Della Rocca's Darkest Hour

Abstract

While reading The Parmenidean Ascent, you will likely shake your head in disbelief. “Is Michael Della Rocca serious?” you will probably think “Has he gone mad?”. Well, let's put it like this. If Della Rocca went crazy, he did it with a lot of elegance, method and philosophical rigor. He, in fact, delivers a series of impressive arguments in support of the most important and bewildering thesis of his whole work, namely, strict monism. According to strict monism, there are no relations whatsoever. If we think in metaphysical terms, this means that there are no chairs, tables, stars and human beings. For the existence of all these entities would entail that there are some relations (or, at least, a relation of difference) between all of them. Chairs are not tables, and stars are not human beings. The same can be said about substances, properties, modes, accidents, and many of the other metaphysical categories with which we are so accustomed. Della Rocca, thus, concludes that, according to strict monism, there is nothing but pure, undifferentiated, not at all relational being. “We are looking at pure being” he writes “Undifferentiated being (…) is purely positive and not at all relational” (2020, p. 82).

As we all know, Della Rocca is also a great champion of the principle of sufficient reason (PSR). Much of his philosophy has been informed by an uncompromising endorsement of this rationalist credo, and such a credo does not cease to play an important role in The Parmenidean Ascent. I have, however, no intention to put pressure on his Eleatic endeavor by questioning the PSR. First of all, I do not believe that an attempt to challenge the PSR will score any point against strict monism, for Della Rocca's argument against the existence of relations does not necessarily rely on the PSR. Secondly, I would like to take this opportunity to make a confession and bring myself out of the closet. As with Della Rocca, I am a great fan of the PSR. If this principle is taken to be the hallmark of rationalist thinking, well, let me tell you, I am more than happy to be called a rationalist. For this reason, I cannot be further from thinking that the PSR represents the heart of the problem.¹

Rather than criticizing that Della Rocca employs the PSR, I would like to question how he uses it. In particular, I suspect that the way in which Della Rocca uses the PSR forces him to face the following predicament. On the one hand, his employment of the PSR might commit him to what he calls a ‘darkest hour’. According to Della Rocca, a darkest hour takes place when a philosopher “reject[s] some rationalist commitment” (forthcoming, p. 1) by accepting something – a thing, a fact or even a philosophical principle – as ‘brute’ or ‘arbitrary’. On the other hand, any attempt to avoid such a darkest hour will get some of Della Rocca's arguments in trouble. In particular, I fear that an attempt to avoid his darkest hour will force him to face important issues in wrestling with the so-called PSR-tamers.

In order to justify these fears, section 2 reviews how the PSR is used by Della Rocca in The Parmenidean Ascent and beyond. In so doing, section 2 identifies Della Rocca's two different formulations of the PSR, that is, the PSR₁ and the PSR₂. Section 3 shows that, far from being different ways of presenting the same principle, these formulations are, in fact, two different principles tout court, for they are not logically equivalent. Section 4 argues that, since the PSR₁ and the PSR₂ are two different principles, and since Della Rocca seems to justify the former only, Della Rocca might encounter his own darkest hour twice over: He might encounter it while adopting the PSR₂, and he might encounter it while choosing to use the PSR₁ (for some purposes) and the PSR₂ (for other purposes). Section 4 also argues that, even though Della Rocca can easily avoid the first encounter, the second one is more problematic. For, given what is at Della Rocca's disposal, that is, the PSR₁ and the PSR₂, any attempt to avoid this second encounter will make either his argument against the PSR-tamers unsound or render Della Rocca unable to distinguish himself from the PSR-tamers. Section 5 tries to go beyond what is at Della Rocca's disposal by developing a new version of the PSR₂ which is meant to avoid the issues raised in section 4. However, we soon discover that this further attempt cannot help Della Rocca avoid his darkest hour without additional complications. To conclude, section 6 critically addresses two possible ways in which Della Rocca could resist the arguments developed in this paper.

