously and automatically do in some situations. You can do studies of essentialist reasoning in children by asking "Suppose an X was raised by Ys, in case C would the X tend to do this X-ish things or this Y-ish things?" Very young children will give different answers for difference values of C, and in some cases (like with human language) they are clearly wrong which makes it seem like maybe they are executing a domain specific "complex essentialist cognitive module" rather than reasoning from observed evidence.

If you want to see some back and forth on the subject instead of just taking one author's word for it, here is a 1993 criticism of the essentialist research program by Susan Jones and Linda Smith and a rebuttal by Susan Gelman.

My impression is that essentialist cognition is enormously common because it is enormously useful. There is an essence for ducks and its called the duck genome. Hypothesized essences have been mapped to one or more physical mechanisms so often that mostly I just assume that this can be done for all essences that are coherent. The mechanisms generally have approximately the pragmatic properties normally ascribed to essences (like immutability) but it doesn't match human intuitions perfectly because, whether its a democracy or an ecology or a painting "it's just an arrangement of atoms, right?"

After I internalized this view of the world, I gained a measure of sympathy for people who believed in supernatural theories because those situations became intelligible to me as people having working models for reality using the built in tools of human reasoning. "Evil ghosts in the swamp" model "malaria" well enough to explain why to avoid swamps while looking for food. "God" models "inscrutable optimization processes stronger than me" enough to help people make a kind of peace with the fact of limited power and explain the appearance of order in the world while looking for food.

When I need to "argue past the essence" without giving the whole cogsci backstory I try to point out the "magic sparks" buried in the theory and then denaturalize the sparks by hypothesizing vaguely realistic complex mechanisms in their place. Like sometimes people deploy the concept of IQ as working like a magic spark that is more or less bright, and you can denaturalize it by breaking it into pieces that can obviously vary independently like working memory capacity, vocabulary acquisition, "good nutrition, good sleep, and the time to cultivate your mind", and so on.

But most of the time, a theory with a spark is perfectly good for making the predictions you need to avoid scary situations and find food. I would expect an AGI worth its salt to have some internal mechanism that functions roughly to "notice the sparks" and use them as appropriate and push deeper as dictated by opportunity and need :-)

For example, I had lunch the other day with a physics professor from a good university who thought that, even if we could assemble an atom-for-atom duplicate of a person's exact physical state, it might well not act like a person for want of a soul.

...a PHYSICS PROFESSOR??

That makes my head hurt.

And that makes me realize that, after all this time reading LW and OB, I must still be overestimating academia. Consider me updated.

If reductionism is the hammer, what nails are out there?

If you're doing the reductionism right there is probably only one nail out there! ;)

Hunger. People go on diets, notice that the diets leave them hungry, and fail to take the next step and determine which of the body's half-dozen hunger mechanisms is being triggered first.

• Anticipated experience

What about ethics? It seems that many people think there is some 'moral bedrock' somewhere -- but is there really such a thing?

To me it seems that ethical questions are really about the tension between our knee-jerk moral intuitions and ethical frameworks (utilitarianism, deontology etc.). Increasingly elaborate theories are built out of the urge to somehow make our 'moral compass' seem logical, until someone comes up with some clever example where the theory somehow conflicts with our intuitions...

I know moral relativism is not universally popular, but can reductionism/rationalism lead to anything else?

Essentialism seems to me to be more general than anti-reductionism. One can be a reductionist essentialist.

I take essentialism to be the view that there is a privileged classification scheme that applies to all things in the world, and that the position that a thing T occupies in this scheme is entirely determined by whether T possesses a certain package of essential qualities. All other qualities of T are accidental.

Thus, to determine whether T is an X, you just need to run down a checklist of qualities x_1, . . ., x_n and see whether T has all of them. The classification scheme is unambiguous; if T doesn't have one of the x_i's, then T is an altogether different kind of thing.

Furthermore, these essential qualities aren't exceedingly exotic. Having every arrangement of atoms be a different essential quality wouldn't count. The classification scheme that the essential qualities induce is well-approximated by the classification scheme that we use in everyday life. For example, the true classification scheme should include categories that closely align with our concepts of living vs. nonliving and male vs. female.

In practice, this means that things are best thought of as a bundle of essential qualities, plus a diff of accidental qualities. Good practical and ethical reasoning focuses far more on the essential qualities than on the accidental ones.

But taking this view doesn't rule out being a reductionist. You could be an essentialist while still believing that to have essential qualities x_1, . . ., x_n means to have the arrangement of your atoms be in a certain set of possible arrangements. You would just hold that, for whatever reason, the possible arrangements of atoms can be classified with a scheme of the above sort.

