The subject of authorship comes up frequently so he has addressed it a few times, but here is a short (under 7 minute) video. It isn't just an assertion, he gives reasons why he makes these claims:
And there’re allusions to apostolic naming in things like Justin Martyr’s first apology, Ch67 (155CE, dating largely from it being co-addressed to Marcus Aurelius):
“ the memoirs of the apostles or the writings of the prophets are read, as long as time permit”
sigh If only the department of education was as well funded as the department of war.
Estimates of criminal activity, for example, are frequently counted as GDP in places like the UK. And even if you’re working in violation of visa rules, the IRS will still expect and enforce taxes.