Della Rocca employs the PSR₁ for exegetical purposes. As an example, consider his interpretation of Parmenides' B8.5–6. According to this fragment, being does not have an origin, that is, being does not come into being. Della Rocca believes that Parmenides supports this idea by relying on the PSR₁, and he reconstructs the argument in the following way. If being comes into being, such coming into being must have a reason. If so, we must explain how being comes into being by appealing to something that is different from being, otherwise we would miss the mark. Since what is different from being has to be non-being, and since non-being cannot be the explanation of the origin of being, the origin of being must be left unexplained. Parmenides, then, concludes that, since the origin of being is left unexplained, there is no such origin. Della Rocca writes: “Because there can be nothing that explains the coming into being of being itself, it follows that there is no such coming into being of being itself. Such coming into being would be a brute fact, and so there is no such coming into being.” (2020, p. 13; italic mine). According to Della Rocca, Parmenides' systematic rejection of what is left unexplained is an expression of the PSR₁. In Parmenides' rejection of brute facts, Della Rocca sees the PSR₁ at work. For this reason, he claims that, as with all the other Parmenidean fragments, B8.5–6 “use[s] – implicitly or explicitly – the PSR_[1]” (2020, p. 16).

The exegetical importance of the PSR₁ can be seen in Della Rocca's interpretation of Bradley as well. According to Della Rocca (2016; 2020), Bradley is firmly convinced that both internal and external relations do not exist, and Bradley supports this idea by dint of an argument which relies on the PSR₁. Della Rocca understands such an argument in the following way. Recall that, according to the PSR₁, if x is posited, x has a sufficient reason. This also means that, if both internal and external relations are somehow posited, they must have a reason. If both internal and external relations exist, there must be something explaining their existence. According to Bradley, “relations” Della Rocca claims “cannot be free floating. (…) Relations must be grounded or metaphysically explained” (2020, p. 74). However, Bradley is aware that the situation is pretty grim. For our attempts to explain the existence of both internal and external relations force us to face a vicious explanatory regress or a case of explanatory circularity. If so, our attempts misfire, and the existence of both internal and external relations is left unexplained. Bradley, then, concludes that, since the existence of both internal and external relations is left unexplained, there are no relations at all. As with Parmenides, Della Rocca takes “Bradley [to be] committed to the broader PSR (i.e. the PSR₁) – everything or fact has an explanation” (2020, p. 74).

One small caveat. As it is clear from chapter 3 of The Parmenidean Ascent, Della Rocca defends a version of Bradley's argument against the existence of relations. Both Della Rocca's and Bradley's arguments are committed to the PSR₁. Having said that, it is important to note that their arguments can be appealing for someone who rejects such a principle as well. For these arguments require that, if relations are posited, they have a reason. This is, of course, an instance of the PSR₁; however, it is not the PSR₁. Della Rocca writes that: “Strictly, Bradley's argument, like mine, explicitly only calls for the explanation of relations and relational facts, not for the explanation of facts or things in general” (2020, p. 74). And, if this is right, I think that, contrary to what has been argued by Priest (2021) and Moore (2025), Bradley's and Della Rocca's arguments cannot be attacked by pointing out that they require an unjustified, implausible or even false principle, that is, the PSR₁.

Della Rocca does not employ the PSR₁ for exegetical purposes only. In his hands, this principle becomes a lethal weapon by way of which he accuses both analytic philosophy and its main heroes of rejecting some important rationalist commitments and, therewith, endorsing a great number of arbitrary, unprincipled, unjustified positions. On the one hand, Della Rocca (2020, pp. 260–291; 2013) uses the crosshairs of the PSR₁ for targeting the whole arc of analytic philosophy. Through an elegant retelling of the (dis-)agreement between Moore, Russell and Bradley, Della Rocca shows that analytic philosophy has often divorced from rationalism and rejected the PSR₁. In so doing, they have also embraced a philosophical method, i.e. the method of intuition, which welcomes a great number of arbitrary and, therewith, undesirable limitations in our thinking. On the other hand, Della Rocca (2021b; forthcoming) uses the crosshairs of the PSR₁ for targeting individual thinkers. He argues that many important philosophers are guilty of abandoning the PSR₁, welcoming something that has no explanation whatsoever and, therewith, facing their darkest hour. If we focus our attention on Frege's philosophy, the distinction between objects and concepts, the fact that objects and concepts ‘hold together’ and the relation between force and content are all cases in point. Della Rocca argues that other examples of arbitrary and unexplained philosophical posits are Russell's distinction between asserted and entertained propositions, Moore's distinction between what is inside and outside the circle of ideas, and Kimhi's difference between the categorematic and the syncategorematic.

