[A] miracle is an event of which the causes cannot be explained by the natural reason through a reference to ascertained workings of nature; but since miracles were wrought according to the understanding of the masses, who are wholly ignorant of the workings of nature, it is certain that the ancients took for a miracle whatever they could not explain by the method adopted by the unlearned in such cases, namely, an appeal to the memory, a recalling of something similar, which is ordinarily regarded without wonder; for most people think they sufficiently understand a thing when they have ceased to wonder at it. The ancients, then, and indeed most men up to the present day, had no other criterion for a miracle; hence we cannot doubt that many things are narrated in Scripture as miracles of which the causes could easily be explained by reference to ascertained workings of nature. . . .

We cannot gain knowledge of the existence and providence of God by means of miracles, but we can far better infer them from the fixed and immutable order of nature. By miracle, I here mean an event which surpasses, or is thought to surpass, human comprehension: for in so far as it is supposed to destroy or interrupt the order of nature or her laws, it not only can give us no knowledge of God, but, contrariwise, takes away that which we naturally have, and makes us doubt God and everything else. . .

Scripture nowhere states the doctrine openly, but it can readily be inferred from several passages. Firstly, that in which Moses commands (Deut 8) that a false prophet should be put to death, even though he work miracles; "If there arise a prophet among you, and gives thee a sign or wonder, and the sign or wonder come to pass, saying, Let us go after other gods . . . thou shalt not hearken unto the voice of that prophet; for the Lord your God proves you, and that prophet shall be put to death." From this it clearly follows that miracles could be wrought even by false prophets; and that, unless men are honestly endowed with the true knowledge and love of God, they may be as easily led by miracles to follow false gods as to follow the true God; for these words are added: "For the Lord your God tempts you, that He may know whether you love Him with all your heart and with all your mind."

Further, the Israelites from all their miracles, were unable to form a sound conception of God as their experience testified: for when they had persuaded themselves that Moses had departed from among them, they petitioned Aaron to give them visible gods; and the idea of God they had formed as the result of all their miracles was — a calf!

…Nearly all the prophets found it very hard to reconcile the order of nature and human affairs with the conception they had formed of God's providence, whereas philosophers who endeavor to understand things by clear conceptions of them, rather than by miracles, have always found the task extremely easy — at least, such of them as place true happiness solely in virtue and peace of mind, and who aim at obeying nature, rather than being obeyed by her. Such persons rest assured that God directs nature according to the requirements of universal laws, not according to the requirements of the particular laws of human nature, and that, therefore, God's scheme comprehends, not only the human race, but the whole of nature.

From: Spinoza, Baruch. A Theologico-Political Treatise. R. H., Elwis trans. Copyright © 1951 Dover Publications, Inc., pp. 84-88.