John Locke


One of the common things among Descartes, Spinoza and Leibniz is that they are all rationalists. Rationalism is the system of thought, which believes in reason as a primary source of knowledge. A rationalist may also believe that man has certain innate ideas, which exist in his mind a priori, i.e. not derived from experience. Descartes was French, Spinoza was Dutch and Leibniz was German, so we often refer to this movement as Continental Rationalism.

As opposed to rationalism, another system of thought appeared in the later half of seventeenth century, which declared experience as the primary source of all human knowledge. Only the information we receive through our senses is what we can know about the world. This system of philosophy is known as Empiricism and John Locke was its founder. It was extended by Berkeley and Hume. Locke was English, Berkeley was Irish, and Hume was Scottish. Hence, we refer to their philosophy as British Empiricism. As the rationalists admired the abstract mathematical reasoning, the empiricists were inspired by the development of science and its stress on observation and experiment. Their philosophy was also crucial to the development of psychology.

John Locke was one of the most influential men of all times. His contributions have a very wide range; he was one of the initiators of the eighteenth century liberalism. He advocated democracy, religious toleration, economic freedom, and educational progress. Despite his remarkable additions to human thought and development, we shall mostly restrict ourselves to Locke as the founder of empiricism.

Locke’s most important work is An Essay Concerning Human Understanding. He begins with ideas. An idea is a broad concept and includes all the objects of understanding and contents of knowledge (sensory images, thoughts and memories, hopes and desires, and political and moral views etc, are all included in the term ‘idea’.) Locke inquires about the source of these ideas: from where do we derive them?

A prevalent answer was that many ideas are innate. Locke utilizes a great part of his book in refuting innate ideas. There are no innate ideas present in the human mind. He maintains that neither logic and metaphysics nor principles of morality are stamped on our mind from birth. The wide diversity of human views on these matters itself is a strong argument against this concept, but even if an idea is universal and present among all persons, it doesn’t mean that the idea is innate. In fact, the generality of such ideas can be better explained in terms of self-evidence and shared experience. Locke’s main argument is that since mind is defined as consciousness, there can be nothing in the mind of which it is not aware. If innate ideas like God and causality are present from birth, then even infants, savages and untutored men must be aware of them, but we find even the most learned philosophers differing on these problems. Hence, there are no such innate ideas.[1] It must be understood that Locke is denying innate ideas, not innate faculties. The mind has no innate ideas, but it has innate faculties: it perceives, remembers, and combines the ideas that come to it from without; it also desires, deliberates, and wills; and these mental activities are themselves the source of a new class of ideas, as we shall see.

After a detailed refutation, Locke gives the answer that he considers to be correct: all ideas are derived from experience through senses. He calls the mind at birth a tabula rasa, an empty slate. It is bare of all knowledge; it is an unfurnished room. This vacant room is furnished with ideas by two means: sensation and reflection. Sensation depends wholly upon senses, and is the perception of the external objects, e.g. ‘soft’, ‘green’, ‘sour’, ‘hot’ are all ideas of sensation. Reflection is concerned with the internal operations of our mind, it is an ‘internal sense’ by which we think about what we perceive and feel. When we form ideas by thinking, reasoning, believing or doubting, we are using reflection.

Locke says that what we can perceive directly are only simple ideas. For example, when I am eating an apple, I do not perceive the ‘apple’ as a unit idea. I receive a whole series of simple sensations: there is something green and round, and tastes juicy and sharp. It is only when these simple ideas are experienced a large number of times that an idea of ‘apple’ is formed. Hence, ‘apple’ is a complex idea. Since all knowledge comes through simple ideas, all knowledge must be reducible to simple ideas. An immediate objection is raised that if all our knowledge comes from experience, then how can we have an idea of non-existent things like unicorns, mermaids, and vampires. The answer is that our mind classifies and organizes things, and often does a ‘cut and paste job’. That is, it takes different simple ideas and joins them together to form complex ideas, which do not exist in reality. We can think of a ‘mermaid’ only because we have an idea of a woman and a fish. We can conceive a ‘unicorn’ because we already have ideas of a horn and a horse. [And, as a psychologist might add, we can think of God as a kind father because we have ideas of kindness and father.]

Locke also classifies between primary qualities and secondary qualities. Primary qualities are the intrinsic feature of an object, such as its mass, figure, motion, volume, number etc Secondary qualities are not present in the thing itself, but produce in us the ideas of color, sound, smell, taste etc. An apple is intrinsically round but it is not intrinsically red; it is one’s own subjective experience. You may see the apple as green but a colorblind person will see a different color. But you would both agree that its mass is 5 grams. You may perceive a lemon as sweet or sour, but either it is round or it is not. Therefore, secondary qualities vary from person to person but primary qualities do not. This classification was very useful in Physics and dominated the scientific thought for a long time, although it was rejected by philosophers succeeding Locke. This classification was also meant to clarify the problem of perceptual illusion. Locke maintained that this illusion is restricted to secondary qualities and hence, is purely subjective.

Locke initiated empiricism as a system of philosophy but he himself didn’t properly apply its principles. Berkeley developed empiricism after Locke and in Hume it reached its climax.
In his political philosophy, Locke, like Hobbes, also discusses the origin of a State. Locke imagines a primitive condition in which individuals exist without any mutual authority, and rely upon their own abilities. However, this state is not the state of Hobbes’s war with all against all, because everyone uses the faculty of reason, and is bound by the ‘self-evident laws of nature’. They emerge from this primitive state by a social contract, and gather under the authority of the government. But unlike Hobbes’s social contract, the government is a party of the contract, and the contract is revocable, if the government doesn’t fulfill its terms and conditions.

[1] Psychology, however, maintains that there can be contents in the mind of which we are not consciousness i.e. the unconscious part of mind. However, it was not until the time of Sigmund Freud that the idea of an unconscious mind began to be accepted. Before Freud, Nietzsche had also hinted about the idea of unconscious motives and desires in his writings.