In pursuing this plan, the first step will be to exhibit the constitution and laws of mind, as the chief and most wonderful exhibition of the grand design of its Author.
CHAPTER VII.
DIVERSITIES IN SYSTEMS OF MENTAL PHILOSOPHY.
We are now to commence an examination of the various powers and operations of the human mind, for the purpose of illustrating the grand aim of the Author in the creation of all things.
In pursuing this course, it is needful, first, to refer to the apparent diversities in systems of mental philosophy, for the purpose of justifying the classification and the terms to be employed hereafter.
There is nothing more hackneyed than the complaints against metaphysics as abstruse, difficult of comprehension, and unpractical, while the various writers on this science seem more or less divided into opposing schools. Notwithstanding this, there are reasons for maintaining a real agreement in all systems of mental philosophy, at least in essentials, and the following considerations lead to such a conclusion:
In the first place, the nature of the subject investigated would necessarily tend to such a result; for that subject is the human mind, not in its specific peculiarities, but in those generic phenomena which are common to all minds; just as the natural philosopher investigates those properties of matter which are common to a class, and not the specific peculiarities that distinguish individual masses or particles. Now, as those who direct their investigations to mental phenomena are all drawing a picture from the same pattern, it is properly inferred that in the main outlines there must be a general resemblance.
Another reason for this conclusion is the mode of investigation pursued. It is simply observing, first, the phenomena of our own minds, and then comparing them with those of other minds as exhibited in looks, words, and actions, and thus educing generic resemblances and specific differences. It is the generic resemblances only that constitute the faculties and laws of mind which are to be described, classified, and named.
Another reason for inferring such an agreement of systems is the fact, not only that all human minds have common phenomena, but that they have provided themselves with terms to express them, so that they succeed in so far understanding each other as to make comparisons of their mental experience.
The same agreement may be inferred, also, when we consider that mental philosophy treats, not of new ideas, or new combinations of ideas, but of knowledge which is already in the mind. The process to be pursued, then, involves a reference to what we have ourselves experienced; it is an examination of our own feelings, thoughts, and volitions. These are subjects of which we are competent judges, and in regard to which we can be certain as to what is correct or incorrect, more than we can be in reference to any other kind of knowledge.