As a matter of fact, we have seen, when studying the illusions of memory, that our personal experience does become confused with that of others.

And one may say that all long-cherished retrospective beliefs tend to become assimilated to recollections.
Here then, again, there seems to be room for illusion to arise.

Even in the case of a recent past event, directly made known by present objective signs, the mind is liable to err just as in the case of forecasting an immediately approaching event.

And such error has all the force of an illusion: its contradiction is almost as great a shock as that of a recollection.

When, for example, I enter my house, and see a friend's card lying on the table, I so vividly represent to myself the recent call of my friend, that when I learn the card is an old one which has accidentally been put on the table, I experience a sense of disillusion very similar to that which attends a contradicted perception.