For all philosophies, whether they be Bergson’s or the view of common sense or any other, the actual facts which require to be explained are the same, and, though any positive assertion as to what these facts are may be hotly disputed, it will probably be admitted that as we ordinarily know them they consist in some direct experience, undeniable as far as it goes. The point at issue between Bergson and common sense is, precisely, how far it does go. Both sides would admit that, in this fact directly known, what is in the full focus of attention at any given moment is very limited; on the other hand both would admit that this fully focussed fact is set in a context, or fringe, with no clearly defined limits which also goes to make up the whole fact directly known though we do not usually pay much attention to it. The fact directly known being given the problem is to find out 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.