Scepticism against Intolerance? Moses Mendelssohn and Pierre Bayle’s “Dialogue” on Spinoza in Mendelssohn’s Philosophische Gespräche (1755)

: The goal of this article is to argue for the three following theses: (1) that Moses Mendelssohn’s Philosophische Gespräche (1755) offer a rehabilitation of Baruch Spinoza (1632–1677) in explicit opposition to the stigmatization that Spinoza suffered in the German lands from the beginning of the 1670s; (2) that the article “Rorarius” from Pierre Bayle’s (1647–1706) Dictionnaire historique et critique (1697–1698) is a crucial source for Mendelssohn’s strategy to rehabilitate Spinoza; (3) that Mendelssohn’s use of Bayle as a source constitutes an unexplored link between oppressed religious minorities. To show this, the article will consist of an introductory part to set the subject matter and three subsequent parts, one for each of the points that I am going to argue for.


Introduction. Reading Spinoza in Early Modern Germany. The Singularity of the Philosophische Gespräche (1755) 1
The Philosophische Gespräche (Philosophical Dialogues, 1755) were Mendelssohn's first published work: G.E. Lessing (1729-1781), Mendelssohn's friend from 1754 on, reviewed the text and delivered it to the editor in February 1755 (Altmann 1973, pp. 31-50).With regard to the content, the Gespräche are mostly focused on metaphysics, since all four dialogues deal with metaphysical theses attributed to G.W. Leibniz (1646Leibniz ( -1716)).Nonetheless, the metaphysical themes in the work might be divided into two great blocks: while the first and second focus on the relationship between Leibniz and Spinoza, the third and fourth are centred more specifically on analysing some fundamental principles within Leibniz's metaphysics.When discussing the relation between Leibniz and Spinoza along the first half of the Gespräche, Mendelssohn's hermeneutical approach to these philosophers gives rise to a rather peculiar interpretative thesis.Mendelssohn considers Spinoza to be a crucial forerunner of Leibniz, based on the idea that the Ethica contains an almost complete prefiguration of Leibniz's pre-established Harmony 2 .Neophil succeeds in persuading his friend Philopon of this by the end of the first dialogue: Did he not [Leibniz] also assert that changes in the soul can be explained by the same reason or ground through which changes in the visible world can be understood?Did he not assert that everything in the soul succeeds something else, just as it does in the context of things?What else does this mean but what Spinoza says in the words cited: «The order and connection of concepts is one and the same with the order and connection of things» 3 (JubA 1, 9-10; Mendelssohn 1997, p. 103) To the modern reader, Mendelssohn's effort to evince the proximity between Leibniz and Spinoza may seem a curious, even funny philosophical divertimento.But when considering Mendelssohn's work with respect to the reception of Spinoza in the German lands, it turns out that Mendelssohn's move was neither vain nor trivial.The reception of Spinoza by early modern German philosophers has long been analysed, including in classical works from the 19th century (Krakauer 1881; Bäck 1895, which have been progressively completed by several newer approaches (Altwicker 1971; Schröder 1987; Zac 1989; Otto  1994; Pätzold 2002; Goetschel 2004; Jimena Solé 2011 4 ).According to Otto's referential work on Spinoza's reception in eighteenth century Germany, most German thinkers in the late seventeenth and early eighteenth century did not rely on direct access to Spinoza's works.Instead, discussion of Spinozian philosophy was, from very early on, mostly grounded on secondary literature written from a Christian point of view (essentially Protestant, in the German lands), with a distorted emphasis on Spinoza's alleged atheism and its dangers (Otto 1994, pp. 14-33).A quick overview of this process will help us to further understand some of Mendelssohn's assertions in the Gespräche.
The early emphasis on Spinoza's subversive atheism by Protestant philosophers and theologians is no accident at all: the secondary literature by which Spinoza came to be known was initially focused on the Tractatus Theologico-Politicus (1670), the work in which Spinoza took the Old Testament to be a historical piece of literature deserving critical analysis, rather than a source of divine Revelation.Since the Tractatus had been published anonymously, the first reviews of the work did not actually mention its author's name (Otto 1994, pp. 15-16).In the very first public commentary of a Spinozian work in Germany (Programma adversus anonynum de libertate philosophandi, 1670), Jakob Thomasius (1622Thomasius ( -1684) ) claims that the anonymous Tractatus is a perilous publication vindicating freedom of thinking and, most dangerously, discrediting the authority of prophetic messages and Revelation.A few years later, Johannes Musaeus (1613-1681) clarified in his Tractatus theologico-politicus. . .ad Veritatis lancem examinatus (1674) that this fearsome publication was written by Spinoza, a Jew of Amsterdam that was eventually expelled from the Synagogue because of his great impiety.During the 1670s, hence, relevant figures like Thomasius and Musaeus played a central role in promoting the idea that Spinoza was a pernicious atheist leading to both political chaos and religious subversion (Otto 1994, pp. 16-20)  5 .
