DEFINITIONS OF PSYCHOLOGY
Let us resume the study of the preceding ideas in another form. Since, moreover, to define mind is at the same time to define psychology, let us seek for the truth which we can glean from the definitions of this science. Our object is not to discover an exact definition, but to make use of those already existing.
To define psychology is to describe the features of the domain over which this science holds sway, and at the same time to indicate the boundaries which separate it from its neighbours. At first sight this is an affair of geometric survey, presenting no kind of difficulty; for psychology does not merge by insensible transitions into the neighbouring sciences, as physics does with chemistry, for example, or chemistry with biology.
To all the sciences of external nature psychology offers the violent opposition of the moral to the physical world. It cannot be put in line with the physical sciences. It occupies, on the contrary, a position apart. It is the starting point, the most abstract and simple of the moral sciences; and it bears the same relation to them that mechanics does to the physical.
All this is doubtless true; and yet a very great difficulty has been experienced in condensing into a clear definition the essence of psychology. This is proved by the multiplicity of definitions attempted. They are so many because none of them has proved completely satisfactory. Their abundance shows their insufficiency. I will try to introduce a little order into these attempts, and propose to distribute the definitions of psychology into the following categories:—
| 1. | The definition by substance; the metaphysical definition par excellence. |
| 2. | The definition by enumeration. |
| 3. | " " method. |
| 4. | " " degree of certainty. |
| 5. | " " content. |
| 6. | " " point of view. |
| 7. | " " the peculiar nature of mental laws. |
We will rapidly run through this series of efforts at definition, and shall criticise and reject nearly the whole of them; for the last alone seems exact—that is to say, in harmony with the ideas laid down above.
Metaphysical definition has to-day taken a slightly archaistic turn. Psychology used to be considered as the science of the soul. This is quite abandoned. Modern authors have adopted the expression and also the idea of Lange,[33] who was, I think, the first to declare that we ought to cultivate a soulless psychology. This categorical declaration caused an uproar, and a few ill-informed persons interpreted it to mean that the new psychology which has spread in France under cover of the name of Ribot, sought to deny the existence of the soul, and was calculated to incline towards materialism. This is an error.
It is very possible, indeed, that several adepts of the new or experimental psychology may be materialists from inward conviction. The exclusive cultivation of external facts, of phenomena termed material, evidently tends—this is a mystery to none—to incline the mind towards the metaphysical doctrine of materialism. But, after making this avowal, it is right to add at once that psychology, as a science of facts, is the vassal of no metaphysical doctrine. It is neither spiritualist, materialist, nor monist, but a science of facts solely. Ribot and his pupils have proclaimed this aloud at every opportunity. Consequently it must be recognised that the rather amphibological expression "soulless psychology" implies no negation of the existence of the soul. It is—and this is quite a different thing—rather an attitude of reserve in regard to this problem. We do not solve this problem; we put it on one side.
And, certainly, we are right to do so. The soul, viewed as a substance—that is, as a something distinct from psychical phenomena, which, while being their cause and support, yet remains inaccessible to our direct means of cognition—is only an hypothesis, and it cannot serve as objective to a science of facts. This would imply a contradiction in terms.