Eliezer's sequence on words is a good antidote to this kind of thinking.

Another large category of essences: Perception of all sorts, not just pain. Computer scientists have found out the hard way that vision doesn't just happen.

(7) is a hard one. I think it was G.K. Chesterton [1] who said that seeing through everything is indistinguishable from being blind.

You're using the standard of the universe as scientifically postulated (interacting matter/energy which can be understood through observation, experiment, and logic) as the tool for dissolving essences.

I suppose the risk is thinking that the universe assuredly is as currently conceived, and may not be a great deal weirder than that. On the other hand, unless it's got a whole other layer of currently unimaginable weirdness, we're still limited [2] to observation, experiment, and logic in investigating it.

[1] I realize that citing Chesterton makes the statement less credible, if anything, but I think it's a legitimate point as well as clever, and I''m giving credit where it's due.

[2] I'm inclined to think that if there is a great increase in processing capacity, there will be emergent qualities as unimaginable to us-now as formal logic is to an earthworm, but there's no point in putting much thought into what the details might be.

When you make an effort to minimize or eliminate your belief in essences, how does it affect your life?

• Talent/Intelligence

Why it's tempting to postulate an essence: people seem to be good at different things, and for any particular thing, some people are better than others; and since we can't read others' minds, and people aren't always skilled in introspection and explanation, it's not always easy to find out what they know that we don't.

• Aesthetics/"Taste"

Why it's tempting to postulate an essence: people have different "tastes", and it's difficult to argue them into changing their mind about what they like. Plus, people aren't good at introspecting to discover via analysis why it is they like what they like, and are motivated not to do so because they're afraid they won't like it anymore (similar to the way people fear physicists' reduction of rainbows). Plus, shared tastes are a common criterion used to divide people into tribes.

• Music Theory

Why it's tempting to postulate essences: certain periods/styles exhibit empirical regularities not shared by other periods/styles, and cataloging these regularities is felt to be most of what the subject matter consists of. The discipline doesn't have a culture of reductionism, perhaps because irreducible "talent" (see above) is already assumed among those studying it, so there's no need to systematically address the question of how to make music from non-music, or how to invent new styles. Also, people can sense that treating such questions systematically would involve difficult new abstractions, in contrast to the concrete concepts used to do cataloging, and they run away in fear.

There are no magical essences, but there are many unexplained things. I'll go so far as to claim that if you have really internalized LW's reductionism lessons, you should be seeing mysteries everywhere you look!

It is one thing to say "duh, this thing is built out of these tiny blocks". Feynman gives an example in his lectures (I have no idea if it's still true today, or if it just reflects Feynman's state of knowledge about physics): all attempts to derive ferromagnetism from the behavior of individual atoms, at the time Feynman was writing his lectures, gave the result with the wrong sign. Can you believe that? All physicists at the time assumed that the complexity of the situation - lots of tiny spinning charges interacting - should somehow make the correct sign emerge, if you "do all the calculations right". Now does this remind us of anything, hmm.

It's easy to note that something can in principle be built out of smaller building blocks, but much harder to explain how it was built. Do actual work, figure out the mechanism, like I tried to do in reducing "could".

For example, do we really know anything about "personal identity" in the presence of copies? Can we build "personal identity"? Given a computer program that runs multiple copies of a person, can we make correct statements about the "subjective anticipation" of these copies? Which forms of anthropic reasoning work, and which don't? Does the doomsday argument work? Many people hold strong opinions, but there doesn't seem to be any definitively correct solution.

All the other examples on your list have the same problem. We cannot reduce mathematics - we don't even know what a natural number is! (Which means we can't teach it to a computer.) Reducing pain qualia - or "intelligence", say - is likely correspondingly harder.

Edit: made tone less confrontational. Apologies if you read my comment before that.

I have no idea what an essence is supposed to be. I guess that's why I'm having a hard time to understand your post.

If there's one set of physical laws that determine everything, isn't that a kind of essence?

On 7.: even if you were to successfully show that the real world reduces to some lower, possibly more/less complicated, level (as particle physics did, and nuclear physics did, and, well, physics really likes doing...) that next level is still "the real world" just understood in slightly more detail.

Which you can then try and reduce further. (I really hope it's infinitely complicated :p)

In addition; 1-5 are all aspects of seven. So I'm really not sure what the point you're trying to make.

What about the nails scattered around here http://lesswrong.com/lw/oh/righting_a_wrong_question/ ?