Parmenides and Spinoza

Interview by Richard Marshall

'I’m keenly aware of the possibility of the Parmenidean (e.g., me!) undermining their own position. After all, explanation itself seems to be relational; things are explained (often at any rate) in terms of other things. I don’t shy away from this apparent or even real self-undermining. For me, it’s a feature not a bug. And I embrace this self-undermining, in much the same way that Parmenides may have (see especially Owen’s reading of Parmenides), as Wittgenstein does at the end of the Tractatus, as Bradley does, and as my skeptical hero, Sextus Empiricus, does. In this way, I offer—paradoxically perhaps—a relational metaphysical challenge to relational metaphysics itself.'

'Intuitions and common sense are not, I claim, a good basis on which to reach philosophical conclusions. What then should we do? My suggestion is to be alive to skepticism, to turn to the history of philosophy, especially philosophy before what I call the iron curtain of intuitions descended on philosophy, and to be guided by the Priciple of Sufficient Reason.'

'I interpret Spinoza as rejecting teleology outright and even as rejecting as illusory apparent teleological behavior in humans and other animals. (Here I am in broad agreement with the readings of John Carriero, Karolina Hübner, and others). Nothing acts for the sake of an end, and the thought that we and perhaps some other things do is just an illusion.'

'Spinoza is a naturalist in the sense that everything plays by the same rules or laws.'

'Spinoza and Leibniz are both panpsychists—everything is minded in some way—they are also both panvitalists, I would say, everything is alive.'

'Spinoza is a shining example of a philosopher who has a naturalist world view that taps into (and thus naturalizes) religious ways of thinking.'

Michael Della Rocca is interested in the History of Modern Philosophy, Metaphysics, Philosophy of Mind and is a leading authority on Spinoza. Here he discusses whether metaphysics is useful, the Principle of Identicals, the monism of Parmenides, Parmenidean ascent, its impact on theories of knowledge, whether Quine and Davidson were Parmenidean, how Parmenides threatens the struts of analytic philosophy, the 'taming strategy', undermining it, intuitions and common sense, brute facts, Spinoza and the Principle of Sufficient Reason, Spinoza's rationalism, his naturalism, Spinoza and Leibniz, parallelism, Spinoza and Nietzsche, and why there's a point in studying Spinoza.

3:16: What made you become a philosopher?

Michael Della Rocca: My answer to the question of what made me a philosopher is really the same short answer that anyone can give: as Spinoza would say, Deus sive Natura (God or Nature).

3:16: Some people – some philosophers included – don’t regard metaphysical questions as being useful. In your discussions regarding the Principle of Identicals you defend a load of ‘why-questions’ that typify the methodology of some metaphysics. So can you sketch for us how you defend the why questions – why aren’t they irrelevant, nonsensical and their illumination is merely illusory as some people think?

MDR: Before answering this question, I want to address the correct point you make in setting it up, viz. that some philosophers don’t regard metaphysical questions as useful. It may seem surprising for some people to hear me saying this, but in a significant sense I completely agree with that statement. I regard many metaphysical questions—questions which often have robust metaphysical presuppositions—as on the wrong track, as less than illuminating, or even as distorting. But I think that before reaching that negative assessment, we must earn the right to make it. To earn that right, in much of my recent and forthcoming work (particularly in the forthcoming book, The Parmenidean Ascent), I aim to play the metaphysical game and to show in detail where metaphysical questions go astray and how the methods that are often deployed to answer them are, in effect, bankrupt. But, again, to get to that point I play the metaphysical game and much of my work can be seen as tending to a rationalist metaphysical critique of not only metaphysics itself, but also of much of philosophy that is conducted according to methods prevalent in so-called analytical philosophy. So, although I am worried about metaphysics itself, I think that there’s a lot of metaphysical work to be done, insights to be gained, before this critique of metaphysics itself reaches its dénouement.

To get to the heart of your question: yes, in much of my work I discuss a principle of identicals. More specifically, You are right that, in doing so, I invoke a bunch of why-questions and offer answers to them.

There are many ways of seeing the defense of the PII as going—and I’ve advanced more than one in my work—but the key move is this: in virtue of what are A and B not identical? If one answers: “in virtue of being in different locations,” then the question just re-arises in a different form: in virtue of what are these locations not identical? If you say instead, “A has the property of being distinct from B, therefore A is distinct from B,” then you have succeeded perhaps in saying something true. But it is also, alas, trivial. So this response too goes no distance toward offering genuine illumination on the issue of what it is in virtue of what A and B are distinct.

