John Locke (1632-1704) completed a philosophical education at Oxford. Locke declined the offer of a permanent academic position in order to avoid committing himself to a religious order. Having also studied medicine, he served for many years as private physician. A friend of Isaac Newton and Robert Boyle, Locke was also an early member of the Royal Society. He studied and wrote on philosophical, scientific, and political matters throughout his life, in a voluminous correspondence and ample journals.

The fundamental principles of Locke’s philosophy are presented in An Essay Concerning Human Understanding (1690), the culmination of twenty years of reflection on the origins of human knowledge. According to Locke, what we know is always properly understood as the relation between ideas, and he devoted much of the Essay to an extended argument that all of our ideas, simple or complex, are ultimately derived from experience. The consequence of this empiricist approach is that the knowledge of which we are capable is severely limited in its scope and certainty.

Locke held that we have no grounds for complaint about the limitations of our knowledge, since a proper application of our cognitive capacities is enough to guide our action in the practical conduct of life. Further, Locke viewed that all rights begin in the individual property interest created by an investment of labor. The social structure or commonwealth, then, depends for its formation and maintenance on the express consent of those who are governed by its political powers. Majority rule thus becomes the cornerstone of all political order, and dissatisfied citizens reserve a lasting right to revolution. Locke also argued for acceptance of alternative religious convictions.

“An excellent man, like precious metal, is in every way invariable; A villain, like the beams of a balance, is always varying, upwards and downwards.”

“As people are walking all the time, in the same spot, a path appears.”

“What worries you, masters you.”

“Education begins the gentleman, but reading, good company and reflection must finish him.”

“I have always thought the actions of men the best interpreters of their thoughts.”

“If we will disbelieve everything, because we cannot certainly know all things, we shall do much what as wisely as he who would not use his legs, but sit still and perish, because he had no wings to fly.”

“Parents wonder why the streams are bitter, when they themselves have poisoned the fountain.”

“New opinions are always suspected, and usually opposed, without any other reason but because they are not already common.”

“Our incomes are like our shoes; if too small, they gall and pinch us; but if too large, they cause us to stumble and to trip.”

“Reading furnishes the mind only with materials of knowledge; it is thinking that makes what we read ours.”

“The discipline of desire is the background of character.”

“There is frequently more to be learned from the unexpected questions of a child than the discourses of men, who talk in a road, according to the notions they have borrowed and the prejudices of their education.”

“This tendency to cruelty should be watched in them children, and if they incline to any such cruelty, they should be taught the contrary usage. For the custom of tormenting and killing other animals will, by degrees, harden their hearts even towards men… And they, who delight in the suffering and destruction of inferior creatures, will not be apt to be very compassionate or benign to those of their own kind. Children should from the beginning be brought up in an abhorrence of killing or tormenting living beings… And indeed, I think people from their cradles should be tender to all sensible creatures… All the entertainment and talk of History is of nothing but fighting and killing; and the honor and renown that is bestowed on conquerors, who, for the most part, are but the great butchers of mankind, further mislead youth.”