Nor does there seem to be any simple way by mere reflection on the contents of our memory of distinguishing what kinds of recollection are likely to be illusory.
How, then, it may be asked, can we ever be certain that we are faithfully recalling the actual events of the past?
Given a fairly good, that is, a cultivated memory, it may be said that in the case of very recent events a man may feel certain that, when the conditions of careful attention at the time to what really happened were present, a distinct recollection is substantially correct.

Also it is obvious that with respect to all repeated experiences our memories afford practically safe guides.

When memory becomes the basis of some item of generalized knowledge, as, for example, of the truth that the pain of indigestion has followed a too copious indulgence in rich food, there is little room for an error of memory properly so called.

On the other hand, when an event is not repeated in our experience, but forms a unique link in our personal history, the chances of error increase with the distance of the event; and here the best of us will do well to have resort to a process of verification or, if necessary, of correction.
In order thus to verify the utterances of memory, we must look beyond our own internal mental states to some external facts.

Thus, the recollections of our early life may often be tested by letters written by ourselves or our friends at the time, by diaries, and so on.