The first and perhaps greatest classic of modern empiricism is John Locke’s Essay Concerning Human Understanding
(1690). The work is divided into four books. The first criticizes innate knowledge, the second explains the origin of ideas in experience, the third discusses language and the fourth the nature and extent of knowledge. The result is an extended discussion of both versions of empiricism. In this chapter, we will focus on his def ence of conceptual empiricism and his conception of scientific knowledge and its limits. Other aspects of his theory will be considered in Chapter 2
in connection with Berkeley’s criticisms in Chapter 2
Locke’s criticism of innate ideas and knowledge is part of his general theory of scientific knowledge. He opposed Descartes’s rationalist theory and the Aristotelian-medieval theory Among the examples of innate truths he considers are:
- (1) Whatever is, is.
- (2) It is impossible for the same thing to be and not to be.
- (3) Do as one would be done to.
- (4) Virtue is the best worship of God.
- (5) God exists.
Locke’s discussion is divided into three parts. First, he attacks the claim that there are innate speculative truths such as (1) and (2). He rejects Descartes’s claim that these are general maxims presupposed by all knowledge and so unlearned. Locke holds that we can have knowledge without knowing general propositions such as (1) and (2) and hence do not have to posit them as innate. Secondly, he considers the case for innate practical or moral principles such as (3) and (4). He argues that it is always reasonable to ask for a reason for a moral claim. Even (3) (the “golden rule”) is not seen to be true as soon as it is understood (like ‘Blue is not red’, which Locke holds is self-evident). One might understand the rule, yet still ask for a reason why it should be believed. As a result, the claim that all innate moral truths are self-evident and need no reason is false. Thirdly, he argues that a belief cannot be innate unless its ideas are also innate, but that the ideas in standard examples (such as (5), ‘God exists’) are not innate, but acquired. His general conclusions are: (a) innatism is unfounded, since we can explain all our ideas on the basis of experience; (b) the criteria for innate knowledge and the notion itself are hopelessly unclear; and (c) this unclarity can only lead to dogmatism. He says that once men found principles they could not doubt, it was “a short and easy way to conclude them innate”. This eased “the lazy from the pains of search” and stopped enquiry into “all that was once styled innate” (Essay: I iv 24). Knowledge depends “upon the right use of those powers nature has bestowed upon us” and not on inborn principles or on what other men know. We may as easily “hope to see with other men’s eyes, as to know by other men’s understandings”. “Suchborrowed wealth, like fairy-money, though it were gold in the hand from which he received it, will be but leaves and dust when it comes to use” (I iv 22, 23).
Critics sometimes argue that he does not prove in each case that the principles (or their ideas) are not innate, but he never claims to be able to prove this. He says he is offering an alternative and more plausible theory of the origin of our ideas (and hence knowledge). So long as this theory is not demonstrated to be false by the proponents of innateness, they have not proved their case, but have only shown that it is a possible account of the matter.
I shall concentrate on Locke’s criticism of innate speculative truths. His main target is Descartes, who held that innatism is necessary to defend the reality of scientific knowledge, but both their theories have their roots in the medieval theory of science. Let us first look at this medieval theory.
Following Aristotle, the scholastics held that all ideas derive from experience or, as Thomas Aquinas (1224-1274) put it, “There is nothing in the understanding that was not previously in the senses” (Copleston 1952: 393). They held that the world of nature contains objects with form and matter; when we perceive them, we become aware of the forms without the matter, which then become the materials of our knowledge. We can be assured that this knowledge is genuine since there is a correspondence between the forms in our minds and the forms in reality The view may be summarized in three theses.
- (i) Perception is the reception of the form of an object without its matter. Physical objects differ in their form and exist because this form is instantiated in matter. A rose, for instance, is matter with a colour and shape that distinguishes it from a lilac or a rabbit. When we perceive it, we are aware of these distinguishing characteristics without the matter.