As with the PSR₁, x might refer to a thing or a fact, and ‘being posited’ is understood as ‘being / existing’ (whenever x is a thing) or ‘obtaining’ (whenever x is a fact). Moreover, requisites are taken to be the necessary conditions for x to be posited.

Given what I am going to discuss in the next sections, I would like to slow down and pay some attention to the argument, the only argument, in which the PSR₂ is employed. As I have already mentioned, this is an argument which is presented in chapter 10 of The Parmenidean Ascent, and it is meant to show that any attempt to tame the PSR and limit its scope to a specific kind of things or facts is destined to be incoherent. It has two premises and a conclusion. According to the first premise, a tamed or limited PSR entails strict monism. Given a tamed or limited PSR, strict monism is true. According to the second premise, strict monism entails a non-tamed or non-limited PSR. Given strict monism, a non-tamed or non-limited PSR is true. This non-tamed or non-limited PSR is what Della Rocca takes to be the PSR₂. The conclusion, thus, claims that a tamed or limited PSR entails the PSR₂. Given a tamed or limited PSR, a non-tamed or non-limited PSR, that is, the PSR₂, is true. Herein lies the incoherence.

Della Rocca's justification for the first premise is, no doubt, haunted by Bradley's ghost. In order to show that a tamed or limited PSR entails strict monism, he shows that the ways in which the PSR has been tamed or limited and, in particular, the ways proposed by Kant (1999) and Dasgupta (2016) do not take relations and their existence to be without the scope of the principle. This means that, according to these ways of taming or limiting the PSR, relations and their existence are among the things or facts that must have a reason. Della Rocca then presents a Bradleyan argument which shows that, since we cannot deliver a reason for relations and their existence, such relations do not exist. He, thus, concludes that, given these ways of taming or limiting the PSR, there are no relations. In other words, given a tamed or limited PSR, strict monism is true. Once again, let me specify that Della Rocca does not claim that his Bradleyan argument must rely on a version of the PSR. He simply argues that, if you are in the business of a tamed or limited version of the PSR, his Bradleyan argument will be successful. Pace Priest (2021) and Moore (2025), this conditional statement does not rule out the possibility that Della Rocca's argument can be successful without the employment of a tamed or limited version of the PSR as well.

What about the second premise, then? In Della Rocca's attempt to justify this premise, we see his first and last employment of the PSR₂. For he argues that, given strict monism, a non-tamed and non-limited PSR is true. Della Rocca takes such a non-tamed and non-limited PSR to be the PSR₂, that is, if x is posited and x has requisites other than itself, x has a sufficient reason. To see the reason why strict monism entails the PSR₂, recall that, according to strict monism, there are no relations whatsoever and, for this reason, there is only pure, undifferentiated, not at all relational being. Note that the PSR₂ is represented by a conditional statement, and the antecedent of this conditional statement is a conjunction. Given strict monism, the first conjunct is true (because, given strict monism, something is, in fact, posited, that is, pure, undifferentiated, not at all relational being) and the second conjunct is false (because, given strict monism, there are no relations whatsoever and, therewith, there is no relation of difference between something and its requisites either). Since one conjunct is true and the other one is false, the antecedent of the PSR₂ is false as well. The consequent of the PSR₂ is also false. For, given strict monism, there are no relations whatsoever and, therewith, there is no relation of difference between something and its sufficient reason either. The PSR₂ is, thus, true. It is now clear that, given strict monism, the PSR₂ is true. Strict monism, Della Rocca concludes, entails the PSR₂.²

At the beginning of The Parmenidean Ascent, Della Rocca makes a confession. He has often found ironic that the writings of Parmenides, one of the first champions of strict monism and its related radical account of oneness, are available to us in many fragments rather than one unified work. Now it is my turn to make a confession. I too find ironic that someone like Della Rocca, someone committed to strict monism and that very same account of oneness, endorses many formulations of the PSR rather than one unified principle. But, among the countless things I have learnt from Della Rocca, one of the most important is that philosophy is done by arguments. If intuitions or common sense cannot represent a viable path for engaging with a philosophical position, let alone criticizing it, well, neither a quip nor a giggle can either. In what follows, I will try to spell out why I think Della Rocca might face some issues in having these two formulations of the PSR, that is, the PSR₁ and the PSR₂.

