“How has it happened, that the profound Locke, who, to the great mortification of the metaphysicians, has placed this principle of Aristotle—that nothing enters the mind of man, but through the senses—in the clearest point of view; how is it that all those who, like him, have recognized the absurdity of the system of innate ideas, have not drawn the immediate and necessary consequences? How has it come to pass, that they have not had sufficient courage to apply so clear a principle to all those fanciful chimeras with which the human mind has for such a length of time been so vainly occupied?

— Baron d’Holbach (1770), The System of Nature (pg. 79)

“Bacon, Locke, and Newton are the three greatest men that have ever lived, without any exception.”

— Thomas Jefferson (1789), “Letter to John Trubull”

“Voltaire’s letter on Locke from the Philosophical Letters (1734), which circulated separately as a ‘Letter on the Soul’, which La Mettrie had read, [touched on] Locke’s hypothesis that god might ‘superadd to matter a faculty of thinking’, which gave rise to great controversy in Britain concerning materialism and the nature of the soul.”

— Ann Thomson (1994), “Introduction” to Julien La Mettrie’s writings [4]

“There cannot be any one moral rule proposed, whereof a man may not justly demand a reason.”

— John Locke (1669), An Essay Concerning Human Understanding (Ѻ)

“In all the visible corporeal world we see no chasms or gaps. All quite down from us the descent is by easy steps, and a continued series that in each remove differ very little one from the other. There are fishes that have wings and are not strangers to the airy region; and there are some birds that are inhabitants of the water, whose blood is as cold as fishes. There are animals so near of kin both to birds and beasts that they are in the middle between both. Amphibious animals link the terrestrial and aquatic together; . . . not to mention what is confidently reported of mermaids or sea-men. There are some brutes that seem to have as much reason and knowledge as some that are called men; and the animal and vegetable kingdoms are so nearly joined, that if you will take the lowest of one and the highest of the other, there will scarce be perceived any great difference between them; and so on until we come to the lowest and the most unorganical parts of matter, we shall find everywhere that the several species are linked together, and differ but in almost insensible degrees.”

— John Locke (1869), Essay Concerning Human Understanding (III, chap. 6, §12); cited by Arthur Lovejoy (1933) in The Great Chain of Being (pg. 184)

“I greatly esteem all those who faithfully defend their opinion; but there are so few persons who after the manner they do defend them, appear fully convinced of the opinions they profess, that I am tempted to believe there are more sceptics in the world than are generally imagined.”

— John Locke (c.1670) Publication; cited by Baron d’Holbach (1770) in The System of Nature (pg. 221)

“The actions of men the best interpreters of their thoughts.”

— John Locke (c.1680), Publication

“Heat is a very brisk agitation of the sensible parts of the object, so that what in our sensation is heat in the object is nothing but motion.”

— John Locke (c.1670), “On the Five Senses of Touch” (Ѻ); in: The Works of John Locke in Nine Volumes, Volume Two (Elements of Natural Philosophy; Chapter 11 (Ѻ)