I take such why-questions seriously—i.e. I think that they demand an answer, and I’m certainly not alone here. Such questions are for me a hallmark of rationalism. Rationalism can mean lots of different things to different people, but for me the Principle of Sufficient Reason (the PSR) is central to rationalism. The PSR is the principle according to which there are no brute facts that obtain or no things that exist without an explanation. That is, each thing or each fact has an explanation. The PSR is the guiding force of Leibniz’s and Spinoza’s work, and also of Parmenides’ and Bradley’s (and, I would say, Hegel’s too).

Understood in terms of the PSR, rationalism is completely compatible with empiricism, understood as a view which gives some kind of priority to the senses in our having or coming to have knowledge. Empiricists can—just as rationalists do—take explanatory demands seriously and empiricists can even, in principle, embrace the PSR. Even without insisting on the full-blown PSR, philosophers of all stripes can and do embrace explanatory demands in a given domain. One of my goals is to draw out or elicit these explanatory demands and to see how they can be seen as driving the views of various philosophers.

This is the case with my defense of the identity of indiscernibles. I begin with explanatory claims that very many philosophers embrace or seem to embrace—claims to the effect that such-and-such a situation is to be ruled out precisely because it would involve inexplicable facts. I then ratchet up the pressure by showing how this explanatory demand generates momentum to go further and, in this case, eventually generates pressure to accept the identity of indiscernibles and indeed the full-blown PSR.

What I am offering here is a kind of survey of philosophers that reveals that they accept explanatory demands in particular domains, and I point out that it seems right that they do accept these explanatory demands. I think that explanatory demands are the lifeblood of philosophy, and you don’t need me to say that they make sense and should be taken seriously. People already do take them seriously. After showing that certain explanatory demands are accepted, I then try to make life difficult for my interlocutors by showing how the explanatory demands that they already accept lead to surprising or even troubling consequences.

3:16: You’ve investigated the monism of Parmenides – you say it’s what you call a version of ‘strict monism’ – and you’ve also addressed the issue of whether we’re doing philosophy when we look at Parmenides. So first, what’s his monism about? What is meant by the idea of a Parmenidean ascent with regard to substance, action, knowledge and meaning?

MDR: Parmenides, as I interpret him, is a strict monist in the sense that he denies that there are any negations or distinctions whatsoever (i.e. one thing’s not being another). Indeed, for Parmenides, such distinctions, such negations, and any multiplicity are unintelligible—they cannot even be thought of. Parmenides puts this point by saying that non-being cannot be thought. I’m skating over a large territory here, and—significantly—also stepping on lots of toes in the scholarship on Parmenides much of which has lately had a tendency to read him as espousing a watered-down or much more limited or tamed version of monism. There are important exceptions, of course, including my former colleague, Barbara Sattler, who has a great book forthcoming, The Concept of Motion in Ancient Greek Thought, a book in which Parmenides and Zeno, who was inspired by Parmenides, are central characters. My strict monist reading of Parmenides is more in line with those of previous generations of commentators than with those of most commentators on Parmenides today. I should note, though, that the work of Alexander Mourelatos is also tremendously illuminating for me (despite the fact that Mourelatos does not adopt a strict monist reading).

On my interpretation, at the heart of this strict, radical monism in Parmenides is the PSR which, as I interpret Parmenides, is the driving force in his philosophy, a force leading him both to the view that there cannot be any distinctions and to the view that distinctions cannot even be thought.

Parmenides’ successors—notably Plato and Aristotle—were haunted by Parmenides’ vision, and they sought to make the world safe for distinctions and multiplicity. Whether they succeeded is another matter. My view is that this move in Parmenides from the PSR to a strong version of monism or a rejection of all distinctions and multiplicity is repeated time and time again in the history of philosophy. Attempts to avoid this result either by limiting the PSR or denying it outright fail. We see this pattern enacted by Spinoza and in the responses to Spinoza by Hume and Kant. We see this pattern also in Bradley and the reactions against him by Russell and Moore, those proponents of relations. There are other displays too of this kind of dynamic. And in each case, the PSR-fueled monism is resisted (successfully or not) by limiting or denying the PSR. With regard to the Bradley-Russell-Moore dance, we can see in this light that the unprincipled restriction of or denial of the PSR that we find in Russell and Moore is central to the origins of analytic philosophy; it is, in effect, the original sin of analytical philosophy.