Prima facie, the PSR₁ and the PSR₂ have so much in common that we might even wonder whether there is a genuine difference between them. Our wondering finds some further support in the fact that Della Rocca himself takes the PSR₁ and the PSR₂ to be ‘formulations’ of the PSR as if they were nothing more than different ways of spelling out what is ultimately the same principle. At the end of the day, someone might think, both the PSR₁ and the PSR₂ are somehow concerned with whatever is posited. They are about any x which is/exists (whenever x is a thing) or obtains (whenever x is a fact). Moreover, both the PSR₁ and the PSR₂ are concerned with explanations. They give us a domain of explananda, and they also tell us that there is an explanans for all the explananda which are collected in this domain. However, if we focus our attention on how this domain of explananda is characterized, we will immediately realize that the PSR₂ puts on its domain a specification which is absent in the case of the PSR₁. While the PSR₂ claims that the domain of explananda is composed by whatever is posited and has requisites other than itself, the PSR₁ claims that the domain of explananda is composed by whatever is posited only. As we shall soon see, it is because of this further specification that the PSR₁ and the PSR₂ turn out to be two different principles rather than two ways of formulating the same one. For the PSR₁ and the PSR₂ are not logically equivalent, that is, given strict monism, the PSR₁ and the PSR₂ take different truth values. Given strict monism, the PSR₁ turns out to be false and, given strict monism, the PSR₂ turns out to be true.³

To begin with, consider the PSR₁ and recall that, according to this first formulation, if x is posited, x has a sufficient reason. According to strict monism, there are no relations whatsoever and, for this reason, there is only pure, undifferentiated, not at all relational being. Now, if this is the case, the PSR₁ turns out to be false. Since strict monism claims that there is only pure, undifferentiated, not at all relational being, the antecedent of the PSR₁ is true. For something is, in fact, posited, that is, pure, undifferentiated, not at all relational being. Moreover, since strict monism claims that there are no relations whatsoever, the consequent of the PSR₁ is false. For there are no relations whatsoever and, therefore, there is no relation of difference between something and its sufficient reason either. This also means that, given strict monism, the PSR₁ turns out to be false because its antecedent is true and its consequent is false.

What about the PSR₂? Well, given what we have just discussed about the argument in support of the second premise, we should already know that, given strict monism, the PSR₂ is true. But, please, be patient and allow me to present this train of thought one more time. I believe the comparison between the PSR₁ and the PSR₂ might give us some new insights into the argument in question. Later on, I promise, these insights will be helpful. Now, recall that, according to the PSR₂, if x is posited and x has requisites other than itself, x has a sufficient reason. The antecedent of the PSR₂ is a conjunction, and the second conjunct voices what we have already characterized as a specification on the kind of things or facts that, according to the PSR₂, are in the domain of explananda. While the PSR₁ is concerned with things or facts which are/exist or obtain only, the PSR₂ specifies that these things or facts have requisites other than themselves as well. As I have already mentioned, such a specification is important because it plays an essential role in showing that, given strict monism, the PSR₂ is true and it is, therefore, not logically equivalent to the PSR₁.

In order to see why this is the case, we can look back at the argument Della Rocca presents in support of the second premise. From that argument, we have, in fact, learnt that the first conjunct of the antecedent of the PSR₂ is true. For strict monism claims that there is pure, undifferentiated, not at all relational being, and this means that something is, in fact, posited, that is, pure, undifferentiated, not at all relational being itself. From that argument, we have also learnt that the consequent of the PSR₂ is false. For strict monism claims that there are no relations whatsoever and, therewith, there is no relation of difference between something and its sufficient reason either. If we just ignore the second conjunct of the antecedent of the PSR₂, the PSR₂ would be identical to the PSR₁. For this reason, the antecedent of the PSR₂ would be true, and its consequent would be false. As with the PSR₁, strict monism would, therefore, render the PSR₂ false. However, the situation is different exactly because Della Rocca includes the aforementioned specification to the antecedent of the PSR₂, that is, the second conjunct of the antecedent of the PSR₂. As we have already discussed, this second conjunct is false. For strict monism claims that there are no relations whatsoever and, therewith, there is no relation of difference between something and its requisites either. Since one of the two conjuncts of the antecedent is false, the conjunction of the antecedent is false too. This also means that, given strict monism, the PSR₂ is true. For both its antecedent and its consequent are false.

