I would contest that the approach is rational, or that it avoids the epistemological issues. I would argue that it is, at best, 'a'rational. A little thought will suffice to show that we can come up with a much larger number of irrational things, than rational things, to believe. Many of these might be comforting to us.
I enjoy Gardner's books very much, but I cannot respect this justification for belief in God. He is simply wrong.
Personally, I don't regard Gardner's justification as
sufficient either, but it is certainly a
necessary one, given the wide array of logical, empirical and epistemological objections to the existence of god. However, I think that one must acknowledge Gardner's more-than-adequate expertise in scientific, logical and philosophical matters, so it would be fairly safe to assume that his justification actually comprises a great many more tentacles, and that we are faced only with the essence of it (c.f. Descartes'
cogito, ergo sum). Also, Gardner makes no attempt to assert the actuality of god's existence itself (and thereby he avoids ending up in all sorts of hot water); he merely provides a utilitarian reason for why he himself holds such a belief.
The question of taking comfort from believing that you might imminently receive a suitcase full of cash is not a good analogy. The existence of such suitcases and cash is hardly in question, and, though unlikely, it is not impossible that your belief might find actual validation. In contrast, god's existence is not established.
The point is that if, for example, you choose to believe that lime-green, vanilla-flavoured unicorns with pink hooves exist, then the most acceptable defence for your belief, absent any empirical or logical evidence for it, is that it affords you some practical and/or personal advantage. With this in mind, it would be presumptuous to deny that Gardner derives the comfort he claims to. Also, it is necessary to distinguish between a belief itself and the consequences it may provoke. There is nothing in principle wrong with
holdingthe aforementioned belief in unicorns; however, if that belief includes the idea that household pets are preventing the unicorns from achieving their purpose and this prompts you to embark on a large-scale cat and dog extermination campaign, then that becomes a rather different matter.
'Luthon64