When the Ethica also came to be known by the 1680s, this religiously oriented criticism of Spinoza had already gained a wide acceptance.The controversy that Christian Thomasius (1655Thomasius ( -1728) ) had with E.W. von Tschirnhaus (1651-1708) because of Tschirnhaus's Medicina mentis (1687) attests to this.Tschirnhaus's idea that the cultivation of one's own reason is the only key to virtue and happiness caused Thomasius to consider him a "Spinozist", that is, a harmful follower of Spinoza's atheistic philosophy 6 .Works discrediting Spinoza as a morally dangerous atheist continued to be published during the following two decades, with examples including Der Spinozismus im Jüdenthumb (1698) by Georg Wachter (1673-1757); Sebastian Kortholt's (1675-1760) De tribus impostoribus Magnus (1700), in which Spinoza is described as a "malus atheus"; the biography of Spinoza written by Johannes Colerus (1647-1707) in 1705; or the work Fatum fatuum (1709) by J. K. Dippel (1673K. Dippel ( -1734)).All these remarkably widespread works contributed to further popularising the image of an atheistic and dangerous Spinoza (Jimena Solé 2011, pp. 89-114).This image persisted and retained its centrality well into the first half of the 18th century, as is apparent in the process that led to Christian Wolff's expulsion from the University of Halle in 1723, and his refutation of Spinozism under pressure in 1737 7 .Undoubtedly, Wolff's case is a paradigmatic example of the enormous strength that the intense stigma retained by Spinoza had several decades after Spinoza's death.
In the light of all this, I shall now proceed to show that Mendelssohn's Philosophische Gespräche are fundamentally aimed at undermining and subverting this stigma on Spinoza.To do so, we will focus first of all on the second of the Gespräche in order to see that Mendelssohn refuses explicitly this stigma and praises instead the treatment of Spinoza's philosophy made by Wolff and Bayle.

From the "Religious Blindness" to the "Well-Founded Critics" of Christian Wolff and Pierre Bayle
By way of introduction to the second dialogue, Philopon and Neophil talk about the oblivion suffered, in their opinion, by the abstract fundamental truths [abstracten Grundwahrheiten] of metaphysics at the time.Neophil accuses modern French philosophers of being overly concerned with mere stylistic and rhetoric issues, thus giving rise to a superficial trend in philosophy in which some German thinkers do also take part.In contrast to allegedly superficial French philosophers, Neophil believes that German thinkers must focus on the unique metaphysical legacy that Leibniz, Wolff and their many German followers have granted them.However, he also admits that the "resistance" to French superficial thinking has not been an exclusive merit of German Christian individuals.Apart from them, the Jew Spinoza must also be credited with making great contributions to the improvement of philosophy: in Neophil's view, Spinoza has the non-negligible merit of enabling the transition from not yet accurate Cartesianism to much more refined Leibnizianism 8 (JubA 1, 13-14).
At this point, Philopon refers to the unfair treatment that Spinoza's philosophy has generally received.In Philopon's view, it is undeniable that Spinoza's philosophy is not without errors, and that such errors could only be vanished by posterior, greater thinkers like Leibniz.However, most of the critiques of Spinoza have not addressed his errors from a philosophical point of view.As Neophil puts it in response to Philopon, "these people [. ..] heap abuse on its naysayer and deluge him, as it were, with calumnies.But the harm they produce outweighs the advantage that they believe themselves to be procuring" (JubA 1, 14; Mendelssohn 1997, p. 107).Mendelssohn makes no explicit references in talking about these critics.Nonetheless, it is most likely that, when alluding to figures that abuse on Spinoza "and deluge him, as it were, with calumnies", Mendelssohn is thinking about those many Christian thinkers basing his criticism on ideas such as Spinoza being a "malus atheus", to put it Kortholt's previously mentioned words.In any case, to consider philosophical doctrines on the grounds of religious fanaticism turns out to be a pernicious act of "calumny".The works by Musaeus, Kortholt and the many others guided by religious ardour are taken to be offensive, unphilosophical pamphlets lacking any intellectual interest at all.
