Thank you.
I did think of something like that, but as you said, in a certain sense it only pushes the question back one step… Is our understanding of how to classify things really based only on intuition?
Can it be argued that this fallacy is actually a significant argument in favor of strong emergence?

I can’t come up with a general definition, and it seems to me there isn’t one. Intuition is indeed helpful here, as it is everywhere else. Even if you had a definition, it would be nothing more than a description of your intuition. That doesn’t materially change the situation.
I’m not familiar with the term “fallacy of composition,” though I understood from you that you mean the assumption that the characteristics of the components necessarily also characterize the composite. I don’t see here even the slightest argument in favor of strong emergence. At most, this is just a description in different words of the assumption of emergence itself (not necessarily strong emergence. Your weight example is plainly a case of weak emergence), not an argument for it. Strong emergence is not really relevant here at all.

Hello Rabbi,
I think the claim that the fallacy of composition works in favor of strong emergence is quite clear.
After all, strong emergence claims that there can be phenomena that exist at the macro level which do not exist at the micro level, and yet they are not derivable from some sum (and so on) of micro-level phenomena.
That is exactly the fallacy of composition: a property can belong to an individual element and not appear at the level of the whole.
For example, the claim that each brick weighs little and therefore the whole wall weighs little is a mistaken claim and fails because of this fallacy.

The same idea exists in strong emergence. For example, those who claim this regarding consciousness say: the fact that each neuron lacks consciousness does not mean that consciousness will not appear in the sequence or collection of all the neurons together.

I’ll explain again.
1. The fallacy of composition is not an argument in favor of emergence; rather, it is itself asserting emergence. Just as the law of gravity is not an argument for the phenomenon of gravity but simply a description of it. In other words, someone who accepts emergence will not see composition here as a fallacy. So what argument is there here?
2. The weight of a wall as opposed to a collection of stones is a poor example, because that is weak emergence. The heavy weight is the sum of the light weights, so the macro property is explained by the micro properties. The question of whether there is strong emergence concerns macro properties that cannot be reduced to the micro at all. That, and only that, is what the dispute is about.

2. Right, that really is the opposite kind of example…
1. I didn’t understand what you mean when you say that it is itself asserting emergence. Someone who accepts strong emergence will accept the claim that this is a fallacy, just as someone who speaks about weak emergence would. So I didn’t understand the distinction.
B. How can one not see this as a fallacy? Empirical tests show this quite easily…

1. Exactly. And that is why the fallacy of composition adds nothing to the discussion. You are raising claim A in support of claim B. But if only someone who accepts B will accept A, then what have you gained? Especially since A is nothing but a different formulation of B.
B. In weak emergence this is indeed empirical (and also trivial—who disputes it?). But regarding strong emergence, I explained in my book that there neither is, nor could there ever be, an empirical test that would show strong emergence. And that, after all, is the only issue under discussion here. “Fallacy of composition” is just a fancy term for something trivial or incorrect.