Stephen Hawking’s Defense of Positivism

This is a historical post

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 posts I previously considered the advantages of Scientific Realism vs. Positivism. 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.

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 posts 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 views 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.

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