It is hard to draw the line between perceptual and conceptual inferences, or rather to say, in this or that case, to which class the inference belongs, because man, through language, lives in a conceptual atmosphere. Moreover, the same result may, in different cases, be reached by perceptual or by conceptual inference. A child who had seen a great number of ascending balloons might, on seeing a balloon, expect it to ascend by a perceptual inference; but a man, knowing that the balloon was full of a gas lighter than air, might expect it to ascend through the exercise of conceptual inference. And just as in adult civilized life our constructs have more and more conceptual elements built into them, so do our inferences become more and more reasoned. It is probable that in an adult Englishman every inference has a larger or smaller dose of the conceptual element.
With the development of language we state our inferences in the form of propositions, and call them judgments. "Every proposition," says Mr. Sully,[GA] "is made up of two principal parts: (1) the subject, or the name of that about which something is asserted; (2) the predicate, or the name of that which is asserted. Thus, when we affirm, 'This knife is blunt,' we affirm or predicate the fact of being blunt of a certain subject, namely, 'this knife.' Similarly, when we say, 'Air corrodes,' we assert or predicate the power of corroding of the subject 'air.'" The proposition always involves conceptual elements; for the predicate of a proposition is always an abstract idea or general notion.
Propositions so formed may then become links in a chain of reasoning. "To reason is," says Mr. Sully,[GB] "to pass from a certain judgment or certain judgments to a new one." And so passing on from judgment to judgment, we may ascend to the higher levels of abstract thought. According to Mr. Sully's definition, therefore, we start from a judgment or judgments in the process of reasoning. The formation of a judgment (conceptual inference) is, however, the first step in a continuous process; and I propose, under this term, "reason,"[GC] to include this first step also. The formation of a conceptual inference I regard as the first stage of reason. Any mental process involving conceptual inference I shall call rational.
In contradistinction to this, I shall use the term "intelligence" for the processes by which perceptual inferences are reached. An intelligent act is an act performed as the outcome of merely perceptual inference. A rational act is the outcome of an inference which contains a conceptual element.
CHAPTER IX.
MENTAL PROCESSES IN ANIMALS: THEIR POWERS OF PERCEPTION AND INTELLIGENCE.
Two things I have been especially anxious to bring out prominently in the foregoing chapter: first, that the world we see around us is a joint product of two factors—the outward existence, on the one hand, and our active mind on the other; and secondly, that our mental processes and products fall under two categories—on the one hand, perception, giving rise to percepts, perceptual inferences, and intelligence, and on the other, conception (involving the analysis of phenomena), giving rise to concepts, conceptual inferences, and reason.
Now, I am anxious that the former—to take that first—should be laid hold of and really grasped as an indubitable fact. It is implied in the word "phenomena," that is to say, appearances. We can only know the world as it appears to us; and the world is for us what it appears. There is nothing here in conflict with common sense; the practical reality of phenomena is altered no whit. Suppose philosophy tries to get behind phenomena, so as to get a peep at the world beyond. Suppose Carlyle tells us that "All visible things are emblems; what thou seest is not there on its own account; strictly taken, is not there [as such] at all; matter exists only spiritually, and to represent some idea and body it forth." Has he altered the reality of the phenomena themselves? Not in the smallest degree. Suppose the materialist gives us his analysis of phenomena. Are not the phenomena he analyzes still the same, still equally real? No matter how far he analyzes phenomena, behind phenomena he cannot get. The materialist resolves all phenomena into matter in motion or into energy, and says that these are the only real existences. But they are no more real (they are a good deal less real to most of us) than the phenomena with which he started. How can the results of analysis be more real than that which is analyzed? Moreover, the matter and energy are still phenomena, and involve, as such, the percipient mind. Do what you will, you cannot get rid of the mental factor in phenomena.
It is possible that my use of the word "construct," my saying that the object is a thing which each of us constructs at the suggestion of certain sense-stimuli, may lead some to suppose that the process is in some sense an arbitrary one. This, however, would be a misconception. The process under normal conditions is just as inevitable as is, under normal conditions, the fall of a stone to the ground. The law of construction for human-folk is as much a law of nature as the law of gravitation. Both laws are condensed statements of the facts of the case. There is nothing arbitrary, lawless, or unnatural in the one or the other; the phrase merely emphasizes the essential presence of the mental factor.
If this principle be once thoroughly grasped, it will be seen how shallow and misleading is the view that the world is just reflected in consciousness unchanged as in a mirror, or faithfully photographed as on a sensitive plate. This is to reduce the human mind, which is surely no whit less complex than the human body, to the condition of a mere passive recipient instead of a vital and active agent in the construction of man's world.