“Thenceforth they thought that, rationally concluded, doubt could become an instrument of knowledge.”

“Is there any knowledge in the world which is so certain that no reasonable man could doubt it?”

“Hegel’s lack of charity toward the instrument metaphor is not arbitrary. It represents his disenchantment with the assumption that knowledge is power and that method is the means to this end. … Descartes’ conception of method, like Bacon’s, is linked to this idea of knowledge as an instrument of power. … The same could be said of Locke. Hegel can rightly claim that the instrument metaphor pervades the epistemological tradition he is seeking to transcend.”

“Thought is not essential to existence nor its cause, but it is an instrument for becoming; I become what I see in myself. All that thought suggests to me, I can do; all that thought reveals in me, I can become. This should be man's unshakable faith in himself, because God dwells in him.”

“Kindness and friendliness become aspects of personalized service or of public relations of big firms, rationalized to further the sale of something. With anonymous insincerity, the Successful Person thus makes an instrument of his own appearance and personality.”

“Doubt is the offspring of knowledge: the savage never doubts at all.”

“Is there an observation which is not the instrument of thought?”

“The enlightenment of scientific and rational knowledge is skills expressing complex knowledge in an accessible and interesting way.”

“Knowledge of instrumentation should be acquired through experience. Instrumental composition should be conceived instrumentally, imagining and hearing a particular orchestra for each particular and diverse musical condition of the mind.”

“Knowledge begins with practice, and theoretical knowledge, which is acquired through practice, must then return to practice. The active function of knowledge manifests itself not only in the active leap from perceptual to rational knowledge, but - and this is more important - it must manifest itself in the leap from rational knowledge to revolutionary practice.”