As to the other fundamental science, LOGIC, the same remarks may be repeated. Of debated questions, a certain number pertain properly to logic; yet most of these relate to logic at its points of contact with psychology. Since we have got out of the narrow round of the Aristotelian syllogism, we have agreed to call logic ars artium, or, better still, scientia scientiarum, the science that deals with the sciences altogether—both object sciences and subject sciences. Now this I take to be a study quite apart from psychology in particular, although, as I have said, touching it at several points. It reviews all science and all knowledge, as to its structure, method, arrangement, classification, probation, enlargement. It deals in generalities the most general of any. By taking up what belongs to all knowledge, it seems to rise above the matter of knowledge to the region of pure form; it demands, therefore, a peculiar subtlety of handling, and may easily land us, as we are all aware, in knotty questions and quagmires.
Now what I have to repeat in this connection is, that you should, in your debates, overhaul portions or chapters of systematic logic, with a view to present the difficulties in their natural position in the subject. You might, for example, take up the question as to the Province of logic, with its divisions, parts, and order—all which admit of many various views—and bring forward the vexed controversies under lights favourable to their resolution. Regarding logic as an aid to the faculties in tackling whatever is abstruse, you should endeavour to cultivate and enhance its powers, in this particular, by detailed exposition and criticism of all its canons and prescriptions. The department of Classification is a good instance; a region full of delicate subtleties as well as “bread-and-butter” applications.
It is in this last view of logic that we can canvass philosophical systems upon the ground of their method or procedure alone. Looking at the absence, in any given system, of the arts and precautions that are indispensable to the establishment of truth in the special case, we may pronounce against it, a priori; we know that such a system can be true only by accident, or else by miracle. We may reasonably demand of a system-builder—Is he in the narrow way that leadeth to truth, or in the broad way that leadeth somewhere else?
I have said that I consider the connection between Logic and Psychology to be but slender, although not unimportant. The amount and nature of this connection would reward a careful consideration. There would be considerable difficulty in seeing any connection at all between the Aristotelian Syllogism and psychology, but for the high-sounding designations appended to the notion and the proposition—simple apprehension and judgment—of which I fail to discover the propriety or relevance. I know that Grote gave a very profound turn to the employment of the