I endorse Parmenideanism in my own voice for reasons stemming from the PSR, and I think that this rationalist approach can open us up to what I call Parmenidean Ascents in various domains including the areas you mention: substance, action, knowledge, and meaning. Thus, there are no differentiated substances or beings, actions, knowledges (instances of knowledge), or meanings. There is, one might say, being or substance, but not substances or beings; there is action, but no actions. For me, these terms (“substance”, “action”, “knowledge”, “meaning”) are not count nouns, but are something like mass terms.

The challenge in each of these cases is this: we ordinarily think of actions, etc. as differentiated, as relational, but for me there is no good way to make sense of such differentiation, such relations, and so—in order to save or redeem the concepts of substance, action, knowledge, and meaning—we have to ascend to an undifferentiated, non-relational version of these phenomena, if they are to be saved or redeemed at all. We take the reality that we were trying to capture in terms of differentiation and, instead, we capture it better by appealing to undifferentiated versions of these phenomena. In this way, my account is deeply skeptical, not in the tame sense of denying that we know that there are instances of these phenomena, but in the sense of denying that we have a coherent conception of these phenomena, at least of these phenomena as involving distinctions.

3:16: If the notion of Parmenidean ascent is right when applied to action, then what impact does it have on understanding freewill and moral philosophy generally?

MDR: These areas are to be totally reconceived. With the rejection of individuated action, most standard moral theories are undermined to the extent that such theories as consequentialism, deontological theories, and virtue ethical accounts focus on individuated actions or, at least, individuated agents. If these theories have such a focus—and it’s difficult to see how they don’t—then they trade in incoherent relational notions. For similar reasons, I think that the debate over compatibilism and incompatibilism with regard to the problem of free will presupposes individuated, differentiated actions. As such, this debate too is to be reconceived once we make the Parmenidean move of saying that all is action. I haven’t fully carried this out yet.

3:16: And what difference does it make in the domain of knowledge?

MDR: I think that leading theories of knowledge — both what I call “building block” views which try to explain states of knowledge in terms of other supposedly prior phenomena such as belief, truth, and justification and so-called “knowledge-first” views — fail to meet the demand for explanation or illumination of the notion of knowledge, a demand that proponents of such theories embrace in one way or another. I argue—here in the case of knowledge and similarly in the cases of being, action, and meaning—that there is a principled reason for the pervasive failure of these theories to meet the explanatory demand. The culprit here is the relationality involved in the ordinary conception of knowledge. This problem is brought to light by an updated form of Bradley’s regress argument concerning relations, an argument that I reconceive and defend from a host of ultimately ineffectual objections. As in the other cases, we must ascend to a non-differentiated version of knowledge. The notion of knowledge—as ordinarily conceived as a differentiated, relational state—is incoherent; it cannot be thought.

[Davidson and Quine]

3:16: Were Quine and Davidson Parmenidean in their approaches to meaning?

MDR: In an important sense, yes. Let me illustrate in the case of Quine. Quine was a closet rationalist in my sense, though of course he would never admit that, and he was also a, perhaps, unwitting Parmenidean. The Parmenideanism—the rejection of distinctions—comes out explicitly in the case of meaning. Quine famously rejects the analytic-synthetic distinction—a good move from a Parmenidean point of view which is inimical to distinctions as such. (And it’s also worth noting that Bradley gives his own rationalist argument for rejecting this distinction.) In rejecting the analytic-synthetic distinction, Quine rejects differentiated meanings: there are no differentiated nuggets of meaning or discrete chunks or atoms of meaning; rather, Quine says, in one of my favorite quotes from Quine expressing an almost outlandishly Parmenidean sentiment: “the unit of empirical significance is the whole of science” (p. 42 of “Two Dogmas”). Quine’s holism is so radical that, for him (or at least for the Quine of “Two Dogmas”), there are no discrete meanings, not even one meaning, there is just meaning, undifferentiated meaning. In this way the term “meaning” is treated by Quine—and he is explicit about this—as something like a mass term.

Why does Quine accept such Parmenideanism about meaning? His reason, I contend, is much the same as Parmenides’ (and Bradley’s) reason: the PSR. In fact, in one smoking gun passage—another of my favorite passages from Quine—he takes the holistic considerations behind his rejection of the analytic-synthetic distinction as turning on what he revealingly calls “the law of sufficient reason.” (He does this in his paper, “Carnap and Logical Truth”).

