Stephen Hawking’s Defense of Positivism

In my last post I finished comparing Popper and Kuhn and again concluded that there really isn’t much difference between the two other than on the issue of Scientific Realism vs. Positivism. That is to say, Popper believes that science actually discovers theories closer and closer to the truth whereas Kuhn believes it becomes more useful over time in ways that we humans wish it to be, but that there is not necessarily some underlying truth to be discovered.

In a previous post I previously considered the advantages of Scientific Realism vs. Positivism. (See also here) Both have pros and cons, but Scientific Realism is the clear winner when it comes to generating new conjectures and theories. If one were to solely believe in Positivism one would never actually believe in their own theories enough to think up new questions/problems to solve and test. The end result would be the stagnation of science.

However, this fact aside, does this mean Scientific Realism is actually true and Positivism false?

Hawking’s Defense of a Positivist View of Reality

Recently Hawking wrote a book called The Grand Design. In that book, Hawking makes a number of controversial assertions. The one that got the most press time – don’t you just love the media? – was the claim that the laws of physics are sufficient to create the universe and that God has no role to play. This is, actually, a very interesting point and one that deserves rigorous criticism – which I’ll gladly give it in the future.

But in reality, this wasn’t the most important challenge that Hawking makes. The really big challenge Hawking makes in his book is that Positivism is actually the nature of reality, not Scientific Realism. We saw in this past post that Hawking is a Positivist.

I perceive much in common between Hawking’s and Kuhn’s views. But whereas Kuhn’s concern was from the point of view of a historian – he merely wanted to know how we progress in science – Hawking is an eminent scientist and actually argues that there is no underlying reality for science to find.

In an article in Scientific American (October 2010) Hawking summarizes the arguments he makes in his book. If Hawking is correct, it will have serious consequences for Scientific Realism and for our desires to find a “Theory of Everything.”

Most people believe that there is an objective reality out there and that our senses and our science directly convey information about the material world. Classical science is based on the belief that an external world exists whose properties are definitive and independent of the observer who perceives them. In philosophy, that belief is called realism.

Those who remember Timothy Leary and the 1960s, however, know of another possibility: one’s concept of reality can depend on the mind of the perceiver. That viewpoint, with various subtle differences, goes by names such as antirealism, instrumentalism or idealism. According to those doctrines, the world we know is constructed by the human mind employing sensory data as its raw material and is shaped by the interpretive structure of our brains. …

The way physics has been going, realism is becoming difficult to defend. (p. 70)

And what does Hawking suggest instead?

Instead we adopt a view that we call model-dependent realism: the idea that a physical theory or world picture is a model (generally of a mathematical nature) and a set of rules that connect the elements of the model to observations. According to model-dependent realism, it is pointless to ask whether a model is real, only where it agrees with observation. (p. 70)

Possible Ramifications To Positivist Universe

If there is only a model-dependent realism to be found, what does that mean for science? For one thing, Hawking argues, we should not expect to find a single “theory of everything.” “It now appears that this quest may yield [in string theory] not a single theory but a family of interconnected theories, each describing its own version of reality…” (p. 70)

Would this really be so bad to find that Kuhn was right after all and that scientific progress does not grow closer to some all encompassing view of reality? [1]

Notes

[1] I confess, I don’t even come close to understanding string theory and it’s ‘family of theories’ well enough to comment on this much. From what I understand, this is a matter of ‘string math’. There were five different mathematical ways to express strings that each turned out to be equivalent to each other. However, each way had certain advantages and disadvantages. The best part about this is that one can flip to the version that is easiest at the moment. Plus, each one eliminates certain kinds of error factors. I can see why this would appeal to a positivist like Hawking. But I’m not sure this really undermines the scientific realist world view either, again showing that both view can be useful, but not necessarily at the same time.

For example, a more recent proposal is that quantum field theory and string theory are one and the same, except that string theory is the 11 dimensional holographic projection of 4 dimensional quantum field theory. (See Brian Greene’s The Hidden Reality). In this view, there is still an underlying reality, it’s just that it can be mathematically viewed from more than one point of view.

To a lesser degree, I’ve noticed this in many aspects of life. We often express the same thing in different ways, often in seemingly opposite ways. For example, I’m convinced that the ‘orthodox’ Christian concept of creation ex nihilo and the Mormon concept of creation from ‘pre-existing matter’ will eventually be forced by the laws of physics into being one and the same concept with each being merely different ways of wording the same thing. But this only turns out to be true if we accept the lawful nature of reality. In other words, both points of view can only both turn out to be true if both accept that they were only approximate concepts of a very more specific set of laws and therefore they weren’t actually mutually exclusive to begin with.

16 thoughts on “Stephen Hawking’s Defense of Positivism

  1. 2 quick points, since I’m short on time.

    1) I find myself going crosseyed with your definition of positivism since the logical positivists were the kings of realism.

    2) if one applies the realism/positivism labels to religion, I think the important differences between the two become a bit more urgent.

  2. A scientist who doesn’t believe in reality is a scientist who doesn’t believe in truth. And a scientist who doesn’t believe in truth (or facts for that matter) must confess that he doesn’t really know anything at all, not even the state of his own mind.

    The whole idea that there is no reality, and hence no facts, is absurd, especially for a scientist. What possibly could make a scientific theory more or less “useful” except an external reality to measure that against?

  3. There are certainly those, like David Hume, who can make a plausible argument for the non-existence of physical laws (it is all co-incidence you see, and there is no way of constructing a deductive proof to the contrary), but for a scientist the idea that the world isn’t real is preposterous.

