I make this chief distinction between religion and superstition, that the latter is founded on ignorance, the former on knowledge.

Anyone who seeks for the true causes of miracles, and strives to understand natural phenomena as an intelligent being, and not to gaze at them like a fool, is set down and denounced as an impious heretic.

God is not He who is, but That which is.

Except God no substance can be granted or conceived. .. Everything, I say, is in God, and all things which are made, are made by the laws of the infinite nature of God, and necessarily follows from the necessity of his essence.

So long as a man imagines that he cannot do this or that, so long as he is determined not to do it; and consequently so long as it is impossible to him that he should do it.

The endeavor to understand is the first and only basis of virtue.

The greater emotion with which we conceive a loved object to be affected toward us, the greater will be our complacency.