Title page for the fourth edition of John Lock...
The fourth edition of John Locke’s Essay Concerning Human Understanding

John Locke (1632-1704) was a British thinker and physician who had a profound influence on Western philosophy, particularly within so-called British Empiricism and the Enlightenment.

Locke believed the human infant enters the world with a tabula rasa—that is, a blank slate.

For Locke, we inherit nothing more than physical characteristics and a basic sense of goodness. This makes the mind free and equal among different individuals, leaning not through innate ideas but through sensory experience.

Although this may seem somewhat speculative today, especially among those interested in neuropsychology, Locke himself argued against abstract speculation in favor of recognizing the limits of knowledge gained through direct experience.

Interestingly, Locke asserted that we can only know about an object’s “primary qualities” of size, shape, and motion because these qualities must exist independent of perception.

We can never know anything about an object’s “secondary qualities” of color, taste, smell, warmth, texture, and sound because these are products of the object’s interaction with our senses—they do not reside in the object itself.

In a way, Locke’s theory of knowledge wasn’t too new. Asian and Greek philosophy had postulated similar ideas centuries before. Islamic thinkers had considered the idea of the tabula rasa during the Middle Ages. And Christian scholastics had been engaged in a complicated, ongoing discussion about empiricism and universals.

To his credit, Locke’s practicality didn’t close him off to the possibility of God’s existence. In his Essay Concerning Human Understanding (1690), he argued for the “reasonableness” of the idea of God.

Locke, in fact, had a remarkably progressive view of religious tolerance.

Unlike some contemporary – I would say arrogant – materialists, Locke maintained that human beings were inadequate to accurately assess the truth claims forwarded by another person or group.

Even if this were possible, Locke believed we cannot force religious belief onto another person. As the old saying goes, “You can take a horse to water but you can’t make him drink.”

Locke also thought that coerced religious conformity would lead to increased social disorder while diversity would promote peace.ยน

ยน Adapted from Wikipedia:

Locke, writing hisย Letters Concerning Tolerationย (1689โ€“1692) in the aftermath of theย European wars of religion, formulated a classic reasoning for religious tolerance. Three arguments are central: (1) Earthly judges, the state in particular, and human beings generally, cannot dependably evaluate the truth-claims of competing religious standpoints; (2) Even if they could, enforcing a single “true religion” would not have the desired effect, because belief cannot be compelled by violence; (3) Coercing religious uniformity would lead to more social disorder than allowing diversity.