If this is correct, Della Rocca should be able to give us a reason for endorsing the PSR₁ and the PSR₂. He should also give us a reason why he uses the former for certain purposes (e.g. interpreting historical figures, vindicating rationalism and criticizing many of the thinkers who have abandoned this philosophical tradition), and the latter for certain other purposes (e.g. showing that any attempt to tame the PSR is destined to be incoherent). If Della Rocca is not able to do so, Della Rocca would be committed to the same arbitrariness which he desperately wants to avoid, and he would be no better off than all the other philosophers who Della Rocca himself interprets as facing their own darkest hours. Like Frege, Russell, Moore and Kimhi, Della Rocca would reject his beloved rationalist commitments by accepting something – the PSR₁, the PSR₂ and their respective employment – as ‘brute’ or ‘arbitrary’.

At this point, Della Rocca might want to encourage us to stop focusing on The Parmenidean Ascent, and look at his overall production as well. In so doing, we would, in fact, discover that some of his earlier works have been concerned with the possibility of justifying the PSR. Even though I take these justifications to be convincing, it is important to note that, in different ways and for different reasons, all of them are concerned with the first formulation of the PSR, that is, the PSR₁. The second formulation, that is, the PSR₂, finds no justifications in these previous works. Since I have just shown that these two formulations are not logically equivalent, and since the PSR₁ and the PSR₂ are two different principles, both the PSR₂ and the decision to employ these two principles for different purposes seem to remain unjustified in Della Rocca's philosophy. Della Rocca might, thus, encounter his own darkest hour twice. First of all, he might encounter his own darkest hour while adopting the PSR₂ in an arbitrary, unjustified way. Secondly, he might encounter his own darkest hour while choosing to use the PSR₁ (for some purposes) and the PSR₂ (for some other purposes) in an arbitrary, unjustified way.

According to what I have argued in Section 4, it is not possible to avoid Della Rocca's second darkest hour by employing one of the two principles only. If Della Rocca uses the PSR₁, the argument developed in chapter 10 of The Parmenidean Ascent will turn out to be unsound. If Della Rocca uses the PSR₂, he will never be sure to be a PSR-affirmer. To his great disappointment, he might always find himself among the PSR-tamers. In both cases, Della Rocca would face important issues in wrestling with the PSR-tamers. Having said that, I believe there is one last option available. Since the PSR₂ appears to be problematic because it cannot rule out the possibility of finding something with no reason, why don't we modify the PSR₂ in such a way that this threat is finally neutralized? Can we modify the PSR₂ in such a way that Della Rocca can be a PSR-affirmer without the ifs and the buts?

This means that, in order to have an explicitly untamed PSR₂, we need to endorse the PSR₂ and S₁ and S₂. Can Della Rocca use the PSR₂ and S₁ and S₂ in order to be a PSR-affirmer without the ifs and the buts?

It seems to me that the answer is positive. Being supplemented by S₁ and S₂, the PSR₂ is explicitly untamed. For the conjunction of the PSR₂, S₁ and S₂ entails that, whatever we might think about x's requisites, if x is posited, x has a reason. If there is an x which has requisites other than itself, x has a sufficient reason. This is because of the PSR₂. If there is an x which has no requisite at all, x has a sufficient reason. This is because of S₁. If there is an x and requisites do not apply to x itself, x has a sufficient reason. This is because of S₂. Since these options cover all possible ways in which something can have or lack requisites, it follows that, given the PSR₂ and S₁ and S₂, whatever is posited has a reason. Supplemented by S₁ and S₂, the PSR₂ is, thus, logically equivalent to the PSR₁, that is, the untamed principle endorsed by the PSR-affirmers. It is also important to note that, since the conjunction of the PSR₂, S₁ and S₂ is logically equivalent to the PSR₁, and since the PSR₁ is justified, such a conjunction is justified as well. Unfortunately, some problems remain, and it is easy to why this is the case.⁴

