He's saying that just because you don't have first-hand experience with something, or can't fathom how something is possible, doesn't mean it can't happen.
Thank you ssharp, that's exactly what I was trying to convey.
Huh. I read your comment more as "you can be perceived as an expert in your trade and still suck at it." Groping a potential client's boobs is a clear sign of sucking at being a VC.