Fortunately, vain criticisms of that kind do not seem to be the only existing approaches to Spinoza.Neophil claims that there is at least one philosopher that took Spinoza's thinking seriously, namely, Christian Wolff: "[o]f all Spinoza's adversaries, only Wolff is not subject to this reproach.This great philosopher, before he refutes Spinozism, casts it in its proper light 9 " (JubA 1, 14; Mendelssohn 1997, p. 107).Neophil's remarks raise immediately a question by Philopon: is not Pierre Bayle worth of mention?Does not the article "Spinoza" in Bayle's Dictionnaire include sensible objections to him?Neophil's answer to Philopon is interesting.No doubt, Bayle succeeded in uncovering mistakes that Spinoza made and, to that extent, Philopon is right in vindicating the Occitan Huguenot.Nevertheless, Neophil goes on, Bayle's problem is that his witty objections are intertwined with unwarranted conclusions: Here and there he [Bayle] has, to be sure, brought up some correct objections to Spinoza.But he has interwoven them with so many sophisms and invalid inferences that he robs them, as it were, of all force.For example, the concept Spinoza appears to make for himself of extension was contested by Bayle with sound reasons, and he showed adequately that extension could not possibly be regarded as an infinite property [unendliche Eigenschaft] of God.But what purpose is served by the array of inferences that he burdens Spinoza with?What use is it to indicate that, in the opinion of Spinoza, if Christians take the field against Turks, God would take the field against God, or that all acts of murder, theft, adultery, and incest would have to be attributed to the supreme being?(JubA 1, 14-15; Mendelssohn 1997, p. 107).
Bayle's place within the reception of Spinoza is therefore quite unique.Contrary to those people that deluge Spinoza "with calumnies", Bayle managed to show that Spinoza's notion of extension is problematic.However, he blended his objections with some unacceptable "sophisms and invalid inferences".From this point of view, Bayle can be said to hold a sort of intermediate position between the traditional religious intolerance against Spinoza and Christian Wolff's well-grounded critiques.On the one hand, Bayle leaves any religious ardour aside to analyse Spinoza's notion of extension in strictly philosophical terms.On the other hand, however, Bayle's excessively superficial and non-systematic character seems to have prevented him from reaching Wolff's profound insight into Spinozian metaphysics.In this regard, it might be useful to bear in mind the cultural rivalry between Germany and France described at the beginning of the dialogue.It is important not to forget that Bayle was born in France and, eo ipso, belongs to the culture that is accused of overlooking metaphysics and adopting frivolous ways of thinking.Nevertheless, this lack did not prevent Bayle from making sensible remarks on metaphysical issues.In other words: beaux esprits like Bayle might not be as deep as other German figures, but can nonetheless become valid correspondents.The German perspective is without doubt a privileged one, but not the only one.
It seems to me that the relevance of this detail may become clearer under the light of the third of the Philosophische Gespräche.This dialogue is focused on analysing some of Leibniz's most basic ontological points, namely: (1) the consideration that the actual world is the best of all possible worlds; (2) the consideration that God created the world in the best of all possible moments.In discussing these themes, Neophil and Philopon reach an unexpected, fascinating conclusion: even Leibniz, who is taken to be the greatest philosopher between the Germans, committed mistakes that must be addressed.The sceptical tone adopted in this dialogue offers an interesting counterpart to the "pro-Leibnizian" enthusiasm traceable in the previous one.As Neophil puts it, every philosopher has been mistaken at some point, and Leibniz is no exception.It is only by being open-minded and engaging in rigorous study that errors can be uncovered.Neophil's intervention in this respect is really worth noticing.In Neophil's sceptical words, the good philosopher is a sort of fearless wanderer who will see the difficulties in his path at the end: To understand Leibniz successfully, it is necessary to become a good Leibnizian first.One must be familiar with his fundamental theses and definitions, just like a diligent student who only aims at focusing strictly on his words.At this point, the difficulties will not have to be sought, but will eventually emerge on their own.[...] [W]hoever reaches the top of the road will eventually encounter them.It will only be necessary not to close one's eyes to what appears there at sight (JubA 1, 21.My translation) From Neophil's point of view, philosophy requires a critical, questioning attitude.Of course, Neophil does not intend to be an all-time doubting sceptic that denies the possibility of knowledge.Rather, he is suggesting more specifically that some philosophical questions can be shown to be problematic or even unsolvable after a proper inquiry.Thus, his sceptical claim is a weak, restricted one: his assessment is that some specific things are seemingly unknowable.However, and here is the relevant point, Neophil emphasizes that being aware of this is philosophically indispensable.When reading any philosopher, including the great Leibniz, one must adopt a sceptical-questioning mood in order to have a real understanding of his doctrine.In other words: good philosophy is necessarily critical, just as Bayle's Dictionnaire surely is.The reflections by which the dialogue comes to end attests to this very remarkably: Philopon: You leave me in doubt: will you eventually destroy the doctrine that I thought I had adhered to with good reasons?