Recall that, according to what we have discussed in section 4.2, if Della Rocca tries to avoid his encounter with the second darkest hour by endorsing the PSR₁, he will face an issue, that is, the second premise of the argument presented in chapter 10 will turn out to be false. The whole argument will, thus, be unsound. Since the PSR₁ is equivalent to the conjunction of the PSR₂, S₁ and S₂, Della Rocca faces the same kind of issue by endorsing the PSR₂ and S₁ and S₂. Here is why. The second premise claims that, given strict monism, a non-tamed or non-limited PSR is true. In light of what we are discussing, we take such a non-tamed or non-limited PSR to be the conjunction of the PSR₂, S₁ and S₂. According to S₂, if x is posited and requisites do not apply to x, x has a sufficient reason. Unfortunately, given strict monism, S₂ is false because its antecedent is true and its consequent is false. On the one hand, the antecedent of S₂ is true because both its conjuncts are true. Since, according to strict monism, it is true that something is posited, that is, pure, undifferentiated, not at all relation being, the first conjunct of the antecedent of S₂ is true. Since, according to strict monism, there is being and being is not at all relation, there are no relations between being and its requisites. In other words, requisites do not apply to being and, therefore, the second conjunct of the antecedent of S₂ is true as well. On the other hand, the consequent of S₂ is false because, given strict monism, there are no relation whatsoever and, therefore, there is no relation between something and its sufficient reason either. Since the antecedent of S₂ is true and the consequent of S₂ is false, S₂ is false. Since S₂ is false, the conjunction of the PSR₂, S₁ and S₂ is false too. If so, the second premise of the argument presented in chapter 10 turns out to be false, and the whole argument is, thus, unsound. As with the PSR₁, the employment of the conjunction of the PSR₂, S₁ and S₂ will leave Della Rocca in great trouble. It seems that his second darkest hour looms large.

Before drawing some general conclusions, let me mention one last way in which Della Rocca could resist some of the thoughts developed in this paper. A careful reader might have already noticed that a lot of my arguments rely on the following idea. It is true that, given strict monism, something is posited, that is, pure, undifferentiated, not at all relation being. As we have already discussed in many of the previous sections, this idea plays an essential role in arguing that the PSR₁ and the PSR₂ are not logically equivalent. It is also crucial in showing that, if Della Rocca tries to avoid the second encounter with his darkest hour by working with the PSR₁ only, the argument presented in chapter 10 of The Parmenidean Ascent will fail because unsound. To conclude, the idea that, given strict monism, something is posited, that is, pure, undifferentiated, not at all relation being, is essential in establishing that S₂ is false. If Della Rocca could resist such an idea, he could also resist my arguments and avoid his encounters with the darkest hours. For were it not true that, according to strict monism, something is posited, the argument presented in chapter 10 would not be unsound and S₂ would not be false either.

For the sake of the argument, let's imagine that Della Rocca decides to resist my arguments by claiming that strict monism is false. In particular, let's imagine that, according to Della Rocca, it is false that something is posited, that is, pure, undifferentiated, not at all relational being. In order to support this idea, Della Rocca might argue that, if there were pure, undifferentiated, not at all relational being, such a being would be an object, perhaps the only object, in a certain domain of quantification, and this would require the very same relational metaphysics which strict monism rejects. This train of thought would certainly resist my argument, but it would also commit Della Rocca to some further problems. One of these problems might be explained as follows.

Recall that, according to what Della Rocca claims in chapter 3 of The Parmenidean Ascent, someone might think that the rejection of relations could lead us to two different ideas. On the one hand, it could lead us to the idea that there is pure, undifferentiated, not at all relational being. On the other hand, it could lead us to the idea that there is nothing at all, that is, non-being. Della Rocca, thus, argues that, since the very concept of non-being contains a negation and negations are a specific kind of relation, non-being is not compatible with the radical rejection of relations which is defended by a strict monist. For this reason, Della Rocca concludes that, given strict monism, it is true that there is pure, undifferentiated, not at all relational being and it is false that there is nothing at all, that is, non-being. He, thus, cannot resist my arguments by rejecting the truth according to which there is pure, undifferentiated, not at all relational being. For this is what he himself concludes while arguing against the idea that, given strict monism, there could be nothing at all.

Perhaps, Della Rocca would resist my arguments in an alternative way. Since strict monism claims that there are no relations and there is only pure, undifferentiated, not at all relational being, Della Rocca argues that strict monism cannot be articulated in language. For language is, in fact, relational. It has, for instance, a subject-predicate structure. This means that strict monism is neither true nor false, that is, it is neither true nor false that there are no relations and there is pure, undifferentiated, not at all relational being. In light of strict monism, Della Rocca claims, strict monism itself is simply “nonsensical” (2020, p. 220). Since my arguments rely on the idea that, according to strict monism, there truly is pure, undifferentiated, not at all relational being, Della Rocca's appeal to the nonsensicality of strict monism might be able to resist the arguments proposed in this paper.

