Spinoza's a priori proof for the existence of God

Question

I am currently studying some aspects of Spinoza's philosophy, mainly in contrast to Kant. It seems to me that Spinoza is just the kind of "dogmatic metaphysician" Kant criticises. I know that Kant tried to "proof" God's existence in his pre-critical phase, but later changed his mind (I refrain from going into details). I therefore wanted to have a look at Spinoza's "proofs". The first one says:

In the first place, a priori thus: 1. Whatever we clearly and distinctly know to belong to the nature of a thing, we can also truly affirm of that thing. Now we can know clearly and distinctly that existence belongs to the nature of God; Therefore...

It seems to me that this is far from "a priori" as Kant defines it. Furthermore, it rather seems to be a tautology. Because to say that we know that God exists because we clearly and distinctly know what his nature is means the same thing as to already know that he does exist.

Are there any other ways to read this? Am I mistaken? I am not looking for affirmation but on the contrary for arguments against my maybe premature opinion.

Answer 1

The SEP has an article on these sorts of proofs. I think it's fair to say that even people who endorse some sort of ontological argument don't find Spinoza convincing, for the reason you say.

However, since you wanted criticism I will point out that any proof like this is a "tautology", so I don't really think that's a valid objection. The question is whether its premises seem more reasonable than its conclusion, and they don't appear to.

You might find Godel's formulation more convincing. He basically replaces the idea of "nature" with that of "essential properties," and brings in modal logic. (Note that he never published any of these proofs, so there are various forms of "Godel's argument" floating around, some more reasonable than others.)

Answer 2

Maybe this quote from A. J. Ayer in "Language, Truth and Logic" is helpful:

To say that a proposition is true a priori is to say that it is a tautology. And tautologies, though they may serve to guide us in our emprical search for knowledge, do not in themselves contain any information about any matter of fact.

Answer 3

I haven't read Spinoza, but from your quotation, he doesn't say that we know the nature of God, he only says we know that existence belongs to the nature of God, and that we can know this. How does he justify that can?

He goes on to say that we cannot have knowledge without God, that our own power of imagination does not suffice. I probably agree that Spinoza smuggles in God from the beginning, but what ought to be of interest is does he say anything that illuminates. Is his metaphysical scheme interesting or profound.

I get the impression that he says that reality is a manifestation of God. It appears to have similarities with Asharite Occasionalism. To call it not a proof, I think is to miss the point somewhat - the form of his argument is a tribute, in perhaps the same way Platos dialogues are a tribute to the dramatic arts.

It also seems a tad retrospective, and a bit indecent to ask Spinoza to conform to Kants usage of the term 'a priori' when he was writing before Kant. It looked to me that his 'a priori', is just a synonym for his very first words 'In the first place', except it isn't, according to Enc. Brit

"The first recorded occurrence of the phrases is in the writings of the 14th-century logician Albert of Saxony. Here, an argument a priori is said to be “from causes to the effect”...Similar definitions were given by many later philosophers down to and including G.W. Leibniz"