I read Popper’s The Open Universe for the first time yesterday. What do you think of Popper’s arguments against determinism, especially the metaphysical variety?
Although I appreciate Popper’s critique of “scientific” determinism, I confess to assuming that some kind of metaphysical determinism is true, and I found little in Popper’s words to dissuade me of that position. Unfortunately, I was unable to read the entire book. However, I plan to return to it soon, and so perhaps Popper will convince me yet.
Given Popper’s indeterminism, one issue that confuses me is the truth status of propositions about the future. Normally, Popper would say that a proposition is true when it corresponds to the facts, but what can a proposition about the future correspond to if the future facts are indetermined? Perhaps this is just a minor quibble, but it was a nagging question in the back of my mind while reading.
In any case, what do you think of Popper’s indeterminism? Have you been convinced?
I haven’t read the book. What’s he say?
In any case, physics is deterministic across the multiverse as far as we know. But that has nothing to do with free or morality, which have never made claims about physics.
Hi Elliot,
I hadn’t expected any contibutor here but me to have not read Popper’s critique of determinism!
In The Open universe, Popper comes out firmly against all forms of determinism, even in physics. He is a thoroughgoing indeterminist. Primarily, his critique is directed at “scientific” determinism, i.e. the assumption that, with complete theoretical and factual knowledge of any particular moment, the future can be predicted with absolute precision. For Popper, although the past and present may limit possible future events, the future is not implicit in the past.
“Scientific” determinism is stronger than metaphysical determinism. Metaphysical determinism does not require that the future be derivable from the past (with complete theoretical and factual knowledge or otherwise), but merely claims that future events, in a sense, already exist. Since “Scientific” determinism is a stronger claim (i.e. can more easily be criticised), Popper spends the lionshare of his time, at least in the first half of the book, critiquing that.
Let me put down some thoughts that might easily be dismissed by someone who knows more about this than me.
First, methodologically, Popper argues we should search for regularities. To the extent we find these, and they are true; these represent something that’s been determined. I guess you could awkwardly call this “methodological determinism”. But just because there is stuff out there that seems to be determined, does that mean that that is all there is?
So methodological determinism is important, metaphysical determinism isn’t. (In other words, search for regularities, but don’t presume that that’s all there is.)
The problem traditionally was thought of how do we go from a particular to a universal. That is how do we go from taking an observed instance and justify making a generalization of this. This appeared to be a really pressing and intractable problem — and still is to many people.
So, I’m guessing materialism or determinism and so on were formulated as possible ways to help explain how we go from particular to general. I don’t think they ever managed to adequately accomplish this but generally only pushed the problem back farther and probably only complicated it further.
Of course, Popper argues we don’t ever go from particular to general. That in a sense, it’s universals as far down as we can *see*. There are regularities out there to be seen, surly, but is that all there is? Why would anyone want to presume that?
What is the problem that metaphysical determinism answers?
It’s been a long while since I’ve read _The Open Universe_ but I guess one way to look at it might be like this; *metaphysical* determinism doesn’t readily solve any problem we are really concerned with, and not only that, here are a list of trivial (or not so trivial) problems we *create* by presuming it.
I mean, it’s fine to have problems, but do we want to create them needlessly?
>>Normally, Popper would say that a proposition is true when it corresponds to the facts, but what can a proposition about the future correspond to if the future facts are indetermined?<<
Is Popper saying *all* the facts are indetermined or only that some of them might be?
Matt,
Determinism is the theory that the laws of physics, given some initial conditions, always take it to the same state/result (say, 1 second later). You’ll have to imagine you could set up the same initial conditions again.
Another way to state this is you could perfectly predict the future, given perfect knowledge of the present, perfect knowledge of the laws of physics, and unlimited computational resources.
Or in other words, determinism says the laws of physics contain no randomness (or magic, or as-yet-unimagined other possibility).
Determinism should not be put forward as a theory in its own right. It’s just as aspect of the laws of physics. We can examine the laws of physics and note if they do anything random or not.
The current best understanding of physics is that it is deterministic (across the whole multiverse — events can look random if you don’t see the whole picture). That is an issue for physicists, not philosophers.