    Philosopher David Stove wrote a lot about this subject:

    The Kuhnian is scandalized if you call a current scientific paradigm `true’ or an earlier one `false,’ or if you say that the later one is `probably nearer the truth’ than the earlier. Paradigms are incommensurable, he tells you, and no special authority attaches to one which governs a field of science now. And why must we accept this astounding and sordid democracy of paradigms? Why, just because, in any field, even the best scientific knowledge which is current now, or at any time, is always rigidly constrained within the limits imposed, by the paradigm prevailing at the time, on scientific knowledge

    The idea that scientific theories are incommensurable is the sort of statement that only someone truly ignorant or truly insane could make. Just about the only reason why we ever move from one scientific theory to another one is if both are commensurable and the latter is empirically demonstrated to be be in better accord with the facts, and in the case of a truly respectable theory, to have an overwhelming level of predictive power as well.

    What business does one have being a scientist if he doesn’t believe in facts? Or physical laws for that matter? Kuhn of course was no scientist, but he should have known better.

  4. The blockquote markup appears to be being ignored. The Stove quote ends with “by the paradigm prevailing at the time, on scientific knowledge”.

  5. I’m having some trouble with the site as well. When I use my iPhone, the entire right half of the comments is blacked out.

    As for Kuhn, I agree that any strong sense of the term ‘incommensurability’ is in fact nonsense. Even still, I see where these theory independent ‘facts’ against which theories are supposedly measured is supposed to come from. Of course some theories work better than others, but this isn’t really news to the non-realists, some of which have been very accomplished scientists.

  6. Jeff says: “the logical positivists were the kings of realism”

    Well, they certainly thought of theselves like that, yes.

    Are you familiar with Popper’s views on how that isn’t the case?

  7. Hmmmm… Aside from his general argument for the falsificationist criterion I’m not sure.

    But then, I’m not really sure that popper is relevant. The point is that some of the most brilliant minds were both positivists and realists at the same time. Thus, to equate positivism with non-realism seems strange.

  8. “some of the most brilliant minds were both positivists and realists at the same time”

    No, they thought they were. But upon further inspection, Positivism isn’t the same as Realism.

    The Positivists insisted that Popper was Positivist. And Popper insisted he was not. I think we’ve had enough time to look into this now to konw Popper was not a Positivist. It was the Positivists that had misunderstood.

  9. Jeff,

    I’d like to get past the issue of authority (Popper says vs. the Positivist said.)

    This is actually simple. Define positivism such that it’s different from Hawking’s definition (i.e. he considers himself a positivist.)

    If you can, then we are using a single label to mean two things and are thus talking past each other. Easy.

    If you can’t, then Positivism isn’t Realism because they mean two different things. (Or at least they are not as per our current definitions.) Still easy.

    The only difficulty will come if you decide that “owning the word” matters. In which case, I’ll just let you own the word and you can assume I mean “Hawkings-Positivism or Model Dependent Reality” instead of whatever you mean by “Positivism.”

  10. On the other hand, I think you should seriously consider the possiblity that the famous positivists weren’t as much realists as they thought they were. There is nothing inconsistent about this posibility. Being brilliant is no bar to making a very logical philosophical mistake.

  11. Hmmm….

    First of all, I agree with you regarding the futility of arguing about definitions.

    As I understand the logical positivists (in their construal of the early Wittgenstein anyways) they thought that once we cash out our ordinary language in terms of a “pure” logical language – a language which they thought necessarily carved nature at its joints – then true statements would literally describe reality as it actually is.

    Of course, logical positivism is clearly self-refuting, but it does seem like a doctrine which could have been both positivist and realist.

  12. My understanding is that positivism is first and foremost an epistemological position about what can count as knowledge. But then it seems to bifurcate between a realist camp and an anti-realist or instrumentalist camp. If you start with the proposition that a statement about the unknowable is meaningless it is easy to see why some would tend to the latter position.

    Hawking’s statements quoted above, however, are sufficiently vague that it is difficult to tell which side of the divide he is on. He presents three alternatives which do not contradict each other. First is classical realism, the second is a statement about epistemology, and the third is about the strict unreality of models.

    It is difficult to tell exactly what he means by “model-dependent realism”, because that is a clear oxymoron, but he does seem to agree that some models are better than others, which can only be the case if the world is real.

  13. Mark D says: “Hawking’s statements quoted above, however, are sufficiently vague that it is difficult to tell which side of the divide he is on”

    You know, I agree!

    Keep in mind that this posts are reprints (Mark D knows this since he read the originals.) So to some degree I’ve changed my thoughts by now.

    So I can say that as of today I think Hawking’s statements are a bit on the vague side.

  14. Jeff G,

    I am not a fan of Wittgenstein in the slightest. But from what little I know, I think you pretty much described him correctly.

    Is Positivism a type of realism in some instances? (As Mark D suggests.)

    I think we then have to answer “what do we mean by realism?” Clearly vWittgenstein thought he was being a realist — or rather at first he believed that. From what I understand, he changed his mind at the end of his life. (MarkD or Jeff G, can you confirm or deny that? Not my area of interest.)

    But I think the Popperian view of Realism is mutually exclusive from the Wittgenstein view of Realism. So that means “Realism” might be too vague a statement by itself.

    So I guess, for these posts, you’ll have to contextually pick up what *I* mean by “Realism” based on how I describe it. (I’m really following David Deutsch’s views in many places where I quote him. And Deustch is a Popperian.) I think I describe it well enough for the purpose in the posts.

  15. That’s right about Wittgenstein. His first work – The Tractatus – was pretty much the founding document of Logical Positivism. His second work – Philosophical Investigations – was pretty much the work which ended Logical Positivism and initiated Ordinary Language philosophy. That is where his ideas of language games, the public nature of rules and family resemblance come from. The latter Wittgenstein would probably see the entire realism debate as a case of us taking ordinary terms (real, true, etc) out of their ordinary contexts and forcing them to perform tasks they were never meant to perform.

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