April 9, 2005

"Is there a thesis of Determinism?"

He asks, while birds most likely chirp.

I will be giving a talk in Metaphysics soon (not this week but next). I will be discussing, among other things, P.F. Strawson's essay, "Freedom and Resentment" (http://www.ucl.ac.uk/~uctytho/dfwstrawson1.htm).

I wanted to start this week by throwing out some teasers of what I will be talking about. Getting some early feedback will be helpful in getting me prepared and in anticipating possible concerns.

Early on in “Freedom and Resentment” Strawson says,

“Some philosophers say that they do not know what the thesis of determinism is. Others say, or imply, that they do know what it is. Of these some—the pessimists, perhaps—hold that if the thesis is true, then the concepts of moral obligation and responsibility really have no application, and the practices of punishing and blaming, of expressing moral condemnation and approval, are really unjustified. Others—the optimists perhaps—hold that these concepts and practices in no way lose their raison d’etre if the thesis of determinism is true. [ . . .] If I am asked to which of these parties I belong to, I must say that it is first of all to the party of those who do not know what the thesis of determinism is.”

Since Strawson does not make much of this point (I used to just read it as a coy nod to ordinary language philosophy’s scruples), I want focus this post on this question—that is, on whether there is a thesis of determinism that is intelligible, well-motivated, and substantive. By “substantive” I mean a thesis that gives us reason to believe we are discussing what the actual world, in its most general aspects, is really like—that is, whether determinism is telling us something true about the world we experience on a day-to-day basis and explain via our best science.

One fairly standard way of construing the thesis of determinism is as follows:

“Consider now the existence of certain events governed by natural laws. It appears as if any such events must occur. Given a prior state of the world that is governed by laws of nature, a unique state of the world is forthcoming. It is helpful to think of the laws of nature operating as mathematical functions and the antecedent events as arguments for these functions. Once the function and the argument (input of the function) are settled, the output is necessitated. To implement the mathematical analogy, let f(x) = 5x + 2 and the input of the function be 3. The output of f(3) is 17, a mathematically necessitated result relative to the function and argument. Just as any other result is mathematically impossible—a violation of the laws or rules of mathematics—any event other than the one that actually occurs, relative to the antecedent state of the world and the laws of nature, is naturally impossible. Only by supernatural interference could an outcome other than the actual one occur in a world with the identical prior state and laws. Determinism can then be defined as claiming that it is logically impossible that there are worlds with natural laws and pasts congruent with the actual world and yet with futures distinct from that of the actual world.”

Mark Bernstein, “Fatalism,” Oxford Handbook of Free Will, p. 68

This kind of thesis of Determinism might be called a thesis of Global Determinism. It works as follows:

(1) Start with any possible world W whose causal order is structured by laws of nature. (Assume, for the time being, that the concept, ‘laws of nature,’ is coherent and we know how to construe it. Laws of nature, according to this construal, would operate like mathematical functions in Bernstein’s sense: taking definite inputs as arguments, they would produce definite outputs).

(2) Assume that at some of level of description there are structurally homogeneous, basic particulars in W out of which all complex objects and relations in W are composed (we can assume, to make it easier to imagine, that these particulars are physical, but they need not be to carry through the argument). A definitely describable system of relationships among all of these particulars at some time t is a ‘Global Event.’ Global Events are the “arguments” upon which the laws of nature do their computational work. In the worlds in which these particulars are physical, we can assume that the character of a Global Event will be given by a complete description of the spatio-temporal arrangements of basic particles in fields of force (or whatever our best science tell us is the best idealization of a Global Event).

(3) Conclude that, in any such world W, the laws of nature must compute, at t, only one possible future (one future Global Event at time t2 ).

The reason this is “Global Determinism” is because what the thesis is quantifying over is worlds:

(GD): There is a world W such that if (1) and (2) are true of W, then (3) is also true of W.

If the actual world satisfies GD, then we live in a deterministic world. Do we have any reason to believe we live in a deterministic world? We certainly deliberate and make choices as if there were alternative possible futures, so at first glance we do not act like we believe that GD is true. Are we simply massively self-deceived?—believing one thing in the philosophy classroom (or the physics laboratory) and another in ordinary practical life.

I think the best way of approaching this question is to ask: does the thesis of determinism make sense of the phenomena that our best scientific and common sense theories (including ordinary psychology) explain?

Bernstein’s analogy between laws of nature and mathematical functions is helpful, if massively deceptive. The kind of function that could map a Global Event is, to say the least, slightly more complicated than a one-variable, two-term algebraic equation.

I am sure that those savvy with the computer science, mathematics, and physics involved can help me out, but it would seem that the orders of magnitude involved in computing a state description of the world or ‘Global Event’ would quickly lead us to, at best, intractable predictability problems and, at worst, paradoxes of infinity.

But let’s be philosophers about this. Sure, what we imagine here is impossible for us, but not for an Omniscient Mind or Super-Laplacean Computer. The issues I am raising are a problem for epistemology, not analytic metaphysics. Verificationism died a long time ago. Let it rest in peace.

Ok, so now we are relying on another concept, ‘Omniscient Mind,’ to make sense of the thesis of Determinism (at least in its ‘Global’ variety). Unlike us poor souls, the Omniscient Mind knows that the actual world is composed of basic particulars, knows the number of and relations among these particulars, and knows the function that computes Global Events in our world.

But wait? What use does an Omniscient Mind have for a function? It knows everything, after all. Presumably, it knows the future before it happens. Presumably, the concepts of past, present, and future are useless to it (as well as any computations among them). The Omniscient Mind just looks at the whole of space and time and absorbs it in one gulp.

But wait, what is the Omniniscient Mind 'looking' at? Whether or not the world has a beginning and/or an end in time and space is presumably just an ‘an empirical issue.’ Space and time might be infinitely ‘self’-contorting manifolds. So what would there be for an Omniscient Mind to ‘look’ at? ‘Looking’ implies figure and ground, things that come before consciousness and things that move to the background. But there could be no such definite perspectival structures in the scenario we are imagining: it would just be one inifinite series of one damned indistinguishable thing after another.

These problems are not new (I first encountered them, I think, in Sister Regina’s fourth grade class as we debated whether God can square circles or create rocks he cannot move).

We started this discussion of Determinism by worrying about whether our best beliefs about the ‘world as it is in itself’ might threaten the world as it looks to us when we deliberate in practical life. And yet, it turns out the world as it is in itself is not something we have a firm grip on. We have helped ourselves to some half-formed metaphysical concepts—‘Global Determinism,’ ‘Omniscient Mind,’ ‘Laws of Nature as Mathematical Functions’—but then, as we actually examine how to cash out these shibboleths of our philosophical fancy in precise terms, we quickly lose our grip on the concepts. Better to end where we started--that is, with what we knew perfectly well before we started philosophizing in the first place: that we live our lives by imagining possible futures, deliberating about which among them would be the best, and acting so as to realize as our choices (except when we are weak willed).

The metaphysical question at issue is what kind of world makes this notion of freedom intelligible and whether or not we are justified in believing we live in it; the question is not whether some fantastic thesis of Global Determinism threatens it.



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