The mind being, as I have declared, furnished with a great number of the simple ideas conveyed in by the senses, as they are found in exterior things, or by reflection on its own operations, take notice, also, that a certain number of these simple ideas go constantly together... which, by inadvertency, we apt afterward to talk of and condier as one simple idea.
John LockeMathematical proofs, like diamonds, are hard and clear, and will be touched with nothing but strict reasoning.
John LockeWe are born with faculties and powers capable almost of anything, such at least as would carry us farther than can easily be imagined: but it is only the exercise of those powers, which gives us ability and skill in any thing, and leads us towards perfection.
John LockeBrutes abstract not. -- If it may be doubted, whether beasts compound and enlarge their ideas, that way, to any degree; this, I think, I may be positive in, that the power of abstracting is not at all in them; and that the having of general ideas is that which puts a perfect distinction betwixt man and brutes, and is an excellency which the faculties of brutes do by no means attain to.
John Locke