Perhaps too much is being made of the "arbitrarily close to zero" remark. Sure, there isn't enough information in the universe to get to one-over-number-made-with-up-arrow-notation. But there's certainly enough to get to, say, one in a thousand, or one in a million; and while this isn't arbitrarily close to zero in a mathematical sense, it's good enough for merely human purposes. And what's worse, the word 'arbitrary' is distracting from the actual argument being made, in what looks to me like a rather classic case of "Is that your real objection?"