II.
Logical Priority.
I find some difficulty in reconciling with each other, and with the traditional rules of Formal Logic, the statements with regard to Implication through which the definition of Logical Priority is applied, in the work before us, to different cases. I think that there is at least a primâ facie obscurity which is worth pointing out. My predisposition is favourable in one sense to the new Realists. For I am inclined to think that the most obvious difficulty which I shall indicate arrives from their recognition of a point in which the traditional rules of implication are at fault, in a way to which I have frequently drawn attention. On the other hand, if I am right, the doctrine of Logical Priority would be in some degree affected.
I take into consideration three passages in the book which seem to me to agree; and also two passages, continuous with the first and third of the three, which seem to me to introduce a different point of view, inconsistent with that of the former passages and with itself, though, I am convinced, containing an important truth.
The three passages first mentioned are (a) p. 45, from the words "First, one science," to p. 46, ending with the words "required quantity of arsenic"; (b) p. 112, "It is important" down to "the premises be false"; and (c) pp. 204-5,