Neophil: I have already told you: the doctrine of the best of the worlds is directly implied by God's properties, and even Bayle, when considering the issue from this viewpoint, had to admit it [the doctrine].Moreover, it is the only one that can provide us with happiness, so that it is necessary for us to cherish it if we wish to gain peace of mind.The remarks against it which I have just exposed to you are only useful because they help us to realize that, as far as this doctrine is concerned, we are far from a perfect certainty, and that much prudence is required to arrive at reliable conclusions in our philosophical speculations about the world 10 .(JubA 1, 26-27.My translation) It is in the light of this third dialogue that Bayle's relevance in the Gespräche begins to be really noticeable.The critical attitude prevailing in it does not only echo Bayle's general approach to philosophers and doctrines in his Dictionnaire historique et critique.Much more specifically, Numesian vindicates Bayle's attitude towards Leibniz's pre-established Harmony.Though Bayle's critical wit grasped the philosophical problems surrounding Leibnizian Harmony, that did not restrain him from accepting its theological plausibility.Inspired by Bayle, Numesian suggests that some beliefs can be held and are worth holding, even though they may be rationally unprovable.
If we were to end our journey here, we would have enough evidence to reflect on the fascinating and hitherto unexplored links between Bayle and Mendelssohn: the third of the Gespräche is nothing less than an anti-dogmatic statement, with the all-time doubting Bayle playing the role of a key, authoritative guest.But this is by no means the end of Bayle's relevance for the work: the first of the Gespräche goes even a step further.To conclude the argument by which Neophil persuades Philopon that Spinoza anticipated Leibniz's pre-established Harmony, Numesian refers to Bayle's criticism of Leibnizian Harmony and shows that such criticisms were already addressed and solved in Spinoza's Ethica.The first dialogue exemplifies the philosophical ethos which is exposed later on, in the third of the Gespräche: to have a real comprehension of Spinoza, Leibniz and their links, it is indispensable to know and face the objections that other critical thinkers (such as Bayle) have raised against them.Let us now return to the beginning of Mendelssohn's work in order to have a definitely complete insight into Bayle's role therein.

The Role of Bayle's Criticisms of Pre-Established Harmony in Rehabilitating Spinoza
Mendelssohn begins the first of his dialogues by placing the reader into the very core of the subject matter at stake.Philopon says that Neophil has suggested that Leibniz's pre-established Harmony was not actually discovered by Leibniz.Neophil pretends not to have suggested that, but Philopon keeps on insisting: "[o]h, the inference is obvious.Did you not say that Leibniz assumed this hypothesis [Hypothes] and brought it into his system 11 ?"(JubA 1, 3; Mendelssohn 1997, p. 96).Because of Philopon's persistence, the initially reluctant Neophil agrees to clarifying his claim regarding Leibnizian Harmony.According to Neophil, the most essential part [das Wessentliche] of the Harmony was devised by another philosopher.Leibniz incorporated that pre-existing thesis into his thinking, his only merit being the act of coining the expression 'pre-established Harmony".This priority debate marks the very first appearance of Pierre Bayle in the Gespräche: Leibniz is supposed to have vindicated this merit in response to Bayle, who had erroneously attributed it to François Lamy 12 .Neophil's slightly humoristic remarks on this include a curious differentiation between "Bayle the historian" and "Bayle the philosopher", which seems specifically aimed at putting his role as a historian into question: True, Leibniz could very easily have been generous with such a triviality.It is more than parsimoniousness if people worth millions are not willing to have even a farthing stolen from them.And yet, Leibniz is to be excused here.You have to assume that he was so selfishly exact not towards Bayle the philosopher, but towards Bayle the critic.Towards Bayle the critic, I say, who has often made crimes out of smaller historical inaccuracies.(JubA 1, 3; Mendelssohn 1997, p. 97) After Bayle's first quick appearance, Neophil asks Philopon to explain what preestablished Harmony exactly consists of.In Philopon's characterization, this hypothesis involves the following core tenets: (1) the changes occurring to each soul (thoughts) can only be caused by the soul itself, through its constitutive representative force 13 ; (2) the changes occurring to bodies (movements) can only be caused by bodies (whether by their selves or by others), through their constitutive motive force; (3) God has arranged a perfect Harmony between every soul and the body to which it is united, a Harmony in virtue of which each and every thought has a specific, correlative body movement and vice versa.Philopon's exposition is no doubt clear, but Neophil raises an objection that brings Bayle back to the table.Philopon has apparently overlooked Bayle's criticisms of Leibniz's Harmony, which is by no means trivial: "[o]f all the opponents who later challenged it, Bayle is, in my judgment, the one who understood it best and, even by Mr. Leibniz's admission, contested it from the right side" (JubA 1, 4; Mendelssohn 1997, p. 98).For Neophil, the issue is therefore clear: as we have seen that Neophil himself argues later in the third of the Gespräche, to really grasp a philosophical doctrine like Leibnizian Harmony involves facing any possible objection to this doctrine, just like Bayle did in his Dictionnaire.