There is a second theory, also called determinism, which states, roughly, that people don’t make choices or have free will (or that morality doesn’t exist, which is about the same). This is sometimes confused with the first type of determinism, or thought to follow from it. This second theory is an issue for philosophers, as is the claim that it follows from the first determinism.
Sometimes people say we have fate or destiny and are ambiguous about whether they mean the first or second type of determinism, or both.
I don’t find the second type of determinism very interesting b/c I don’t believe any decent argument for it has ever been given.
I don’t see how going from particulars to universals, which is related to induction, comes into it.
Elliot,
>>I don’t see how going from particulars to universals, which is related to induction, comes into it.< <
I agree what I stated could easily be in error, at some point I'll try to explain this more fully so that the idea can be better criticized.
>>Determinism is the theory that the laws of physics, given some initial conditions, always take it to the same state/result (say, 1 second later). You’ll have to imagine you could set up the same initial conditions again.<<
To the extent we are speculating about the empirical world, isn’t what you are saying true about our expectations for *any* theory, not just physics. In what cases would we not expect to be able to take our theory plus initial conditions and arrive at the same results? (And then still regard the theory as true …)
Aren’t you just describing Popper’s necessary conditions for a theory to be falsifiable?
Consider the theory that when two photons collide there are two ways they can scatter, and which of the two happens is random with a 50% chance for each (the theory specifies both ways based on the trajectories the instant before the collision). That is falsifiable. And it’s indeterministic.
I don’t see anything wrong with that theory, except that it contradicts what we know about physics. (Photons can’t collide with each other at all).
I think that most scientists and philosophers would admit that the future is impossible to predict for most practical purposes. Some might think it would be possible to predict it in principle. I think Popper was right to pour cold water all over that idea and the way he did so was basically correct.
As for his metaphysical arguments. I don’t see how metaphysical indeterminism helps us to understand free will or morality. Also, there are lots of reasons to be uneasy about metaphysical indeterminism in physics. Quantum mechanics is commonly said to be indeterministic. I think this idea is badly mistaken and a lot more costly than many people seem to realise. If what happens after a measurement is that all of the possible outcomes are weeded out except one, then there are correlations among quantum systems that cannot be explained by any local influence from one system to another (EPR experiments) and on top of that whatever influence tells another system what to do also cannot be Lorentz invariant (Hardy experiments). So any theory that states that one of the possible outcomes happens is incompatible with basic principles of both special and general relativity.
http://cosmology.princeton.edu/~mcdonald/examples/QM/aspect_prl_49_91_82.pdf
http://arxiv.org/abs/quant-ph/0410160
The Everett interpretation, according to which the wave function describes how the world really behaves can be made both local and Lorentz invariant:
http://arxiv.org/abs/quant-ph/9906007
Finally, it seems to me that most indeterministic interpretations of quantum mechanics, including the statistical interpretation, are a lot vaguer than the Everett interpretation. In the Everett interpretation, you have one equation of motion for a system and you can say when one system becomes correlated with another, when the wave function acts in a manner that could give rise to probabilities and so on. In an indeterministic interpretation you have the Schrodinger equation or something and the collapse postulate and a very vague set of rules about when to use one or the other. A noble exception to this vague flummery is the Ghirardi-Rimini-Weber theory, which, although it suffers from all of the problems with non-locality and so on, at least gives a specific set of predictions.
Matt,
In my opinion, metaphysical determinism makes sense of propositions about the future (including universal propositions). For example, if the proposition “every swan is white” is true, then what is entailed about swans that have not been born yet? Does the universality of that proposition extend to all places at all times, or merely our particular frame of reference. If “every swan is white” does entail that unborn swans will be white, then how could it possibly be true in an indeterministic world? Since that portion of its logical content about the future cannot possibly correspond to the facts, in what sense can it be true? However, if metaphysical determinism is true, then talking about events that haven’t happened yet (from a particular point of reference) doesn’t run into any difficulty.
In any case, metaphysical determinism does not preclude the appearence of indeterminism, i.e. there could still be events which are scientifically unpredictable. I also like and agree with your comment regarding methodological determinism.
Does Popper really have an argument for indeterminism? Or just against determinism?