Essays on The Active Powers of the Human Mind an Inquiry into the Human Mind on the Principle of Common Sense Quotes

“There is a disposition in human nature to reduce things as few principles as possible; and this, without doubt, adds to the beauty of a system, if the principles are able to support what rests upon them. The mathematicians glory, very justly, in having raised so noble and magnificent a system of science, upon the foundation of a few axioms and definitions. This love of simplicity, and of reducing things to few principles, hath produced many a false system; but there never was any system in which it appears so remarkably as that of Des Cartes. His whole system concerning matter and spirit is built upon one axiom, expressed in one word, cogito. Upon the foundation of conscious thought, with ideas for his materials, he builds his system of the human understanding, and attempts to account for all its phenomena: and having, as he imagined, from his consciousness, proved the existence of matter; upon the existence of matter, and of a certain quantity of motion originally impressed upon it, he builds his system of the material world, and attempts to account for all its phenomena.”
― Thomas Reid, Essays on The Active Powers of the Human Mind an Inquiry into the Human Mind on the Principle of Common Sense

“To this [i.e., Hume's argument] I answer that if a man believed that in heat there was a will to melt ice, he would undoubtedly believe that there is in heat a real efficient power to produce that effect, though he were ignorant how or by what latent process the effect is produced. So, we knowing that certain effects depend on our will, impute to ourselves the power of producing them, though there may be some latent process between the volition and the production which we do not know. So a child may know that a bell is rung by pulling a certain peg, though he does not yet know how that operation is connected with the ringing of the bell, and when he can move that peg he has a perfect conviction that he has the power to ring the bell. Supposing we were unable to give any account how we first got the conception of power, this would be no good reason for denying that we have it. One might as well prove that he has no eyes in his head for this reason: that neither he nor any other person could tell how they came there.”
― Thomas Reid, Essays on The Active Powers of the Human Mind an Inquiry into the Human Mind on the Principle of Common Sense