3:16: How does this monistic position dissolve the struts of analytic philosophy and help you to establish that investigating Parmenides is philosophy rather than just history of philosophy?

MDR: This PSR-driven rejection of distinctions and of relations threatens some of what I call the struts of analytical philosophy: the method of intuition, realism, and discreteness. “The method of intuition” is my catch-all term for the method whereby analytical philosophers (especially) consult a magical faculty of intuition or invoke common sense, however that much abused term is understood. (It’s important to note that the appeal to common sense and the appeal to intuition are not the same). Realism is a view according to which the world is in general not dependent on our ways of thinking about it. This is roughly what Ted Sider calls “knee-jerk realism.” Discreteness is the view that reality consists of loose and separate items. And the PSR-driven monism or Parmenideanism with regard to meaning also brings down the distinction between philosophy and the study of its history. The principled rejection of this distinction is one of the most important upshots of my work in this Parmenidean, rationalist vein.

3:16: If the notions of grounding and metaphysical explanations are incoherent, then don’t you undermine your earlier arguments establishing the Parmenidean ascent? Do we have to go back to a non-monistic view? Is this the issue that Wittgenstein tried to solve?

MDR: The challenge I raise to ordinary notions of substance, action, etc., applies also to the notion of metaphysical explanation itself. So, I’m keenly aware of the possibility of the Parmenidean (e.g., me!) undermining their own position. After all, explanation itself seems to be relational; things are explained (often at any rate) in terms of other things. I don’t shy away from this apparent or even real self-undermining. For me, it’s a feature not a bug. And I embrace this self-undermining, in much the same way that Parmenides may have (see especially Owen’s reading of Parmenides), as Wittgenstein does at the end of the Tractatus, as Bradley does, and as my skeptical hero, Sextus Empiricus, does. In this way, I offer—paradoxically perhaps—a relational metaphysical challenge to relational metaphysics itself.

3:16: What’s the taming strategy – you link it to philosophers such as Kant, Kit Fine, Jonathan Schaffer and Shamik Dasgupta – and why do you say it’s a strategy that needs taking down?

MDR: The taming strategy is a strategy of would-be friends of explanation who try to limit the scope of the PSR before it leads to its apparently terrible consequences. Such philosophers let the PSR-train leave the station, but then try to limit the PSR, to stop it in its tracks. You see this strategy especially in Kant—a big fan of the PSR, but of a version of the PSR with its wings clipped—as Omri Boehm (in his wonderful book, Kant’s Critique of Spinoza), Béatrice Longuenesse, and others have shown. This strategy of taming the PSR can also be seen as at work in much contemporary metaphysics, including work that I otherwise admire a great deal.

I think that this taming strategy should be rejected because it is inherently conservative and, in the end, unprincipled. The reliance on intuition and common sense is, in my view, a symptom of this conservatism. Even flexible methods such as a Rawlsian reflective equilibrium are guilty of this conservatism.

3:16: So how do you take it down? And why do philosophers resist your arguments and what does that tell us about the history of analytic philosophy and what philosophy owes to history?

MDR: I try to undermine the taming strategy by challenging the three struts: realism, the method of intuition, and discreteness. And I challenge these three struts by appealing to my Bradleyan, rationalist argument against relations. I also argue against the taming strategy by showing that in the end it undermines itself and that a commitment to a restricted, tamed form of the PSR leads inevitably to an unrestricted, untamed form of the PSR. So the taming strategy contradicts itself. Of course, I face the threat of self-undermining too, but I predict this threat and welcome it (in much the same way that on my reading Parmenides, Bradley, Wittgenstein, and Sextus do). And again this is because I am in the business of giving a relational metaphysical critique of relational metaphysics itself.

3:16: So can you summarise where we are – or should be – with regard to the use of intuition in philosophy? Are most of the leading contemporary philosophers making an error by using it?

MDR: Intuitions and common sense are not, I claim, a good basis on which to reach philosophical conclusions. What then should we do? My suggestion is to be alive to skepticism, to turn to the history of philosophy, especially philosophy before what I call the iron curtain of intuitions descended on philosophy, and to be guided by the PSR.

3:16: OK, so let's now turn to your other great interest, Spinoza. Your understanding of Spinoza is different from many others in that you say that he never reaches a point where the world is recalcitrant and facts become brute. Before saying what Spinoza thought of this can you sketch for us why thinkers of all stripes tend towards reaching a point where nothing more can be said, a point where they say, as Wittgenstein had it, ‘ My spade is turned.’

