John Locke (1632-1704) was a political philosopher and theorist active within the Age of Enlightenment and often considered the father of British empiricism. This entry focuses on Locke’s empiricism and empiricist theory of mind.

Empiricism Versus Rationalism

In his essay Concerning Human Understanding (1689), Locke attempted to rebut the rationalist’s argument that human beings are born with innate ideas, and by attempting to do so he laid down the foundation for modern empiricist thought. Locke’s views stood in contrast to ideas presented by other prominent thinkers such as Rene Descartes (1596-1650) who argued that humans are born with innate ideas and that reason, rather than experience, is a primary means of acquiring knowledge. Locke’s idea was certainly not new as empirical thought had been defended previously by Francis Bacon (1561-1626), Thomas Hobbes (1588-1679), and even Aristotle (384-322 BC). What made Locke unique was that he was the first philosopher to provide a comprehensive defense of empiricism, and although he viewed experience to be the principal source of knowledge, Locke did not dismiss the importance of reasoning within a person’s acquisition of knowledge. Each person has been born with the capacity for reasoning and that access to the right education is critical to one’s intellectual development.

The Tabula Rasa

To Locke, there is no such thing as innate knowledge, and he claimed that the human mind is a tabula rasa (a blank slate) prior to sense experience. When one observes newborn babies it is clear that they do not bring ideas into the world with them. The infant’s mind is completely blank and everything he will know will come through his experience of the world around him. Despite being blank, the mind still possesses inherent capacities, predispositions, and inclinations prior to receiving any ideas from sensation that will be used to learn about the world. Only by venturing through life and experiencing the world do ideas enter into the mind.

Empiricist Theory of Mind

As part of his empiricist theory of mind, Locke attempted to account for the contents of the mind, which led him to propose several notions of idea acquisition. Experience (sensation and reflection), articulated Locke, provides the individual with minimal units of mental content, which can be combined into more complex ideas, which then themselves can be further combined into even more complex ideas. From such convictions, Locke attempted to account for the construction of ideas such as space, infinity, God, and causation received in experience.

Locke held there to be two distinct types of experience: Outer and Inner experience. Outer experience (sensation) provides a person with ideas through the five senses: sight provides ideas of colour, hearing gives one ideas of sound, and so on. All of this is based upon experience: a person’s idea of a particular shade of yellow is a product of seeing a flower while hearing the sound of a whistle is a product of being in close proximity to a sport’s field. Inner experience (reflection) involves the mind’s constant performance of “operations.” Locke believed that a person is able to experience her mind performing actions (such as imagination, desire, doubt, remembrance, etc.), which leads to her receiving ideas of reflection. These are ideas such as memory, imagination, desire, doubt, judgment, and choice.

Locke classified complex ideas into three categories: substances, modes, and relations. Ideas of substances are ideas of things that are thought to exist independently, such as objects like desks, cars, and mountains. Beneath this category there are also collective substances, which consist of various individual substances coming together to form a whole: a group of houses forms a town, a group of people forms a sport’s team. Ideas of modes, said Locke, are ideas of things which are in some manner dependent on substances. There are two types of modes: simple and mixed. The former is constructed by combining a large number of a single type of simple ideas together. An example Locke cites is the simple idea of unity: the person’s idea of the number seven is a simple mode constructed by linking seven simple ideas of unity together. This mode Locke used to explain how people think of topics such as number, space, time, pleasure and pain, and cognition. The latter mixed mode, moreover, is the process of combining simple ideas of more than one type, which includes moral ideas such as ideas of theft, murder, duty, and so on. Ideas of relations are ideas that involve more than one substance, which involves relations by conceiving of a subject (a king) in relationship to some subjects (the common people or servants). For Locke, all of these ideas can be broken down into simple ideas received in sensation and reflection.

Primary and Secondary Qualities

Locke also defined primary and secondary qualities. He stated that a person can only receive information about the world through her senses, and that this information is of two kinds: primary and secondary qualities. An object’s primary qualities (such as its height, length, breadth, weight, location, motion, or mass) are objective and exist independently of the person observing it. Secondary qualities (such as its colour, texture, smell sound, or taste) may differ between observers: the exact same ball, for instance, might appear blue to one person and purple to another, but both will agree on its size.

References and Recommended Readings

Connolly, P. John Locke (1632—1704). Available.

Weeks, M., Baiasu, R., Fletcher, R., Szudek, A. & Talbot, M. 2019. How Philosophy Works. London: Dorling Kindersley Ltd.