what it is and how it comes to be known. What is actually given and
needs to be accounted for is the fact clearly focussed, with its less
clearly defined fringe: Bergson's sweeping assumption of the existence
of a further vast field of virtual knowledge in order to account for
it, does, at first sight, seem arbitrary and unwarranted and in. need
of considerable justification before it can be accepted. For him the
problem then becomes, not to account for our knowing as much as we do,
but to see why it is that we do not know a great deal more: why our
actual knowledge does not cover the whole field of our virtual
knowledge. Common sense, on, the other hand, sets out from the
assumption of ignorance, absence of awareness, as being, as it were,
natural and not needing any accounting for, and so it regards the
problem as being to explain why any experience ever occurs at all. The
assumption of ignorance as being the natural thing seems at first
sight to need no justification, but this may well be due merely to our
having grown accustomed to the common sense point of view. When one
begins to question this assumption it begins to appear just as
arbitrary as the contrary standpoint adopted by Bergson. The actual
facts are neither ignorance nor full knowledge and in accounting for
them it is really just as arbitrary to assume one of these two
extremes as the other. The truth appears to be that in order to
account for the facts one must make some assumptions, and these, not
being facts actually given, are bound to be more or less arbitrary.
They seem more or less "natural" according as we are more or less
accustomed to the idea of them, but they are really justified only
according to the success with which they account for the actual facts.

This idea of putting the problem of knowledge in terms exactly the
reverse of those in which it seems "natural" to put it was originally
suggested to Bergson by his study of the important work on amnesia