The fact that an atheist can be 'clearly aware that the three angles
of a triangle are equal to two right angles' is something I do not
dispute. But I maintain that this awareness of his is not true knowledge,
since no act of awareness that can be rendered doubtful seems fit to be
called knowledge. Now since we are supposing that this individual is
an atheist, he cannot be certain that he is not being deceived on matters
which seem to him to be very evident (as I fully explained). And
although this doubt may not occur to him, it can still crop up if someone
else raises the point or if he looks into the matter himself. So he will
never be free of this doubt until he acknowledges that God exists.
(Second Replies)