The other YouTube popularization that regularly irks me is when people beam about how "there are lots of different sized infinities", without explaining that wh

The other YouTube popularization that regularly irks me is when people beam about how "there are lots of different sized infinities", without explaining that when mathematicians use the word "size" and "infinity" in that context, it means cardinality (technical term) of an infinite set, within an explicitly defined set theory that includes the axiom of infinity (all technical concepts).