A word may be said about the attempts which philosophers have made to extricate themselves from the difficulty without giving up Causality as an ultimate principle of explanation. The least philosophical method of escape is that of arbitrarily postulating a first cause with no preceding cause, which amounts to the same thing as a beginning of existence or a first moment of time. This way out of the difficulty obviously amounts to an arbitrary desertion of the causal principle at the point where it becomes inconvenient to remain faithful to it. Whatever the nature of the event you pitch upon as your “first cause,” the causal principle, if logically valid at all, is just as applicable here as anywhere else Your “first cause” must have had a previous cause, or else the whole causal scheme must be, as we have contended that it is, the illogical and imperfect perversion of a genuine principle of systematic connection, useful and indeed indispensable in practice, but quite indefensible in theory. It would not help you out of the difficulty to distinguish between a first event and a first moment of time, by postulating a first cause with an indefinite lapse of empty time before it. For the causal principle would then require you to look for the determining conditions of the first event in the preceding lapse of empty time. But this lapse, because merely empty, cannot contain the determining conditions for any special occurrence in preference to others. This is why the conception of a beginning of the causal series in time, with an empty lapse before it, has always led to the insoluble riddle, “Why did God create the world when He did, rather than at some other point of time?”