3 ms·
The secret that is rarely revealed in pop science discussions is that theories of everything are cheap. To count as a theory of everything, you just need to com
by knzhou 7y ago
The secret that is rarely revealed in pop science discussions is that theories of everything are cheap. To count as a theory of everything, you just need to come up with any mathematical structure big enough to cram the Standard Model plus a graviton in. And adding mathematical structure, especially when you're playing around, is easy, like snapping legos together. In this way, you can crank out ten theories of everything a week if you want to.
So how do we decide what is worth actually taking seriously? First, you need to establish that your theory actually reproduces the Standard Model plus gravity at low energies, i.e. that it doesn't blatantly fail to match the something we already know. (Most ideas fail here.) Then, you need to show that your proposal is actually mathematically self-consistent. (Most remaining ideas fail here.) Then, you need to work on the finer details, i.e. making sure you don't accidentally predict large deviations from the Standard Model that contradict observation, and match what we know about quantum gravity already at the semiclassical level. (Everything except for string theory fails by this point.) And then finally, you need to be able to extract sharp predictions from your theory -- and this is quite hard, because a complicated theory tends to have a lot of knobs to twiddle, making the predictions ambiguous. (Nobody has gotten this far.) And even if you pass all of these checks, there's a high chance the predictions will be wrong anyway, because nature's not our slave.
Weinstein's theory has not even gotten past step zero. He hasn't provided enough technical detail to calculate anything, there's just nothing there at all. Yet he made a huge media push to get recognized as "the next Einstein". It's like saying your startup is the next Google before writing a single line of code, and having the public believe you.
- Igelau 7y agoYou have a couple threads going in here, so maybe you tacked this to the wrong one. You said you could speak for sure about things he'd said about physics, so I'm asking for those specifics.
- knzhou 7y agoThese are the specifics. There isn't enough there there in his theory to have anything more to criticize. That is, it's too vague to even do the zeroth-order tests physicists would use to decide whether to take it seriously. (You could criticize the little there is on aesthetic or philosophical grounds. I tried to avoid this because that's subjective, but it is true that there is a great deal more arbitrariness in his construction than in alternatives. For example, string theory also has a lot of extra dimensions, but the number of them is fixed by internal consistency. It wasn't just made up.)