"There is nothing in itself valuable or despicable, desirable or hateful, but as it acquires these attributes from the mind of the person who surveys it."

"Much human thought... is based on “a reasoning that is not in itself different from, nor founded on different principles, from that which appears” in animals."

"There is nothing in the mind of man that is not first in the senses, or in the operations of the mind itself."

"All belief of matter of fact or real existence is derived merely from some object present to the memory or senses, and a customary conjunction betwixt that and some other object."

"The fact is, that the greatest part of our reasonings, concerning matters of fact, are founded on the relation of cause and effect."