If we start replacing bits and pieces of him with prostheses and implants, at what point does he cease being Sean? Where is the Sean nature? In the fingers he types with? In the larynx he uses to speak? In his brain?

At what point does bionic-Sean stop being a human being? Suppose we give him artificial kidneys and a synthetic liver to go with his new heart. Is he still human? Should he still be treated as human under the law? What would *he* say?

What if we replace everything *but* his brain? Still Sean? Still human?

Does it matter when Sean has bits and pieces of him replaced? Is Sean’s-brain-in-plastic as human as a foetal brain transplanted into an artificial (and perhaps very non-bipedal-looking) body and grown into adulthood a human?

What about the elephant? Is a bionic elephant still an elephant? What does adult-elephant-in-artificial-body think about things? Would it find natural elephants attractive? What would a very young elephant brain raised in a non-elephantine body think about things? Would *it* find natural elephants attractive? (Cats raised by humans totally isolated from all knowledge of other cats still try to mate with other cats; likewise, cats and dogs raised in environments where they encounter all manner of other animals regularly sometimes try out a bit of forbidden dog-on-cat love. See youtube…)

We could go further and start augmenting brains, or perhaps even completely replace them: record all the memories of a person and “restore” them on compatible hardware — another brain, or a brain with electronic enhancements, or perhaps something entirely artificial. When you woke up after the procedure would you think you were less you than if it was “merely” a heart replacement surgery?

Reductionism is a useful tool in understanding how elephants and humans lay down their memories, and in understanding how to replace the various organs that feed those processes in the brain until they can be sufficiently replicated in some other medium. “What is a memory?” and “What is a personality?” are questions answerable in Sean’s “sensible reductionist perspective”.

WE JUST HAVEN’T ANSWERED THOSE QUESTIONS YET.

The lack of complete answers is not a reasonable condemnation of a reductionist approach. You would have to argue that those answers cannot — even in principle — be found in examining the components of the brain and its environment (the organism and things outside that).

“Sensible repackaging” — abstraction — is convenient both when the underlying mechanics are extremely tedious to work with and when there is actual theory choice because the underlying mechanics are not fully known. Indeed, an abstraction that is in very very close agreement with observation in some useful limit is also a powerful tool for verifying underlying theories. If your “micro-physical” theory cannot in principle reproduce “molecule”, “organelle”, “eukaryotic cell”, “organ”, “elephant”, and “herd of elephants” then it’s wrong. However, it’s reasonable that you can’t recover all of that *yet*.

Sean wrote: “nobody thinks that the right approach is to break a giraffe down to quarks and leptons and start cranking out the Feynman diagrams. (If such people can be identified, I’d happily join in the condemnations.)”

Is that a permanent objection? If at some point the ability to compute the evolution of a system of quarks and leptons of an object the size of an elephant and its immediate environment arises wouldn’t it be a useful tool for predicting the future actions of that particular elephant?

Obviously we can’t do this now and almost certainly won’t be able to in the next couple of years.

How about something that’s the scale of a prion or a small virus? Or a prokaryotic cell? Or two neurons? Do you condemn anyone looking below the level of molecules and atoms for objects of those scales?

you write
>A sensible reductionist perspective would be something like “objects are completely
>defined by the states of their components.”
but this makes no sense already for an atom.
There is no quantum state of each component, only a state of the whole thing.

As for the elephant, remember the no-cloning theorem.

Of course, everything is ultimately quantum-mechanical; the question is whether quantum mechanics will appear directly in the theory of the mind, and not just in the deeper-level theories like chemistry on which the theory of the mind will be based. Edelman and Penrose might be right about this, but I doubt it. It is precisely those systems that can be approximately described by pre-quantum classical mechanics that are so sensitive to initial conditions that, for practical purposes, they are unpredictable.

One of the implications of this point is not only that biology-as-theory is not necessarily reducible to physics-as-theory, but that maybe you couldn’t ever run a giant physics simulation of something as complex as a brain and hope to learn anything predictable, because of the sensitivity to initial conditions.

Regarding the reducibility of the elephant to its components, I think the response that it depends on the environment is a valid response. Its more clear in the case of the protein folding- one can’t answer the question by just discussing the components, one needs the environment also.

As Dupre says around 34:40, he thinks this is the heart of the argument. Some systems are well understood with reductionism, and some are not. In particular, those that don’t depend much on their environment, can be usefully analyzed in terms of their components.

The other interesting point for me is about the difference between physics and physicalism. And the attempt of physics to call all explanations somehow a part of the science of “physics” is a kind of imperialism (43:43). You usually have to change the question a bit before its posed in the form of a physics question. When Sean says the reductionist statement is “objects are completely defined by the states of their components.” this says that we can basically only talk things that are internal to a given thing. Dupre is saying that when we talk about stuff- the concepts we apply to them are often relational qualities. An elephant may be called “friendly” for example, and that may depend on the other elephants around.

It’s become increasingly clear over the past few decades that any system can be derived from physics, if you have a big enough computer.

