Della Rocca’s only valid case in point is the question “in virtue of what is ‘causa sui’ conceived as existing?” and, to that question, he can answer (if he can) by denying the validity of the question: causa sui, he will say, “is conceived to exist because it is what it is.” Only in the latter case may the PSR’s “invirtue-of-what” question be a bad question, reducible to a genuine misunderstanding.
But, in this light, it turns out that rationalism ultimately assumes the validity of the traditional ontological argument. The question in virtue of what substance is conceived to exist can be dismissed as a mere misunderstanding of the concept only if existence is a predicate, participating in substance’s essence. What needs to be underlined is that at stake is not merely a rationalist argument concerning the theological question of God’s existence. At stake is the viability of the rationalist position itself: Without the ontological argument, the edifice of conceivability and of the PSR falls apart.--Boehm, Kant's Critique of Spinoza, (160)
First a paragraph of (contextual) stage-setting, then I get to philosophy. The main interpretive claim of Omri Boehm's Kant's Critique of Spinoza, which is full of wonderful arguments and insightful unterpretations, is: that (a) in his pre-critical period, Kant isn't just familiar with Spinoza, but that he is a Spinozist (especially in the Beweisgrund); (b) and that in Kant's critical period Spinoza (and the threat of Spinozism) isn't just a central interlocuter (as a close analysis of the antinomies reveals), but that Kant is a regulative Spinozist. On (a) Boehm's argument nicely converges with my own claims about the pre-critical Kant (especially the Natural History of the Heavens). Our entirely independent arguments offer mutual support. (Isn't that peachy.) I just want to make two qualifications: (i) if Boehm had engaged more thoroughly with Ursula Goldenbaum's work (on Mendelssohn, and her work on historiography) he could have availed himself to more evidence and usefully complicated his story; (ii) Boehm has a tendency to treat the pre-critical Kant as a stable position rather as, itself, working through, and debating with, many interlocutors (I recommend this piece by Massimi for some of Kant's range). On (b) I leave it to Kant specialists to debate Boehm, although it is worth noting that Boehm's argument also allows -- with self-conscious nods to Jonathan Israel's work [but for reservations see here]-- us to put Kant into a wider eighteenth century context (still surprisingly rare in Kant scholarship).
The philosophical excitement of Boehm's book is to be found -- by way of treating Kant as critically engaging with Spinoza -- in the ways the ontological argument and the Principle of Sufficient Reason (PSR) mutually illuminate each other and, each in turn, debates over, modality, Causa Sui and, ultimately, the status of fatalism and (ahhh) nihilism. This is not just a matter of historical curiosity. Now that species of dogmatic (the technical term is 'knee jerk') metaphysics are back in fashion, including robust defenses of monism and the PSR, the question of nihilism and fatalism may well return as well (at some point). My plan is to engage with some of these rich issues in the course of a number of posts (and itself part of the series on the PSR that I started in context of Garber/Della Rocca debate).
Today, I focus on the “in virtue of what is ‘causa sui’ conceived as existing?” question (see the quote at the top of the post). This matters for the larger debate because if there is a decent Spinozistic answer to that question than transcendental realism is still in the game. My unargued for assumption here is that because Boehm accepts Della Rocca's conceivability focused interpretation of the PSR (seeLærke for reservations), he (Boehm) misses alternative ways to explore the issue.
I start with a low-level move. Boehm writes:
In Kant, naturalistic causality is understood as mechanical, or efficient causality. We naturalistically understand an event if and only if we see how it necessarily follows from another event that precedes it. Arguably, Spinoza favors a similar conception. A thing, A, is said to be the cause of another, B, if B necessarily follows from A (e.g., E Ip16c1; Ip25; II p5). Of course, a mechanistic conception is the hallmark of seventeenth-century scientific naturalism, of which Spinoza is supposed to be a champion. Now if one clings to this efficient naturalistic conception, the notion of a “self-caused entity” is identical to a notion of an entity that is “not caused at all.” For the causal conception that’s assumed in the notion of a self caused entity is entirely different from—in fact, it excludes—the naturalistic-efficient conception.
I doubt Boehm gets Kant's account of causation right in the first sentence (without, at least, mentioning the role of laws). But let's stipulate he does--he is certainly expressing a Kantian prejudice. (It is odd that after claiming that "the human intellect genuinely grasps how one thing can cause another," (143) there is no mention of Locke and Hume, who undermine the intelligibility and appeal of precisely this mechanical conception.) But in Spinoza (and arguably in Locke) the model form of causation is the way in which a (hidden) essence produces regular or (all things being equal) exception-less, (visible) effects. That is, in fact, the natural reading, too, of E1p16C1 (and E1p25 & E2p5, although the latter proposition is not explicit either way).* I often warn folk not to read Spinoza as a fellow traveler of the mechanical philosophy or even the scientific revolution (see here). This is not to deny that Spinoza also recognizes the mode-on-mode (billiard-ball) model of efficient causation (E1p28), but it is derivative from the exemplary model (and also has lower epistemic status).
