Story of Psychology - Morton Hunt [48]
What made Locke’s Essay historic was his explanation of how we acquire knowledge; the rest of it does not concern us. He set about exploring, differently from his predecessors, how the mind comes by knowledge. First, unlike Descartes and Hobbes, and despite his medical training, he chose not to speculate about the “motions of our spirits, or alteration of our bodies” by which we have sensations, perceptions, or thoughts.32 Either he realized that physiology was still in a primitive state or that psychological processes can be studied at a macro level, ignoring the micro level, as one can study wave mechanics without considering the movements of the molecules making up the waves.
Nor did he rely on formal deductive reasoning, as had Descartes and Spinoza. Instead, he used as nearly empirical an approach as was then available by examining his own experiences and those of others, including children of different ages, asking himself what events take place, and in what sequence, that result in knowledge. He also conducted at least one famous experiment. After putting one hand in a basin of hot water and the other in a basin of cold water, he moved both to a basin of tepid water, which felt cold to one hand and hot to the other. This demonstrated that despite the objective nature of the cause of a perception, our perception of it is subjective and not a replica of the object’s qualities.33
Locke’s first piece of business in the Essay is to attack the doctrine of innate ideas. To Descartes’ argument that the idea of God must be innate, since we do not experience Him directly, Locke replies that it cannot be innate, because some peoples have been found who have no such idea. He suggests a pious—but empirical—alternative: we derive our idea of God from “the visible marks of extraordinary wisdom and power…in all the works of creation.”34 Nor can there be innate principles of right and wrong; history shows so wide a range of moral judgments that they must be socially acquired. Even if some ideas are universal, they are not innate if some other explanation can be found. And it can. He will show “whence the understanding may get all the ideas it has” and, as evidence, “I shall appeal to every one’s own observation and experience.”35
He then states the great primal doctrine of empirical psychology: “Let us then suppose the mind [at birth] to be, as we say, white paper, void of all characters, without any ideas. How comes it to be furnished?…I answer, in one word, from experience. In that, all our knowledge is founded, and from that it ultimately derives itself.”36 (It is often said that Locke spoke of the newborn’s mind as a tabula rasa, but he did not use that term; it was Aquinas’s translation of a phrase in Aristotle.)
Locke says there are two sources of the mind’s “ideas” (the word he uses to refer to everything from perceptions to abstract concepts). They are sensation and reflection (the mind’s own operations on whatever it has acquired; in his words, “all the different actings of our own minds”).
Our sense organs transmit sensations to the mind; these he calls “simple ideas.” From them the mind gradually forms “ideas of reflection” (its recognition of its own ability to perceive, to think, to will, to distinguish between things, to compare, and so on). From the interaction of these two classes of ideas arise all others, including the most complex and abstruse.
Locke goes on at great length to show how this is all that is needed to account for the most remote and difficult concepts. (He apologizes for his prolixity, but says, “I am now too lazy, or too busy, to make it shorter.”) He explains how the mind contemplates simple ideas and puts them together to make complex ones; sees similarities and differences between simple and complex ideas; and uses the recognition of differences to construct still more complex ideas. We derive abstract ideas such as whiteness, for instance, by noticing a quality common to certain different things (a sail,