Here I must not be mistaken, to think that every floating imagination in men's brains is presently of that sort of ideas I speak of.

It is not easy for the mind to put off those confused notions and prejudices it has imbibed from custom, inadvertency, and common conversation.

It requires pains and assiduity to examine its ideas, till it resolves them into those clear and distinct simple ones, out of which they are compounded; and to see which, amongst its simple ones, have or have not a NECESSARY connexion and dependence one upon another.

Till a man doth this in the primary and original notions of things, he builds upon floating and uncertain principles, and will often find himself at a loss..