MDR: Different philosophers may have different reasons for being willing or even happy to embrace brute facts, but I think that often such willingness derives from a desire to avoid any kind of affront to so-called common sense and a tendency to give undue weight to an alleged faculty of intuition. (Again, the appeal to common sense and the appeal to intuition are not the same thing.) Ultimately, the fear of the PSR comes from a fear of giving up our ordinary, complacent attitudes of various kinds. And I think that Spinoza would see the resistance to the PSR in this way.

3:16: For you Spinoza kicks against this kind of thinking. He says literally everything has a sufficient reason explaining it. Can you say what this very strong version of the principle of sufficient reason (PSR) is for Spinoza, and why he holds it? Does this link with his idea of Geometry as a controlling image of his system building and understanding of necessities? How does Spinoza avoid vicious circularity in justifying the PSR and intelligibility?

MDR: Spinoza doesn’t actually use the term “Principle of Sufficient Reason” (or the equivalent in Latin). Leibniz and later philosophers have used this term. Spinoza’s classic statement of his version of something like the PSR is explicit in Ethics 1p11d2 (the second demonstration of proposition 11 of part 1 of the Ethics): “For each thing, there must be assigned a cause or reason, both for its existence and for its nonexistence.” One can see a commitment to the PSR as fairly explicit in the axioms of Part 1 as well. Excellent commentators such as Sam Newlands, Yitzhak Melamed, Martin Lin, and Don Garrett have done great work in locating something like the PSR in the axioms.

1p11d2 focuses on the existence of things: each thing that exists has a reason or cause. But I think that it can be shown that, for Spinoza, this thing-version of the PSR leads directly to versions of the PSR focused on facts or states of affairs: each fact that obtains has a reason or cause.

It is natural to see the PSR as bound up with Spinoza’s use of the geometrical method in the Ethics. However separate papers by Eric Schliesser and by Alison Peterman have recently called into doubt the view that geometrical thinking is central to his thought. Stephen Harrop is working on a dissertation which attempts to restore a reading of Spinoza as making important use geometrical thinking. I’m eager to see how this debate about the geometrical method plays out. But whatever the status of the geometrical method, the PSR is definitely central to Spinoza’s thought.

There is, though, the issue you raise about whether or how Spinoza justifies the PSR. Spinoza doesn’t offer a direct argument for the PSR, and it may be too fundamental a principle to receive a justification. But I would say that attempts to deny the PSR lapse into incoherence for reasons I alluded to earlier, and this way of challenging a denial of the PSR may be available to Spinoza.

3:16: Does Spinoza’s rationality mean that he denies a finite, subjective perspective that seems to be at the heart of what it is to be a human being? Does rationalism mean that everything has a reason and therefore a teleology – and don’t many philosophers and scientists just think this is false – and a bit crazy!? Why do you defend rationalism and Spinoza?

MDR: I’ll take these questions in order.

Spinoza’s rationalism has often been thought to lead to the denial not only of finite, subjective perspectives, but also of the existence finite things themselves. This is one of the liveliest topics in recent Spinoza scholarship. I take very seriously the view that, for Spinoza, finite perspectives and finite things themselves are not real and do not exist. (Notice that I do not draw here a distinction between reality and existence.) The only truly existing thing, for Spinoza, is substance or God. This is, roughly, Hegel’s interpretation of Spinoza, and I think that Hegel is right, at least insofar as there is a strand in Spinoza’s thinking according to which finite things are not real and the reality that we mistakenly attribute to finite things is better captured or better expressed by appealing simply to the essence of God.

This is a broadly Parmenidean interpretation of Spinoza, and it’s something that Spinoza is led to—again, at least in one strand of his thinking—by the PSR. Or so I argue. There is here too a lively debate ongoing in the literature on this point. In addition to Melamed’s great work in criticism of an Eleatic reading of Spinoza, another work defending the finite in Spinoza and especially defending the existence of the subjective in Spinoza is Ursula Renz’s. Her wonderful book on experience and the subjective in Spinoza was recently translated into English and is a great challenge to a reading of Spinoza as denying the subjective and the reality of the finite. Renz’s book is The Explainability of Experience: Realism and Subjectivity in Spinoza’s Theory of the Human Mind (originally: Die Erklärbarkeit von Erfahrung: Realismus und Subjektivität in Spinozas Theorie des menschlichen Geistes). Noa Shein has also done important work in defending the reality of the finite in Spinoza.

