These are very abstract thoughts; and it is pertinent to notice that the most solemn religious terms, and the most striking expressions of admiration, and poetical phrases of love, have their source in verbal roots, indicative of acts and conditions palpable to the senses.
But I am approaching too closely to matters of high import. I am drawn by the word Infinite. Aristotle said truly, “the Infinite attracts.” He was thinking of that other infinite, which is not the one intended by astronomers; but for myself the infinite in nature captivates me so powerfully that I find it difficult to touch earth again. Let us walk in beaten paths; let us endeavour to grasp the meaning of the more simple words learnt mechanically at school, such as those denoting abstraction as well as nouns, and terms both general and particular; and let us see to what phase of thought and speech these grammatical exercises will carry us.
Each palpable object is known to us according as it affects our senses, that is to say, by its properties; all impalpable objects cannot be known otherwise than by their qualities; but nothing exists in nature, whether palpable or impalpable, that has only one property or one quality, each object has several; an object as it exists in reality is concrete, and has a concrete name. If we wished to consider only one of its attributes, we should have to take that apart and isolate it, in order to fix our thoughts exclusively on that; “we must drop that of which the attributes are attributes.”[55] We see white snow, white chalk, white milk, we have the sensation of the white colour; but to take whiteness apart from the snow, the chalk, and the milk, is an operation which requires an instrument, a means, this we possess in a word, viz., the word white. Without that word we should have the sensation of whiteness, but not the idea; it is the word white, whilst separating the white colour from the snow, the chalk, and the milk, that gives us the abstract idea as well as the abstract term whiteness. This mental act is called abstraction: and it is by this process of abstraction that we really arrive at the true knowledge of anything, apart from the sensation of it only.
Here is another example of abstraction. Let us suppose that two persons are in one room, and that there are in the room two windows, two doors, two tables and two chairs. Let us try to obliterate in our mind the persons, the windows, the doors, the tables and the chairs; nothing now remains but the abstraction two. Now two, as such, apart from objects, does not exist in nature; still it is a conception we can retain in our mind, and this abstract idea can be incorporated in the abstract word two.
These two examples of abstraction tell us but little of what is meant by it; and although they teach us little of the part abstraction plays in our mental life, they are correct from a logical point of view, and clearly demonstrate the impossibility of retaining a thought apart from the word expressing it, since evidently the representation of two and of whiteness could not have been made if the words had been lacking.
The faculty of abstraction has no doubt taken time to develop in man, and the absence of abstract words and consequently of abstract ideas was complete in primitive man as it now is in our very young children. The faculties of brutes can by no means attain to abstraction. One reason, amongst others, why we have no ground to think brutes have abstract general ideas is that they do not speak, that they have no use of the words without which it is impossible to carry out the operation which I have just described, and to cause a conception to arise from a sensation.
When, in our early days, our parents gave us instruction on the three divisions of natural history, and explained to us of what they consisted, we did not suspect that a period of immense length had elapsed before man succeeded in thus skilfully classifying the vast mass of names in the manner which struck us as so natural and inevitable. Many thousands of objects were before us, each one entitled to bear an expressive name; and in proportion as our knowledge of things increased was science called upon to furnish new terms; their name became legion and memory failed to retain them. It therefore became a necessity to classify the objects of a common nature under one name; hence the evolution of the terms animal, vegetable and mineral, which relieved us from the burden of enumerating all the objects composing genus and species; then in speaking of them to others we use the generic term, which at the same time presents the image to our own minds. Thus when we wish to denote men having the same nationality as ourselves we employ the collective term compatriot; in the same way the word furniture includes all that serves to furnish our rooms. By the help of this ingenious combination we relieve our memories of a mass of encumbering words, we economise our time and our powers, and simplify the machinery of our thoughts.
This is evidently an advantage. But now a difficulty presents itself. When employing these general terms, such as vegetable, animal, the human race, we are speaking of things of which we are ignorant, and are therefore for us as if they had no existence. We cannot have a complete knowledge of vegetables since that word comprehends all plants and trees on the earth; neither of animals, since “animal” includes not only all beasts lacking reason but also man who is endowed with it. We are equally ignorant of the human race, since it is composed of all human creatures, past, present and to come. It is evident that we only know individual persons and things, such as this fir tree or that oak, this horse, this cow, Paul or James, and we know them because we are in a position to distinguish them by naming them, or indicating them.