Boehm might respond, gracefully, fair enough, Schliesser, but so much the worse for Spinoza; 'esssence --> effect' is a remnant of a discarded Aristotelian science. But that would be too hasty here. For, first, Spinoza does not rely on final causes/teleology (in this context). Second, Spinoza's 'essence --> effect' is, in part, modeled on (as he himself says in the Appendix 1 to Ethics 1) a formal cause explanation once common in geometry. And we can understand causa sui in such terms. (See this seminal article by Huebner; and anticipations in Viljanen and Schliesser.) Moreover, the way we understand such a hidden essence can be made compatible with both (the role of laws) in early modern science (and, in the hands of Joe LaPorte, modern science). [There is also historical irony that Boehm's Kantian rejection of causa sui echoes the Scholastic rejection of causa sui when they encountered it in Descartes (and Spinoza).]
Even so, it looks like Boehm still may say that even if the causa sui** can be made respectable, we still have to make existence a first order predicate to make the position cogent. Let's accept that (it is, after all, the natural reading of E1D1). Some other time I'll explore if it follows that in Spinoza we should treat existence as an attribute (as I used to think), or, (as I now think) that (no less dazzlingly) existence just is truth (recall this post). Rather, here I want to close with a Spinozistic, alternative (due to Clarke! [recall]) answer to the “in virtue of what is ‘causa sui’ conceived as existing?” question. For, from the vantage point of the (Spinozistic) PSR, the only proper answer is 'necessity.' Necessity both legitimately ends an explanatory regress and is a proper primitive ground that avoids opening the door-too-easily-to-idealism (as Della Rocca's version of the PSR does) and building a kind of harmony-between-mind-and-world-view (the optimistic side of rationalism) into Spinozism from the start. For, once one shows that something is necessary, there is no need for a further question (obviously, this can be easily abused in human affairs as a species of ideology, so one should be suspicious of instances of this strategy).
According to Clarke necessity is the “formal cause” of God (and the grounds of all existence--see [THE ANSWER TO A SIXTH LETTER, BEING PART OF A LETTER WRITTEN TO ANOTHER GENTLEMAN, ). As he explains earlier in correspondence with Butler:
Necessity absolute and antecedent in the order of nature to the existence of any subject has nothing to limit it; but if it operates at all (as must needs do), it must operate (if I may so speak) everywhere and at all times alike…. (Clarke’s “Answer to Butler’s Third Letter,” Dec 10, 1713)
To put Clarke’s point informally: absolute necessity has the same impact everywhere and all times and should have the same consequence everywhere and all the time. So, if such necessity operates in some respect, Y, then we ought to expect Y to be homogeneous in relevant ways. (And if the most fundamental form of necessity operates in all (possible) respects, then we ought to expect general homogeneity.) But here what matters is that such absolute necessity has "nothing to limit it." The operation of it (such necessity) is, thus, the right kind of 'cause' or explanatory ground to help account for the existence of infinite entities (substance, space, time), including the right sort of totum analyticum. (This is why Boehm is right to argue that when one tries to be consistent, the PSR, some versions of the ontological argument, and necessaritarianism all entail and support each other.) So, the cause of substance, understood as natura naturans, is, itself, 'absolute necessity --> absolute existence.'
Obviously, Clarke's view of modality is metaphysical and without further articulation and formalization obscure. (And part of the problem is, that modern formal approaches of modality are, to the best of my knowledge developed in ways that do little justice to the Spinozistic intuitions behind this notion of necessity.)
I close by reminding the reader that I have not claimed that this answer to the “in virtue of what is ‘causa sui’ conceived as existing?” question refutes Boehm. All I have claimed above is that this approach is a genuine alternative to Della Rocca's approach which frames Boehn's way of exploring the debate between Kant and Spinoza. But I also submit that this helps explain why one species of the ontological version of the PSR ("for every infinite entity that exists, there is a reason why it exists") may not be a transcendental illusion after all. (I am here inspired by Daniel Schneider's work on the ontological argument.) Again, this does not settle the debate. But, rather, it is to reinforce Boehm's claim that the proper, ultimate locus of the debate between the Kantian and the Spinozist is on the plane of modality/necessity, and especially how these are related to our moral and epistemic convictions (183, which is -- to echo Boehm's inroduction -- just to say that Athens and Jerusalem are live options); or why analytical existentialism is foundational philosophy. Let me stop here, for now.
PS. As I have argued, Clarke's position was not obscure historically, but is also clearly visible in Newton's General Scholium. This is why I say above that Boehm's book opens the door to re-opening Kant to eighteenth century philosophy.
*The three propositions that Boehm cites all talk of God as 'efficient cause;' but Boehm fails to explore how God's efficiency works.
**A sniper-of-Schliesser may suggest that I am inconsistent in not translating causa sui, but I do so here because I am discussing Boehm's views.