Suspending belief is equivalent to saying you have no belief. So be it. The b theory of time tells us nothing about (1),** because there is no “beginning” under such a theor**y.
Precisely, which is why the b-theorist has to say (1) is false.
Yes you are irrational, because the standard of proof you employ is (a) arbitrary and (b) it will keep you from truths that are more probable than not. Not that it matters in this case particularly: everything we have observed with a beginning has a cause.
First, let me clarify, I used a phrase sloppily. If you think something is more probable than not, then you’ll
believe it. But, this standard says not all of your beliefs are knowledge, which seems obvious. It places the rationality threshold higher than ‘more probable than not.’
Second, there’s no reason to accept (a). It seems self-evident that the stronger evidence we have for a position, the greater probability it is that the position is true.
With my clarification in hand, you would still
believe things which are more probable than not, but you wouldn’t take yourself to
know them simply by virtue of that.
As to your final comment, I’ll reproduce some of my thoughts from post 10:
Further, all of our experiential support confirms things which begin in time as having causes. None of it confirms things having a cause which begin to exist with time.
Since the universe is alleged to have began with time, none of our experience lends support to the universe having a cause because it began.