But in our present state of knowledge, any reasoning on this supposition would probably appear too fanciful.

Some day we may find out how much ancestral experience is capable of bequeathing in this way, whether simply shadowy, undefinable mental tendencies, or something like definite concrete ideas.

If, for example, it were found that a child that was descended from a line of seafaring ancestors, and that had never itself seen or heard of the "dark-gleaming sea," manifested a feeling of recognition when first beholding it, we might be pretty sure that such a thing as recollection of prenatal events does take place.
But till we have such facts, it seems better to refer the "shadowy recollections" to sources which fall within the individual's own experience.
We may now pass to those hallucinations of memory which are analogous to the _centrally_ excited hallucinations of sense-perception.

As I have observed, these are necessarily vague and imperfectly developed.
I have already had occasion to touch on the fact of the vast amount of our forgotten experience.

And I observed that forgetfulness was a common negative condition of mnemonic illusion.