Unfortunately I missed most of his panels and interviews because I was out most of Saturday at my Kairos induction. I saw him in a panel on the story function of 'monsters' (cf Doctor Who and Lovecraft) as opposed to aliens (cf most literary SF and Trek): interestingly he argued that monsters are not less sophisticated than aliens as a plot device, although they are characterised as having a less well developed independent existence or rationale for their behaviour. This is because what they lose in intellectual development, they gain as psychological metaphor.
I commented from the floor that I thought that a monster must be both fully intentional like humans, but utterly non-negotiable like natural disasters. And that it was interesting to think why we had evolved a fear of such a creature, when none exist.
Cornell argued that there were two sources for the fear: now-extinct primate rivals to our species, and our own unsocialised offspring. I think the first is possible, interesting, and the second frankly wrong. Monsters are not toddler-analogues. FWIW I think Monsters represent our fear of our own (and hence others') capacity to violate all instinct, and devour each other. A bit like the fear of throwing ourselves off a high place - we wouldn't do it but we can envisage it.