- (ii) By abstracting some of the qualities of the object from others, we acquire new concepts, such as the concepts of red, petals, flower and even the more general concept of a plant. All simple concepts are acquired by a similar process. Then, by combining these abstract ideas, we form complex ideas of objects we have not experienced, such as the idea of God and of things that do not exist at all, for example, the ideas of unicorns and centaurs.
- (iii) The basic ideas, however, such as the ideas of a rose, a horse and a man, correspond to features in the objects. The result is that perception gives us adequate ideas of natural objects and their species. By further comparison and generalization, we arrive at general principles and ultimately laws of nature and science. Since the ideas derive from the transference of forms in nature to the mind, we can be assured that there is a correspondence between them and nature, and that our science is genuine.
We may call (i) the reception thesis, (ii) the abstraction thesis and (iii) the correspondence thesis.
This Aristotelian theory was accepted in its broad outlines for almost two thousand years until the new science of the seventeenth century called it into question. This “new science” was actually an extension of ancient atomism, which held that objects are not composed of a material and a formal element, but of insensible particles in motion. The colour and shape of a rose are a result of a certain configuration of particles or corpuscles (which we would now term atoms and molecules), which are themselves neither roses nor red. Descartes accepted this, although he rejected the ancient atomists’ theory that things are composed of void or empty space as well as particles. He thought every part of space is filled with particles that move together somewhat the way in which oil moves in water when it is stirred. But he agreed with most of the scientists at the time that physical objects are systems of insensible particles rather than substantial entities composed of matter and form. As a result, he rejected the reception theory of perception. Perception occurs when corpuscles from the object strike the senses, causing particles in the body to move until an image is formed in the mind. Perception is not the transference of a form from object to mind, but occurs by impulse. Furthermore, the picture we have of the world with its shapes and colours and apparently solid objects is mistaken; it is actually composed of colourless extended particles in motion (which are always in touch with other particles, since there is no vacuum). The world is not as it appears, but radically different.
In explaining this theory, Descartes compares perceptual ideas to words. Just as words do not resemble the qualities they represent, so ideas do not resemble their objects. They are signs that signal their presence and lead us to avoid or pursue them. But as resemblances they are “false”. He also compares us to blind men who use a cane. There is no more resemblance between our ideas and reality than there is between the blind man’s sensations of the end of his cane and reality. This led him to conclude that if we are to have an adequate scientific conception of the world, the senses cannot be trusted as the source of our concepts, so he rejected the abstraction thesis as well. To save the reality of knowledge, he holds that geometrical and scientific concepts (as well as metaphysical concepts such as the ideas of substance and God) do not arise from experience, but are innate. And, since he can prove a priori that God exists and is good, we can be assured that these ideas are adequate and correspond to the world. The result is that even though he rejects the reception thesis, Descartes still accepts the correspondence thesis, but at the expense of the abstraction thesis. Concepts such as those of triangularity, extension, substance, infinity and even of God are not derived from experience, but are part of the mind’s native equipment. But he does not go so far as to argue that all knowledge is innate. He thinks perception can be trusted if it is carefully examined in the light of innate ideas and the principles based on them, and after we have validated its reliability by appeal to God’s will. The result is a science of reality based in part on experience, but ultimately certified on the basis of innate ideas and a priori proofs.
Locke agrees that the Aristotelian-scholastic theory of perception is mistaken. Simple ideas like those of the sweetness and whiteness of sugar do not resemble qualities in sugar; at best they are caused by powers in it to produce them, but this is only a minimal correspondence. Unlike Descartes, however, he continues to accept abstraction as the source of ideas. Our ideas may or may not correspond to external objects, but we can know this only by appealing to experience. Locke, in other words, rejects the reception thesis, but accepts the abstraction thesis, and accepts the correspondence thesis only in severely modified form. Nothing in our ideas guarantees that they correspond with reality, since abstraction is a selective process and may lead us astray.
This might seem a reasonable alternative to the scholastic theory, but it has a troubling aspect. Descartes argues that innateness will allow our scientific conclusions to be known with certainty, but Locke is forced to give this up. This means that the medieval sense of science as absolute certainty must give way to probability and analogical reasoning, and since Locke continues to hold that knowledge must be certain, this implies that there is no scientific knowledge. This skeptical conclusion did not bother Locke or many of his contemporaries, but it has worried others. We shall say more about it in § “Nominal and real essences” (p. 26).
