T H E activities with which I shall be concerned in this essay are familiar enough to writers and readers of history, though relatively little attention has been paid to them by those who have worked on the theory of the subject. To introduce them I shall mention only that, when we are confronted with a set of historical facts, one of our first tasks as students of history is to discover what they add up to, a result we achieve by identifying the continuing processes to which they belong or bear witness. I want to ask what assumptions are involved in thinking of this sort, and whether it requires any special type of concept. I admit that my initial description of the situation to be examined is vague; my hope is that it will be replaced by something more precise as the discussion proceeds. At the outset I can say little more than that I have questions to raise about the common historical activity of saying what was going on at a particu­ lar time in the past.