But peer review works completely differently in math & physics than in psychology. In math and (theoretical) physics, practically all results (claims) can in principle be reproduced (tested) by other people. Sure reviewers are usually short on time and won't verify every single detail but at the same time – being experts in their fields – they tend to be extremely good at distinguishing the "easy" arguments from more intricate ones and can usually come up with rough arguments as to why (or why not) a given new result makes sense in light of existing results & literature.