With admirable clarity, astronomer and physicist Marcelo Gleiser explains what a Theory of Everything is and is not: It’s not about every detail of life that happens to us.

It’s the search for a single, underlying force that unites the four fundamental forces of nature — gravity, electromagnetism, the strong nuclear force, and the weak nuclear force — into one single underlying force. Why haven’t we found it? Well, first, he says, “We do not see this unity because it is only manifest at extremely high energies, well beyond what we can perceive even with our most powerful machines.”

But second — and more significantly — there is a real question, Gleiser contends, whether science is by nature suited to finding such a force:

As the physicist Werner Heisenberg, of Uncertainty Principle fame, once wrote, “What we observe is not Nature itself but Nature exposed to our methods of questioning.” What we can say about Nature depends on how we measure it, with the precision and reach of our instruments dictating how “far” we can see. Therefore, no theory that attempts to unify current knowledge can seriously be considered a “final” theory or a TOE, given that we cannot ever be sure that we aren’t missing a huge piece of evidence.

Marcelo Gleiser, “A “Theory of Everything” doesn’t make sense” at Big Think (December 1, 2021)

That makes a lot of sense if we think about it. A Final Theory developed by science-minded people in ancient civilizations would not have included what we can learn from the microscope, the telescope, magnetic resonance imaging… We are all at the mercy of what we can’t know. As Gleiser puts it,

How are we to know that there isn’t a fifth or sixth force lurking out there in the depths? We cannot know, and quite often, hints of a “new force” are announced in the media. To put it differently, our perennially myopic view of nature precludes any theory from being complete. Nature doesn’t care how compelling we think our ideas are.

Marcelo Gleiser, “A “Theory of Everything” doesn’t make sense” at Big Think (December 1, 2021)

Generally speaking, the more we know, the more we find out we don’t know. We fill in blanks and then more blanks appear beside them. One of the blanks, instead of just being filled in, may lead to a whole new discovery.

As Gleiser puts it, “The very process of discovery leads to more unknowns.” And they may be smaller or larger.

For example, in 1977, Carl Woese (1928–2012) almost accidentally discovered a huge and significant Third Kingdom of life, the Archaea — which are neither bacteria nor more complex life forms (eukaryotes).

The fifth and sixth forces may be out there too.

Science is not, at any time in the foreseeable future, going to be all tied down and delivered in a box.

You may also wish to read: Can quantum physics, neuroscience merge as quantum consciousness? Physicist Marcelo Gleiser looks at the pros and cons of current theories. The problem is, if we assume that “the mind is nothing more than the brain,” there may be nothing we can discover about how it works.

and

Does science disprove free will? A physicist says no. Michael Egnor: Marcelo Gleiser notes that the mind is not a solar system with strict deterministic laws. Apart from simple laws governing neurons, we have no clue what laws the mind follows, though it does show complex nonlinear dynamics.

Also: Astronomer: We can’t just assume countless Earths out there. He points out that the Principle of Mediocrity is based on faulty logical reasoning. Marcelo Gleiser notes that the starting point of the Mediocrity Principle assumes countless Earths. That’s not a conclusion from evidence. It’s bad logic.