[textninja]

He added a lesser option, catastrophically harming humanity, so whatever he meant by the first is immaterial (“there’s a 70% chance of a hurricane or strong winds”). Furthermore, if it wasn’t a high number chosen for dramatic effect the estimated percentage would be completely arbitrary.

[hollerith]

I disagree that 70% was chosen for dramatic effect.

[textninja]

No, you’re right, it was chosen because “trust me bro”.

Look, it may well be something he believes, and he’s free to prognosticate (or market) however he likes, but I see absolutely nothing to support the number outside of his own opinion.

Besides, there’s no time limit on p(doom), so it’s completely unfalsifiable (“on a long enough timescale…”), and it’s about the destruction of humanity which means it’s unprovable as well. That, in my view, makes his 70% guess a sensational statement lacking scientific merit.