We have no other notion of cause and effect, but that of certain objects, which have always conjoin'd together, and which in all past instances have been found inseparable. We cannot penetrate into the reason of the conjunction. We only observe the thing itself, and always find that from the constant conjunction the objects acquire an union in the imagination.

All the sciences have a relation, greater or less, to human nature; and...however wide any of them may seem to run from it, they still return back by one passage or another. Even Mathematics, Natural Philosophy, and Natural Religion, are in some measure dependent on the science of MAN; since they lie under the cognizance of men, and are judged of by their powers and faculties.

A propensity to hope and joy is real riches; one to fear and sorrow real poverty.

Avarice, or the desire of gain, is a universal passion which operates at all times, at all places, and upon all persons.

In a vain man, the smallest spark may kindle into the greatest flame, because the materials are always prepared for it.

That the corruption of the best thing produces the worst, is grown into a maxim, and is commonly proved, among other instances, by the pernicious effects of superstition and enthusiasm, the corruptions of true religion.

From causes which appear similar, we expect similar effects. This is the sum total of all our experimental conclusions.