Heresy is a word which, when it is used without passion, signifies a private opinion. So the different sects of the old philosophers, Academians, Peripatetics, Epicureans, Stoics, &c., were called heresies.
Thomas HobbesBy this we may understand, there be two sorts of knowledge, whereof the one is nothing else but sense, or knowledge original (as I have said at the beginning of the second chapter), and remembrance of the same; the other is called science or knowledge of the truth of propositions, and how things are called, and is derived from understanding.
Thomas Hobbes