Locke offers several arguments against innateness:
- He argues that no truths are universally accepted as we would expect if they were innate in all human beings. Many people do not have a European conception of God, and children and idiots have none at all. Children and primitive peoples also do not seem to have highly abstract ideas such as those of identity and infinity, even though these are thought to be the most basic innate ideas of all. (He gives similar arguments against innate practical or moral principles.) Furthermore, even if there were universally accepted principles, this would not prove them innate, since they and their ideas might be acquired by common experience.
- Defenders of innatism have an answer to this. They hold that these principles are still in their minds potentially; people who do not seem to have the necessary innate ideas on which they are based have not reflected sufficiently to become aware of them. Locke argues that if this is the case all knowledge is innate, since in order to know something we must have an innate power to become aware of it. Potentiality of awareness is not enough to show that there is innate knowledge. We shall return to this shortly.
- Locke also argues that in order to know that a proposition is true we must have perceived it to be true at some time in the past, where ‘perception’ is taken to imply apprehension or awareness. This implies that at some time prior to birth, we must have been aware of their truth and Locke takes this to be most implausible.
- His main argument is that we do not have to accept innatism in order to explain our ideas. They can be explained by abstraction. The idea of God, for instance, is a complex idea of a thinking substance who is perfect and infinitely powerful, and each of these simpler ideas can be traced back to the perception of external objects (“outer sense”) and the perception of our own minds and its contents (“inner sense”).
Several features of Locke’s position are often overlooked. First, he claims not to offer “undeniable cogent demonstrations” of his theory, as Descartes did, but “to appeal to men’s own unprejudiced experience, and observation” whether his principles are acceptable. He hopes it will be “an edifice uniform” and that he will not have “to shore it up with props and buttresses, leaning on borrowed or begged foundations; or at least, if mine prove a castle in the air, I will endeavour it shall be of a piece, and hang together” (Essay: I iv 25). He develops his alternative theory in Book II by showing in detail how our ideas can be explained on the basis of experience alone.
This leaves room for Descartes’s theory, since Locke does not claim to prove that innatism is false, but it still puts the Cartesian in a difficult position. Descartes claims that his theory can be shown to be true with certainty By showing that there is an alternative theory, Locke puts the innatist in the position of having to prove with certainty that his alternative is unacceptable, since a theory or belief cannot be proved with certainty so long as there is a possible (i.e. consistent) alternative. Furthermore, the Cartesian must prove that it is false without appealing to innatism itself, since this would beg the question. The only other option is to argue that innatism is the more plausible theory to account for the facts and Locke thinks most people will accept his empiricist theory on this ground.
One way to put his view is that he holds that empiricism with abstraction is the more reasonable hypothesis. If a phenomenon can be explained by more than one theory, we cannot prove one over the other with certainty unless we can prove that the other accounts are false, Locke holds that, since there is no direct proof of innatism and empiricism cannot be disproved, the best we can do is to accept the more plausible account, which he thinks is the empiricist one.
Secondly, Locke argues that learning ideas such as those of substance, identity and God requires a great deal of time and depends on learning a language as well. A child may know that “an apple is not fire” because it has the concepts of fire and apple from experience, but it will take years before it will assent to principles such as (2), that is, that it is impossible for the same thing to be and not be at the same time. He might learn the words, but Locke says their meanings are so “large, comprehensive, and abstract” that it will take a great deal longer before he learns their precise meanings and understands the principle itself (Essay: I ii 23).
This too is often overlooked. Descartes’s only argument for innate ideas is that we do not find ideas such as substance and power when we examine external objects, but he restricts his enquiry to what he is aware of at the moment. He gives several examples. One is that we have two ideas of the sun. The senses tell us that it is a small disc in the sky while the intellect tells us that it is “several times larger than the earth”. These cannot both resemble the real sun and reason tells him that the intellectual idea is to be preferred, since it ...