The British empiricist John Locke expounds the conditions of knowledge in his Essay Concerning Human Understanding (1690) and denies innate ideas in human reason. He holds that as a „rational creature“ man employs his „faculties of knowledge“ to receive and interpret information.1

The one source for knowledge according to Locke is experience and not primarily reason as Spinoza claims in his Ethics (Ip30d). The term “mind” is futile if it isn’t explained in retrospect through the ways it operates. Locke holds that the human mind is a clean slate, a „tabula rasa2, onto which experiences of the senses are inscribed. Principles and ideas are the result of sensual perception that are experienced through reason. The world of the human mind is strictly separated from the external world of objects. They are mental representations of sensory perception3 gained through experience, acquired through the mind, i.e. not innate, and thus become part of our knowledge.

Locke distinguishes „simple ideas“ from „complex ideas“.4 „Simple ideas“ come from sensations (stimulus). „Complex ideas“ are subdivided into three categories of relations, modes and substances.5 Interestingly, Locke claims that „complex ideas” are made up of several simple ones put together that are interpreted as sensations by our consciousness. Empirical knowledge is gained from the perception of things (sensation) and the inner operation of the mind (reflection).6

Thus, knowledge is interpreted perception of ideas in Locke’s line of thinking:

„Knowledge then seems to me to be nothing but the perception of the connection of and agreement, or disagreement and repugnancy of any of our Ideas. In this alone it consists. Where this perception is, there is knowledge, and where it is not, there, though we may fancy, guess or believe, yet we always come short of knowledge.”7

1 John Locke: Essay Concerning Human Understanding I, 3.12.

2 Ibid II, 1. 2.

3 Ibid I, 1. 8.

4 Ibid II, 2. 1.

5 Primary qualities vs. secondary qualities; Ibid II, 12. 1, 3 and 7.

6 Ibid II, 1. 2 and 4.

7 Ibid IV, 1. 2.