Rationalism as I understand it—i.e. as a commitment to the PSR—does not mean that things in general have a purpose or act for the sake of an end or engage in teleological behavior. I interpret Spinoza as rejecting teleology outright and even as rejecting as illusory apparent teleological behavior in humans and other animals. (Here I am in broad agreement with the readings of John Carriero, Karolina Hübner, and others). Nothing acts for the sake of an end, and the thought that we and perhaps some other things do is just an illusion. All things have reasons or causes, but these reasons or causes are not final causes or teleological reasons. For Spinoza, the mistaken belief that we act for the sake of an end is bound up with what he sees as the illusion that we act from freedom of the will.

Why do I defend rationalism and Spinoza? My defense of rationalism is discussed earlier in this interview. My primary aim in studying Spinoza is to bring his thought to life—to understand the various themes that are interwoven in and that actuate his philosophy. I also find very much of what Spinoza says congenial, especially insofar as his system is one of the most thorough engagements with the PSR in the history of philosophy. This is not to say that I agree with everything Spinoza says (I don’t) or that I see the PSR as the key to understanding everything in Spinoza’s philosophy.

3:16: You make his commitment to the Principle of Sufficient Reason the basis of his naturalism. So can you say why PSR is the key to his naturalism – and what other kinds of naturalism does this contrast with? Usually when philosophers talk about naturalism they exclude God, but God is at the dead centre of Spinoza’s system isn’t it. So what does Spinoza say about religion? Why does Spinoza on the one hand have a reputation for being a naturalist and also a religious heretic and yet still have God? Was he some sort of Pantheist, a Deist or was he deep down an atheist? Or was he a radical Jewish theologian?

MDR: For me, Spinoza is a naturalist in the sense that everything plays by the same rules or laws. There are no exceptions to these rules and there are no special beings that stand apart from nature instead of being a part of nature or, better, an expression of nature. Spinoza gives voice to his naturalism in the preface to Part 3 of the Ethics and elsewhere.

In this vein, Spinoza railed against Descartes in particular for treating the minds of human beings as not governed by the same principles that are at work in the extended or physical realm. Descartes sees these minds as literally supernatural. Spinoza also sees God as fully natural too; indeed, God just is nature and nature just is God, for Spinoza. God—a natural being or nature itself—makes possible all other beings, to the extent, of course, that there are any other beings Recall that the reality of finite beings in particular is better captured by appeal to the essence of God itself and of nature itself.

Spinoza is certainly not a deist—a deist would see God as in some way detached from the world God creates; such a God walks away from the world. Spinoza’s God doesn’t walk away from the world.

I think that Spinoza is also not an atheist: he has a non-traditional conception of God—as extended and not just as thinking, as not a person, as not acting purposefully, as not acting out of a special concern for human beings—but it is a conception of God as a self-conceived, self-explanatory, all knowing being. These features are in keeping with some traditional features ascribed to God (even if Spinoza is out keeping with the traditional conception in other respects). Further, for Spinoza God is worthy of love, supremely perfect and powerful and thus good and virtuous, in Spinoza’s sense of these terms. Spinoza equates goodness and virtue with power.

3:16: His contemporary Leibniz also held to something close to the PSR, didn’t he, and the two met. How does Spinoza’s approach to the PSR compare to Leibniz’s approach? Did they learn anything from each other? Both might hold a version of panpsychism, for example, although surely they conflict over why: Spinoza would like the idea of each of Leibniz’s monads having some sort minds would he?

MDR: Yes, as I mentioned, both Leibniz and Spinoza endorse the PSR and the PSR is equally important in both of their systems. But the versions of the PSR they endorse are importantly different. For both, everything has an explanation; but for Leibniz the explanations that he allows and requires are (at some level) teleological explanations, and for Spinoza they are not. And in his application of the PSR, Leibniz appeals to the will (as distinct from the intellect) as the key explanatory element. But Spinoza has no such appeal to a distinct will in his uses of the PSR or in general. For him, intellect and will are identical. This rationalist insight is getting more and more uptake in contemporary philosophy of mind. Will Ratoff is doing exciting work pursuing this kind of rationalist project in the context of contemporary cognitive science, philosophy of action, and philosophy of mind.

