^{page 445 note 1} New Background of Science, p. 19.

^{page 447 note 1} “Nous sommes dans une classe de 4^me, le professeur dicte; le cercle est le lieu des points du plan qui sont à la même distance d'un point intérieur appelé centre. Le bon éléve écrit cette phrase sur son cahier; le mauvais éléve y dessine des bonshommes; mais ni I'un ni l'autre n'ont compris; alors le professeur prend la craie et trace un cercle sur le tableau. ‘Ah!’ pensent les éléves, ‘que ne disait-il toute de suite: un cercle est un rond, nous aurions compris’ ” (Poincaré, , Science et Méthode, p. 129Google Scholar).

^{page 447 note 2} In this paper I am using the words “infer” and “inference” in a somewhat different manner from that now usual. “Inference” is now generally confined to conscious processes, and for this usage there is much justification, as it emphasizes certain important distinctions. On the other hand, it conceals certain distinctions which are important for my purpose. The assertion “this leaf is green” is no more the result of conscious inference than “I am seeing green,” but there is an important difference between them; the latter can, with a little explanation, be made to satisfy the Cartesian test of certainty, but the former never can. That it may be valid it is necessary that there should be, if not an actual, yet a possible inference. Between the data and the conclusion can be inserted, at least theoretically, a number of steps, and the result will be an inference in the strictest sense; moreover, if these steps could not be inserted, or the inference were incorrect, the assertion would be false, or at best only accidentally right, right as an answer drawn from a lucky bag might be. I shall usually say that such assertions or conclusions are of the nature of inference or contain an element of inference, but as these phrases are rather lengthy I may occasionally have to use the word “inference” by itself. It is a defect in philosophical language that it contains no word to express the distinction I mean, but I know of none.

^{page 450 note 1} See New Oxford Dictionary.

^{page 453 note 1} Modern Introduction to Logic, p. 423.

^{page 453 note 2} I imagine that Sir James would admit this, but say that his definition was offered for scientific processes only; my point is that such a definition ignores the element by which colour is colour.

^{page 456 note 1} Problems of Philosophy, p. 149.