Today we are going to examine this article on the physics of string theory, “Philosophers Want to Know Why Physicists Believe Theories They Can’t Prove”.
As we discussed in one of our earlier articles, “Physicists vs Reality”, it starts in a rather refreshing way:
It’s often assumed that physics and philosophy are at opposite ends of the academic spectrum. In fact, they’re close—so close that they can overlap…”
Interesting, it is not that often you get to see people admitting that philosophy might be of any relevance at all to physics. Not a lot of physicists would admit this.
I suppose that it should not too be too surprising that philosophers might know better. And even less surprising that a philosopher of science might think this.
We will be hearing from one such, Richard Dawid, in this article.
Here is something he has to say:
The criteria for establishing a theory, he discovered, is not in itself subject to scientific enquiry. “They’re considered background assumptions,” says Dawid. “It’s a question that’s driven by physics but it’s a philosophical question.”
There are criteria for establishing a theory. At least there is if you want to do it rationally.
First, your theory should have a rational foundation. It should start with known facts, be it direct observational results. Or with something else we know to be true based on observation. Then we attempt to build up from there.
One should study the facts of reality and identify some implications of those facts. One should then focus in on one or more implications of reality and attempt to see what new facts one might be able to identify.
These form the basis of one’s hypothesis, some proposed fact of reality one wants to prove to be true. One then needs to validate this in some way.
In the physical sciences, this involves experimentation. One needs to perform experiments that validate that hypothesis and then show that it is indeed true.
In more abstract subjects, such as mathematics, one might need to perform a mathematical proof, based on logic. Such proof shows that given some established premise, that a given conclusion is true or false.
In any case, one needs some valid way to prove their hypothesis and show that they have indeed identified some fact of reality.
So, yes, there are criteria for establishing a theory. And the philosophy of science helps establish what these criteria are.
And guess what Mr Dawid, philosophy is a science.
To quote Ayn Rand:
Philosophy is the science that studies the fundamental aspects of the nature of existence. The task of philosophy is to provide man with a comprehensive view of life. This view serves as a base, a frame of reference, for all his actions, mental or physical, psychological or existential. This view tells him the nature of the universe with which he has to deal (metaphysics); the means by which he is to deal with it, i.e., the means of acquiring knowledge (epistemology) …Ayn Rand, “The Chickens’ Homecoming”, Return of the Primitive: The Anti-Industrial Revolution, 45
That is right, philosophy includes metaphysics, that is, our view of the fundamental view of existence. Which, ideally, one would approach scientifically.
It also includes epistemology, the science of how one goes about gaining knowledge. And this would include how we would go about performing science. Which, again, ideally, we would approach scientifically.
Despite what many philosophers might believe, philosophy is not a bunch of subjective thoughts where one argues whatever one wants.
At least, it does not have to be approached this way.
To the contrary! Ayn Rand shows that philosophy can and should be approached as a systematic study of reality, of mankind’s nature and his relationship to the world around him. It should start with observation and work its way up from that.
Observation is something that scientists themselves often implicitly dismiss. What with Kant trying to argue that we cannot trust our senses and a lot of philosophers agreeing with him.
So, it is little wonder many of them can find no basis for their philosophical ranting.
[M]any serious physicists seem to have abandoned this model. String theory, for example, is one of the most exciting ideas in modern physics. But it’s not testable—so how can physicists be confident that it’s sound?
They cannot be. Anyone can come up with any kind of theory that they like. I could come up with a system that tries to explain physics as the product of little meta-puffballs (credit to Leonard Peikoff for this amusing idea or at least one like it).
Let us suppose that it is consistent and that if the universe is made up of meta-puffballs, that this would explain everything we see in physics. Does this make the theory true? Does this make this a good theory or good physics?
No, it does not. A theory is not true simply because it is self-consistent. It is not true because it might explain how things work.
What if meta-puffballs do not exist? Or if they have no bearing to anything we can observe? What if the theory does not explain anything?
We need to test theories against the facts of reality. And not simply come up with a purely mathematical hypothesis that may or may not describe the nature of real objects.
We do not want these hypotheses to fail to describe the interactions of real entities.
There is a need to verify that our theories describe actual fundamental entities and their actions. And not a simply self-consistent mathematical theory that may not describe how reality works!
Not that string theory is internally consistent anyway.