First, Deutsch is a serious field theorist and foundational quantum mechanist. Second, the arXiv is not, as you seem to intimate, for work that isn't good enou

First, Deutsch is a serious field theorist and foundational quantum mechanist. Second, the arXiv is not, as you seem to intimate, for work that isn't good enough to pass peer review, but is, instead, a place to post work so that the physics community can digest it without a 6-month peer-review delay. Articles on the arXiv are almost always submitted to a journal within a few days of being posted. I should point out: that doesn't mean it's right! But it's not gobbledegook either.