Stephen Hawking: Logical Positivist

Stephen Hawking: Logical Positivist

Reading Stephen Hawking’s The Universe in a Nutshell (2001), I came upon the following passage: “Any sound scientific theory, whether of time or of any other concept, should in my opinion be based on the most workable philosophy of science: the positivist approach put forward by Karl Popper and others. According to this way of thinking, a scientific theory is a mathematical model that describes and codifies the observations we make… If one takes the positivist position, as I do, one cannot say what time actually is. All one can do is describe what has been found to be a very good mathematical model for time and say what predictions it makes” (31). Later we read: “But as a positivist, the question ‘Do extra dimensions really exist?’ has no meaning” (54). Then: “From the point of view of positivist philosophy, however, one cannot determine what is real. All one can do is find which mathematical models describe the universe we live in.” (59) More: “From a positivist viewpoint, one is free to use whatever picture is most useful for the problem in question” (118). Additionally: “The mathematical model of black holes as made of p-brains gives results similar to the virtual-particle pair picture described earlier. Thus from a positivist viewpoint, it is an equally good model, at least for certain classes of black hole” (127). Finally: “However, from a positivist viewpoint, one cannot ask: which is reality, brane or bubble? They are both mathematical models that describe the observations” (198). In his glossary Hawking defines positivism as follows: “The idea that a scientific theory is a mathematical model that describes and codifies the observations we make” (206).

What should we say about these pronouncements, none of which is defended in the book? One would not think that positivism has been a dead letter in philosophy for many decades, for well-known reasons (which I will not rehearse). Alarm bells are sounded in the first quotation when Hawking identifies Popper as a positivist: he was explicitly and vociferously not a positivist. The idea that Hawking is taken with is that scientific theories don’t describe reality or purport to say what is true but rather provide “mathematical models” (whatever they are—we are not told) that can be “useful” in making “predictions”. They don’t tell as what things are or how they work but merely provide “good” models (“pictures”); the former type of question “has no meaning”. A scientific theory merely sums up (“describes and codifies”) the observations; it does not attempt to arrive at the truth about what these observations are observations of. This is good old-fashioned instrumentalism, a descendant of classical empiricism. So, the heliocentric theory of the solar system is not true or accurate—a correct description of real things—but merely a useful device for predicting the movements of the planets (themselves just ways of summing up our observations). Darwin’s theory of evolution is not a true account of how actual species came to exist but just a “mathematical model” of our biological observations. Anything else is literally meaningless. I won’t go into the very familiar arguments against such ideas; what is remarkable is the way Hawking adopts an extreme positivism without even acknowledging that he is saying something highly controversial (I would say complete rubbish). He is a physicist attempting to talk philosophy and making a complete hash of it. He obviously has no idea what he is talking about, but that is no impediment to making confident philosophical pronouncements. Has he ever read any positivist literature (e.g., Ayer’s Language, Truth and Logic) or had a look at Popper’s writings? I doubt it. Instead, we are told what his “opinion” is, as if he has a right to say whatever he likes when it comes to philosophy, which is just a bunch of “opinions” anyway.

But there is a deeper and more disturbing point to be made: at least Hawking knows he is a positivist—he is aware that he taking a philosophical stance in his physics. I don’t know how many times I have read a physicist (Einstein is a prime example) and thought, “He is clearly making positivist assumptions but is quite oblivious to the fact”. They think they are just talking plain common sense with which no one could sanely disagree. Obviously, this kind of attitude is deeply embedded in the culture of physics as it is now practiced. It is simple verificationism: what is real is what is verifiable. Any questions that don’t yield to verification must be deemed meaningless. Reality reduces to what is humanly knowable by means of the senses. That is just terrible epistemology. Yet it is tacitly taken for granted by supposedly educated people. So, I am grateful to Stephen Hawking for laying his cards on the table, shocking is it may be to see what those cards reveal.[1]

[1] From the point of view of human vices, it is the sheer overconfidence of many physicists that really shocks me.

2 replies
  1. Free Logic
    Free Logic says:

    Hawking was an unapologetic snob towards philosophy as is well known. He was much more of a snob than he understood any philosophical matter as you illustrate here. This condescending attitude is quite wide spread in physics, chemistry and in so called hard sciences and also in engineering disciplines. Thankfully though, there are exceptions (Deutsch, D’Espagnat, Bohm are just a few) and much more so among the mathematicians just as one would expect.


Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.