Spinoza and Leibniz not only corresponded a bit, but they also met (in 1676), a few months before Spinoza died. There is evidence that Spinoza did not trust Leibniz (Spinoza’s motto is, after all, caute– carefully). Leibniz did engage deeply with Spinoza’s thought, especially in the 1670’s—just before and after their meeting. But, despite some occasional flirtations with Spinozistic monism and necessitarianism (the thesis that all truths are necessary), Leibniz stepped away from the precipice of Spinozism and, for most of his career, wrote pretty disparagingly of Spinoza’s philosophy. Leibniz was, I think, struggling with the power of Spinoza’s monism and sought to avoid Spinoza’s denial of God as creator of a world distinct from God, Spinoza’s denial of the freedom of the will, and Spinoza’s denial of contingency. But there is much in common, too, between them, besides some form or other of the PSR. In particular, as you mention, Spinoza and Leibniz are both panpsychists—everything is minded in some way—they are also both panvitalists, I would say, everything is alive. All finite things are mind-like, but for Spinoza finite minds are not substances, not things in their own right, whereas for Leibniz they are. This commitment to finite substances is, for Leibniz, important in preserving what is, for him, a meaningful kind of human freedom.

3:16: How does Spinoza avoid being an idealist? Does the fact that he thinks the conceptual outstrips the mental help him achieve this?

MDR: He doesn’t avoid being an idealist. In one important sense of idealism—the sense according to which the existence of anything depends on its being conceived or being thought of by a thinking thing—Spinoza is an idealist. His commitment to a version of the PSR pretty much guarantees that he is this kind of idealist. I will stress the connection between Spinoza and idealism in the second edition of my book, Spinoza, which I am preparing now.

3:16: Why does Spinoza hold the view of parallelism, that the order and connection of ideas is the same as the order and connection of things, and what has it got to do with representation?

MDR: This parallelism follows from his view that effects are conceived or understood or explained through their causes. So for each effect there must be a concept or idea or representation of it, and this concept or idea or representation must be caused or explained by the concept or idea or representation of the cause of that effect.

3:16: He was recognised by Nietzsche as being a precursor to many of Nietzsche’s thoughts, for example, they both denied free will didn’t they - but was there a big divergence between Spinoza’s notion of conatus and Nietzsche’s will to power? Can you say something about this and how you see the relationship between these two thinkers.

MDR: Yes, Spinoza and Nietzsche both deny the freedom of the will, as Nietzsche recognized. There are many other affinities between the two: both rejected any distinction between doer and deed and between will and intellect; both rejected any source of value of a thing that is external to that thing. I’m not sure that there is any significant conflict between Spinoza’s conatus and Nietzsche’s will to power. Where there might be a fundamental difference is with regard to Nietzsche’s rejection of a notion of absolute truth.

3:16: Does Spinoza’s political thinking support authoritarian government?

MDR: Spinoza allows for and requires a good deal of freedom of thought and even of speech. But action, more generally, is much more constrained. And in a Spinozistic state, the sovereign has control over a state religion.

3:16: You commented at the beginning of your 2008 book that there was a time when modern philosophers couldn’t see the point of studying Spinoza. How would you summarise his importance for contemporary philosophers today and how would you summarise his achievements? Was he the last of the medieval or the first of the moderns? (Or neither!)

MDR: Spinoza is a shining example of a philosopher who has a naturalist world view that taps into (and thus naturalizes) religious ways of thinking. All of this is made possible by the PSR. And instead of seeing Spinoza as the last of the medievals or the first of the moderns, I prefer to see him as a distinguished member of a distinguished chain of philosophers who have availed themselves of what can be seen as natural kind in philosophy: the connection between the PSR and a radical form of monism.

3:16: And finally, for the curious readers here at 3:16, are there books you can recommend other than your own that will take us further into your philosophical world?

MDR: Besides works by Parmenides, Spinoza, and Bradley, I would suggest in no particular order:

Alexander P. D. Mourelatos, The Route of Parmenides. A fabulous book on Parmenides; the reading of Parmenides is not monistic enough for me, but Mourelatos has a great flair for literarily and philosophically sensitive readings and sees the importance of the PSR in Parmenides.

Saul Kripke, Wittgenstein on Rules and Private Languages. Wonderfully clear and deep. The skepticism is powerful; the response to the skepticism is less so.

Donald Davidson, Essays on Actions and Events. So many of the essays are so much fun. “Agency” alone is worth the price of admission. “Mental Events” is still worth reading and still deep.