This is the position that can legitimately be opposed by anti-reductionism, I think, and also gives physicists who espouse it a bad reputation. First, the “if” is an unrealistic if. And there are some problems where the complexity or speed of the algorithm means the “big enough” computer is of extraterrestrial dimensions.

Second, biology, chemistry and physics are systems of knowledge. They happen inside people’s minds. The biological, chemical, physical phenomena are real, but the organizing principles we use to describe them are mental. In that sense, you don’t derive biology (as a system of knowledge that abstracts biological phenomena) from physics (another system of knowledge, which is compatible with but does not subsume biology). You can use a simulation of physical phenomena to predict biochemical phenomena, but you aren’t reducing laws of biology to laws of physics.

After all, even in physics, running a giant simulation doesn’t necessarily yield useful organizing principles; you need some way of abstracting the output into a simpler general principle.

Please tell me what space is made of then. I like to make some.

Phil Anderson, one of the most prominent anti-reductionists, had something very concrete to object to. He testified before the Congress against funding the SSC.

Pls explain “obviously”

Regarding anti-reductionism, you might find this interesting:

Infinity really is different, rspt the paper it is about: More really is different

Now imagine a world whose micro-states are grouped into disjoint macro-states P[1], P[2], P[3] etc. Suppose one of the laws of the macro-world is: if the world is in macro-state P[n] it will proceed to macro-state P[n+1]. Reductionism requires this law should emerge from a deeper law; i.e. there should be a transition function T on the micro-states such that if the world is currently in a micro-state S that’s an element of P[n], then it will proceed to the micro-state T(S) which is in P[n+1]. If there were such a transition function from which the macro-law emerges, then one could use it to recursively define a choice function F on the family of macro-states; i.e. let F(P[1]) be any member of P[1], and let F(P[n+1]) = T(F(P[n])). In other words: the Axiom of Choice (at least this version of it) is a consequence of reductionism!

Without the Axiom of Choice reductionism might fail.

“I think that some philosophers have thought along those lines, but it’s not common. A good number of them believe strongly that space is fundamental.”

The idea that space is not fundamental is common in Indian Buddhist philosophy. I’m not going to inventory the opinions of all schools of Indian philosophy but what comes to mind, off the top of my head…

The first systematic form of Buddhist philosophy is called Abhidharma. It came into existence in India sometime BCE but the exact chronology is difficult to establish. The Abhidharmists agreed on general lines of method but disagreed on details. One major group, the Sarvāstivādins posited two theoretical entities which relate to what we normally talk about as “space”:

- space (ākāśa)

- the space-element (ākāśadhātu)

They held that things like table, people, houses, cows are all composed off obstructive atoms of matter. The space-element was their explanation for any opening, expanse, empty region between the solid material things. So in a room, the walls, roof, floor are all made of obstructive atoms. However, the middle of the room, the space is composed of the space-element which is also atomic but non-obstructive. (By the way, I’m not aware of any discussion of space-element being specifically a gas.)

Now, space (ākāśa) is not the same as the space-element (ākāśadhātu). The space-element is matter so it is displaced by other matter but space is immaterial. The Sarvāstivādins hold that space pervades all entities which enter into any spatial relationship. It is the necessary element which allows for any kind of spatial relationship to occur. It is equivalent to the idea of a container space in which things happen.

Now, two groups of Abhidharmists reacted to the Sarvāstivādins: the Dārṣṭāntikas (which existed by at least the 2nd cent CE, probably earlier) and the Sautrāntikas (their major comprehensive work composed in the 5th century CE). Both held that space (ākāśa) is not an actual element of reality but just a way of speaking. They did not deny the space-element (ākāśadhātu), which is matter which can be obstructed by other matter but does not itself obstruct other matter. However, space, which is wholly immaterial, does not obstruct and is not obstructed, has no reality for them. So they denied the idea of a container space.

To briefly talk of other groups, the Madhyamakas also deny that space is a fundamental element of reality. Same for the Yogācārins, who based some of their ontology on the Sautrāntikas. Overall, the idea that space is not fundamental is common in Indian Buddhist philosophy.

(And time is fundamental to only a few Buddhist philosophers. The majority opinion is that it is not fundamental. It does not appear as an element of reality for any of the groups mentioned above.)

I think that quantum mechanics is evidence that good science does not have to be single mindedly reductionist in its approach, and I have ocassionally wondered how one might go looking for new high level phenomena occruing in large collections of particles.

But the most direct example is something like AdS/CFT, which makes the “space is not fundamental” point about as directly as you can imagine.

(To get an intuitive picture of this, one has to first realize that the fundamental object of QFT is a quantum field, and point-like particles are a derived object, which is not always all that useful. But, this is a conversation for another time.)

@7:
I don’t know where you got the idea that computers accurately simulate protein folding but it is completely false. The most sophisticated modeling programs struggle with even simple proteins and the results are very crude and unreliable.

Furthermore those programs are mostly based on empirical measurements and huge libraries of already empirically determined protein structures, actual physics plays relatively minor role so they certainly fail as examples of “biology derived from physics.”

Now, I am not saying that it is impossible in principle, only that it hasn’t been done so far and won’t be done in the near future.