Dear Ian
thank you for your compliments and your interesting comments. You reminded to me to buy the Eddington book on Amazon about the physical law, which can be a great source of inspiration for me. I know from our last discussion (in Boston, am I correct)? that you are not a structuralist. I didn't know that Steven French was your external advisor. How can it be that then you don't completely agree with me?
Let me answer to your two pints, very briefly.
The power of mathematics in physics is mostly resides in the mathematical induction (not in the physical one, which is logically fallacious, as Hume first noticed). With the mathematical induction, with a couple of modus ponens you prove an infinite large set of true assertions. But as you know, you do not prove the assertion for n=infty! Working with infinity is for mathematical convenience only, for describing analytically asymptotics. If you avoid the "actual infinity" but you work only with the "potential infinity" how can you get an unprovable assertion from 1+1=2, 1+2=3, 1+3=4, ...? Moreover, a theory should be required to be computable, namely allowing a finite-state machine one must be able to describe a finite portion of reality. Clearly you can incur into incompleteness if you want describe the whole universe. But not for a finite portion of reality, as long as you keep it discrete! Again, continuum is a limiting case of discrete ...
Second point: About causality, you forget that in my work with Chiribella and Perinotti on the axiomatic derivation of quantum theory we have a precise mathematical definition of causality, which has exactly the physical interpretation that a physicist would agree with.
Finally: there are bias that are universally shared. For example: we believe in logic, we believe in the universal validity of a law (or we treated it as such), we believe in isotropy of the low, we believe in locality of interaction. If you don't share one of this biases (which are examples of the principles from which we derive also free QFT), then I would be very interested in knowing which one you don't share. Don't tell me that the law is not universal, as Lee Smolin says, otherwise you are required to provide a higher level law accounting for the variation of the low-level law--otherwise you are giving up the theory. For how long would be a law required to be valid in order to be a law? A century? a second?
And, finally: I don't care about objective reality. What I care is that the theory is describing objective experimental data. My daughter still believes that Santa Claus is an objective reality, but the only objective facts are the presents that she gets.
Thank you again very much for your compliments and stimulating comments.
I will look forward to meeting you soon again. I'll be in Chicago the full August. If you'll pass by, please let me know.
My very best regards
Mauro