Pierre-Joseph Proudhon, Justice in the Revolution and in the Church, Volume I, "Program," section IV.
IV.-- The origin of ideas.
Here is the great temptation, I should say the great conspiracy of the philosophers; here is also their chastisement.
This principle so luminous, so simple, that in order to know the reason of things, it is necessary to have seen them, has not always been (can you believe it?) accepted in philosophy. Without speaking of those, in so great a number, aspired to sound the nature of things, one encounters profound geniuses who have asked if the human mind, so subtle and so vast, could not, by a concentrated meditation on itself; come to that intelligence of the reason of things, which is only, after all, the intelligence of the laws of the mind; if the man who thinks had such a need, in order to learn, to consult a nature which  does not think; if a soul created in the image of God, the sovereign organizer, did not possess, by virtue of its divine origin, and prior to its communication with the world, the ideas of things, and if it truly needed the control of phenomena in order to recognize ideas, that is, eternal exemplars. I think, thus I know, cogito, ergo cognosco such is the principle of these arch-spiritualist philosophers. Never has a brain which came from the ranks of the people conceived of a chimera like that. Some, interpreting in their own way the hyper-physical dogma of creation, go so far as to pretend that external realities are products of pure thought, and the world an expression of mind, so that it would be enough to have the full possession of the Idea, innate it our soul, but more or less obscured, in order, without further information, to possess the reason and grasp the very nature of the universe!
That manner of philosophizing, which would dispense with all observation and experience, if it had been justified by the least success, would be, we must admit, very attractive and could not be more convenient. The philosopher would no longer be that labored explorer, winning the bread of his soul by the sweat of his brow, always exposed to error by the omission of the least detail, reaching only a limited comprehension, obtaining often, instead of certainty, only probabilities, and sometimes ending in doubt, after having lived through an affliction of mind. He would be a clairvoyant, a thaumaturge, a rival to the Divinity, directing thought as a sovereign, to say nothing of creative power, and reading fluently the mysteries of Heaven, Earth and Humanity, at home with the divine thought. Ambition, as one sees, is never lacking among the philosophers.
Where does this titanic presumption come from?
From the start we have sensed, in a confused manner, what philosophical observation later clarified, that, in the formation of ideas, the perception of phenomena does not render reason by itself; that the understanding, by the constitution which is proper to it, plays a role; that the soul is not exclusively passive in its conceptions, but that in receiving the images or impressions from outside it,  it reacts to them and derives ideas from them; so that, for half if not for all, the passage of ideas, or the discovery of the truth in things, pertains to the mind.
Thus there was, one recognized, in the soul, like the molds of ideas, archetypal ideas, prior to all observation of phenomena: what were these ideas? Can we recognize them, among the multitude of those, more or less empirical, that the understanding strikes on its press? How to distinguish the patrimony of the mind from its acquisitions? If something in knowledge properly belongs to it, then why no everything? Wouldn't we be in the right to suppose that if the mind, possessing the innate principles of things, advanced in science only with the aid of arduous observation, that was the effect of the heterogeneous union of the soul and the body, a union in which the ethereal substance, offended by the matter, had lost the greatest part of its science and of its insight, retaining only a memory of the fundamental principles which formed its framework property?... Others attributed the darkening of the intelligence to original sin. Man, for having wanted to eat, against the express order of God, the fruit of science, would be, according to them, blinded. All the rest convince themselves that with a good mental discipline and the secours of the Spirit of light, one could restore the human soul to the enjoyment of its high and immortal prerogatives, make it produce science without any imbibition of experience, by the energy of his nature alone, and by virtue of the axiom already cited: I am the child of God, I think, therefore I know...
What was at the bottom of all that? A diabolical thought of domination: for one must not be mistaken, privilege of knowledge and pride of genius are the most implacable enemies of equality. Now one thing is known: human science is not enriched by the slightest scrap of a fact or idea by this exclusively pneumatic practice. Nothing has served: neither metaphysics nor dialectics, nor the theory of the absolute, nor revelation, nor possession, nor ecstasy, nor magnetism, nor magic, nor théurgie, nor catalepsy, nor ventriloquy, nor the philosopher's stone, nor table-turning. All that we know, we have  invariably learned, and the mystics, the illuminati, the somnambulists, even the spirits which which they speak, have learned in their turn by the known means, that is, observation, experience, reflection, calculation, analysis and synthesis: God, doubtless, jealous of his work, wanting to maintain the decree that he had entered, namely, that we would see nothing with the eyes of the mind except by the intermediary of the eyes of the body, and that all that we claim to perceive by other means would be an error and a mystification of the devil. There is no occult science, no transcendent philosophy, no privileged souls, no divinatory geniuses, no mediums between infinite wisdom and the common sense of mortals. Sorcery and magic, once pursued by parliaments, are dispelled by the flame of experimental philosophy; the science of the heavens had only begun to exist on the day when the Copernicuses, the Galileos and the Newtons bit an eternal adieu to astrology. The metaphysics of the ideal taught nothing to Fichte, Schelling and Hegel: when these men, whose philosophy is rightly honored, imagined they had deduced a priori, they had only, without knowing it, synthesized experience. By philosophizing more highly than their predecessors, they have enlarged the scope of science: the absolute, by itself, has produced nothing; translated into correctional policy, it has been jeered at as a con. In moral philosophy, mysticism, quietism and asceticism have led to the most disgusting turpitudes. Christ himself, Verb made flesh, had taught nothing new to the conscience; and the entirety of theology, patiently studied, is found, in the last result, convicted by its own testimony as nothing other than a fantasmagoria of the human soul, of its operations and its powers, liberty, justice, love, science and progress.
Willy-nilly it is necessary to keep to the common method, to confess in our hearts and with our mouths the democracy of intelligence; and since it is a question in that moment of the origin and the formation of our ideas, to demand the reason of the ideas, like all the rest, by observation analysis.