Prima facie, this line of thought might seem to raise a problem for strict monism rather than resisting my arguments against it. Strict monism appears to render itself nonsensical and, as such, it appears to be self-undermining as well. Having said that, let's set aside this peculiar aspect of strict monism. Not only is this not the current point of contention between Della Rocca and me, but I also agree with him that, as with Wittgenstein's Tractatus Logico-Philosophicus, the self-undermining nature of strict monism is a feature, not a bug. Let's, then, focus our attention on the fact that it is because strict monism is true that strict monism is nonsense. For, if strict monism was false, pace Della Rocca, it would not be nonsensical. It is because there are no relations, and there is only pure, undifferentiated, not at all relational being, that it is impossible to articulate these very ideas in a meaningful and sensical way. For, if there were relations and differentiated, relational beings, pace Della Rocca, there would be no reason to believe that our language cannot articulate these very ideas. If this is the case, Della Rocca cannot resist my arguments by claiming that strict monism is nonsensical. For his own way of accounting for the nonsensicality of strict monism presupposes that strict monism is somehow true. His own way of explaining the nonsensicality of the idea that there are no relations, and there is pure, undifferentiated, not at all relational being, presupposes that such an idea is somehow true. The problems I raised in this paper are, thus, very much alive.

In this paper, I have argued that Della Rocca encounters his own darkest hour while choosing to use the PSR₁ (for some purposes) and the PSR₂ (for some other purposes). A lot has been done to show that many, if not all, attempts to avoid such a darkest hour are destined to founder. Working with the PSR₁ only? Not a chance! Della Rocca would lose his argument against the PSR-tamers. Working with the PSR₂ only? No way! Della Rocca would endanger the possibility of running his arguments as a PSR-affirmer, and he would not be able to rule out the possibility of finding himself among the PSR-tamers. What about proposing a suitable improvement of the PSR₂? Forget about it! If we modify the PSR₂ with the goal of avoiding the aforementioned problems, Della Rocca would, once again, lose his argument against the PSR-tamers. Back to square one. But, please, do not get me wrong. I do not take my arguments to be conclusive. These are difficult matters, and Della Rocca's defense of strict monism is both complicated and nuanced. However, I would be satisfied if all this can put some pressure on Della Rocca in order to learn how a fellow rationalist like us would wrestle with the kind of issues raised in this paper.

Regardless of the success or failure of my criticisms, The Parmenidean Ascent remains, no doubt, an extraordinary book. I needed to work hard to find what I take to be a(n alleged) darkest hour in Della Rocca's work. My attempts have been made even harder by the fact that his philosophizing is nothing but a remarkably long chain of what he calls ‘finest hours’, that is, “the shining and perhaps brief moment[s] at which the philosopher employs, if only implicitly, some version of the Principle of Sufficient Reason” (forthcoming, p. 1). Here, I believe, lies the real value of Della Rocca's philosophy. Even when Della Rocca fails, if he fails at all, Della Rocca leaves us with the idea of how philosophy can and, perhaps, must be – unprejudiced, brave, challenging, and uncompromising. What we always learn from Della Rocca is that philosophy can and, perhaps, must be this restless search for a safe world in which there are no dark alleys because everything can and, perhaps, must be illuminated by the light of human reason. The process of lighting the world up with human reason might make it burn. That's true. Such a process can make this very same world, its alleys and everything else vanish in our hands. It might even replace all this with pure, undifferentiated, not at all relational being. Della Rocca's strict monism is a witness. However, this is the risk we must take when we welcome Della Rocca's encouragement to philosophize in such an unprejudiced, brave, challenging, and uncompromising way. After this kind of radical philosophizing, Della Rocca promises us, nothing will be the same anymore – neither the world nor us. “When you're dealing with such ideas you feel as though you were taking a witch's ride” Yakov Bok claims in Malamed's The Fixer “After that I wasn't the same man” (2004, p. 76). Not only is this what we should feel after reading any book of philosophy, although Yakov was talking about Spinoza's Ethics, but this is certainly what we experience after turning the last, blank page of The Parmenidean Ascent.