That is equivalent to saying you can’t understand how mathematics could be a construct; or how mathematical anti-realism could possibly be true.
I assign a respectable probability to anti-realism, and hold no disrespect for anyone who is an anti-realist, but I don’t understand how anti-realism can be true. I’ve never heard a plausible model for why one thing should exist but not another. Tegmarkism sweeps away that problem, leaving the new problem of how to measure probability (why do we have the subjective experience of probability that we do when there are so many versions of myself?). I don’t have a satisfactory answer for that question, but it feels like a real question, with meat to get at, whereas in an anti-realist universe the question of why some things exist and other don’t seems completely hopeless.
Sufficiently scary, yes.
I assign a respectable probability to anti-realism, and hold no disrespect for anyone who is an anti-realist, but I don’t understand how anti-realism can be true. I’ve never heard a plausible model for why one thing should exist but not another. Tegmarkism sweeps away that problem, leaving the new problem of how to measure probability (why do we have the subjective experience of probability that we do when there are so many versions of myself?). I don’t have a satisfactory answer for that question, but it feels like a real question, with meat to get at, whereas in an anti-realist universe the question of why some things exist and other don’t seems completely hopeless.