For example Voltaire who said:
Their round eyes, their flattened nose, their lips which are always large, their differently shaped ears, the wool of their head, that very measure of their intelligence, place prodigious differences between them and the other species of men.
And they are not men, except in their stature, with the faculty of speech and thought at a degree far distant to ours. Such are the ones that I have seen and examined.
And one could say that if their intelligence is not of another species than ours, then it is greatly inferior. They are not capable of paying much attention; they mingle very little, and they do not appear to be made either for the advantages or the abuses of our philosophy.
And it is a big question whether among them they are descendants of monkeys, or if monkeys come from them. Our wise men have said that man is the image of God: behold a pleasant image of the eternal Being with a flat black nose, with little or no intelligence! A time will come, without a doubt, when these animals will know how to cultivate the earth well, to embellish it with houses and gardens, and to know the routes of the stars. Time is a must, for everything.
David Hume who said:
I am apt to suspect the N****s, and in general all other species of men, to be naturally inferior to the whites. There never was any civilized nation of any other complexion than white, nor even any individual eminent in action or speculation. No ingenious manufactures among them, no arts, no sciences... Such a uniform and constant difference could not happen, in so many countries and ages, if nature had not made an original distinction between these breeds of men
Emmanuel Kant, another philosopher had this to say:
The N****s of Africa have not received any intelligence from Nature that rises above foolishness. Mr. Hume challenges anyone to suggest even one example of a n**** who has displayed any talent. As he himself verifies, among the hundreds of thousands of blacks who have wandered far away from their homelands, even though many of them have been liberated, not one exists who has succeeded in anything great, either in the arts or the sciences or in any other noteworthy thing. On the contrary, among the whites, people continuously rise above the low point that they were and they evolve through their superior qualifications, attaining worldly fame. The difference therefore between the two races is an essential one: It appears to be equally big, both with regard to the capabilities of the mind, as well as to the color.
Some scholars even propose that modern European racism has its roots in the "Enlightenment" movement.