Friday, February 15, 2008

E2.0: Stuart Kaufman: Function, Agency, and Reductionism

This is the 16th in a new series of weekend posts taken from the presentations at the Salk Institute’s “Beyond Belief: Enlightenment 2.0.”. I have placed an index of essays in this series in an introductory post, Enlightenment 2.0: Introduction.

In this post I look at the presentation of Stuart Kauffman. Kauffman’s presentation concerned the possibility of reductionism – the idea that any event in nature can be understood in terms of reducing it to statements ultimately in the realm of physics. The idea is that if you knew all of the relevant physical facts about all of the objects in the universe, you could account for everything that has happened or will happen. There is nothing ‘outside the realm of physics’ that we need to consider.

Kauffman denies this claim. He holds that there are things in the universe that cannot be reduced to pure physics.

I am going to admit at the start that I do not have the knowledge to evaluate Kauffman’s whole argument against reductionism. However, I can argue that in a couple of steps he takes along the way – steps having to do with value – he stumbles, and gets the facts wrong. This does not imply that he cannot make his argument work after correcting these mistakes, but they are mistakes nonetheless.

One of the examples that he gives for things that cannot be reduced is ‘function’. He speaks specifically about the function of the heart. The function of the heart, he says, is to pump blood. Hearts also make heart sounds, however the ‘function’ of the heart is not to make heart sounds.

Already this is interesting because it says that the function of the heart is a subset of its causal consequences. It’s the pumping of blood, and not the making of heart sounds. And that means that in order to analyze the function of the heart you have to know the whole organism and its selective environment and probably its selective history.

Here, I will assert that Kauffman is guilty of an important omission. Another thing that one must know before one can answer the question of, “What is the function of the heart?” is “What are the interests of those who are asking the question?”

Kauffman speaks as if the “function” of something is an intrinsic property – that the question has a meaningful sense that is independent of the interests of those asking the question. If it did, then ‘function’ would be a property like ‘mass’ or even ‘distance from’. It makes sense to talk about the mass of an object, or its distance from something else, even if there were nobody around to measure it.

But nothing has a ‘function’ unless there is somebody, at least hypothetically, who has an interest who is asking the question. We then answer the question, in part, by asking and answering the question, “What interests are we assuming for those who are asking the question?”

It turns out, when speaking about hearts, the ‘interests’ that most of us have in mind is survival. The question, “What is the function of the heart?” means “What is it important to us to have the heart keep doing?” We do not care whether the heart makes heart sounds, so making hearts sounds is not its function. We do care if the heart continues to pump blood, so this becomes its function.

If, per chance, the pumping of blood produced results that we simply had no reason to care about, but the heart sounds produced effects that were vitally important to us, then the making of heart sounds would be its ‘function’ – it would be the thing that we wanted the heart to keep doing.

Kauffman wants to explain function in terms of “Why did the heart come into existence?” However, ‘why’ questions inherently ask about an end or a goal. We can ask, “Why did the Earth come into existence?” Without an end or goal or purpose, there is no answer.

However, ends or goals or purposes themselves require interests or desires. A ‘desire that P’ identifies any state of affairs in which ‘P’ is true as an end or a goal of human action (or, at least, human attention). Remove all desires, and ends or goals disappear. When ends or goals disappear, “Why did this happen?” becomes a meaningless question. “How did this happen?” is still an important question, but not “Why?”

This is part of the reason why Kauffman is necessarily going to fail to reduce ‘function’ to physics. He is missing some of the necessary components of ‘function’ – the interests of those who are asking the question.

However, this simply pushes the question over into another realm. Can ‘interests’ be reduced to fundamental physical properties? Atoms do not have ‘interests’ – atoms do not care one way or another about what they are doing. So, how do we take ‘interests’ (or ‘desires’) and reduce them to statements about atoms (or something more basic than atoms)?

Kauffman addresses this question directly, under the title of ‘agency’ – another property that he claims is irreducible.

Agency is real. With agency . . . all sorts of things happen. For example, doing enters the universe. I am giving a talk. . . . Doing, meaning, value, purpose enter once there’s agency.

Kauffman than asks for the “minimum physical system for which I am willing to ascribe agency.” The answer he comes up with is that bacteria swimming up a glucose gradient are agents and rocks are not.

I think an agent is something that can reproduce molecularly and has to do at least one thermodynamic work cycle.

I think that this account of ‘agency’ is absurd. Agency requires the capacity to act on beliefs and desires. An agent is doing something when it is acting to fulfill its desires, given its beliefs. A particular state has meaning or value for an agent to the degree that propositions that are the objects of its more and stronger desires are true in that state. There is a purpose when there is a proposition P that is the object of a desire to be made true.

Bacteria do not have desires.

Like Kauffman, I do not know exactly what marks the point at which desires come into existence. I am willing to say that humans and many higher-level animals have beliefs and desires. I would say that beliefs and desires require a computational network – in other words, a brain. Cells are not agents. Their lives have no meaning, value, or purpose to themselves, because cells are incapable of having desires.

With this, it is still open to question whether agency (or beliefs and desires) can be reduced to physics. Since I take beliefs and desires to be functional states, the question can be translated into one of whether functional states can be understood in terms of physical states. Can we reduce a for-next loop, or a programmatic subroutine, into a set of physical statements?

The question of whether we can or cannot do so is outside of my scope of expertise. In this essay, I will not pretend that I have an answer to this question. However, I will argue that it makes no sense to seek an answer to the question until we make sense of the question.

Kauffman’s question needs some careful modifications. We need to recognize that the ‘function’ of something has to do with interests, and that ‘agency’ depends on computational states such as beliefs and desires. Once we make these changes, are there reasons to believe that these things cannot be reduced to physical states?

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