The critiques that Neophil is alluding and Philopon is avoiding to are those included in the article "Rorarius" within Bayle's Dictionnaire.Though he does not make these criticisms explicit until the very end of the first dialogue, I think it is important to briefly contextualize them in order to fully understand Neophil's eventual "solution" of them.The article "Rorarius" is named after the renaissance philosopher Hyeronimus Rorarius (1485-1556).Rorarius wrote a treatise entitled Quod animalia bruta saepe ratione utantur melius homine (1543-1544), in which he defended that the rational capacity of animals is actually superior to that of humans.Bayle observes that such a polemical assertion is contrary to both the (Aristotelian) Scholastic and the Cartesian general accounts of the mind/body relation: Scholastics tend to deprive animal's souls from rational capacity and Descartes even denies that animals have a soul at all.It is after uncovering the problems affecting the Scholastics and the Cartesians that Bayle finally presents Leibniz's Harmony as a third and new hypothesis on the mind/body relation.By means of it, Leibniz is said to have solved some of his predecessors' problems, though suffering in turn from other new ones (Bayle 1991, pp. 214-38).The most relevant one in Mendelssohn's view goes as follows: for Bayle, bodies clearly undergo many processes that can bring about thoughts in the soul (for instance, experiences of pain) that, hence, do not seem to be caused by the soul itself but by bodily processes.The problem is consequently significant: lots of common thoughts are likely to be caused by bodies, bodies being incapable of doing so according to Leibniz's Harmony 14 .
After briefly commenting on the different expositions of the Harmony to be traced in Leibniz's works, the dialogue comes to its central part, namely, the moment when Leibniz's unknown forerunner is unveiled.To begin with, Neophil quotes the work containing a prefiguration of Leibnizian Harmony, specifying neither its title nor its author.His quotation is extracted from the second proposition in the third part of the Ethica: "the body cannot determine the soul to think, and the soul cannot determine the body either to move or to be at rest or to anything else (if something else is possible) 15 " (JubA 1, 6-7; Mendelssohn 1997, p. 100).Despite Neophil's caution, Philopon realizes at once that the quote comes from Spinoza's Ethica.However, this single passage is insufficient to convince him that Spinoza devised pre-established Harmony.At this point, Philopon thinks that this fragment is also compatible with Malebranchian occasionalism 16 .Neophil's disproving of this suggestion comes immediately.As he puts it, Spinozian metaphysics is incompatible with Malebranche's occasionalism for two great reasons: (i) Malebranche claims that human beings have a free will, which Spinoza explicitly denies; (ii) Spinoza claims all bodily movements are explicable in strictly mechanical terms, which Malebranche explicitly denies.
Spinoza's incompatibility with Malebranche is thus clear.However, Philopon still doubts Neophil's idea that Spinoza prefigured Leibniz's Harmony.As he sees it, though Spinoza had attested to the fact that body movements are specifically caused by bodies, he gave no explanation of the changes occurring to the soul and their cause: "[s]uppose I have to concede to you that Spinoza cannot accept the system of occasional causes.Even then he acknowledges only one side of the harmony, namely, what concerns the alteration of the body and the manner of its succession.On the other hand, he observed a perfect silence, I believe, about everything that relates to the soul and the succession of its concepts 17 " (JubA 1, 8; Mendelssohn 1997, p. 102).To convince his friend, Neophil needs only to show that Spinoza did not "observe a perfect silence" concerning the soul and its changes.He does so very quickly, in a noteworthy exchange that is worth quoting: Neophil: In the seventh proposition of the second part of his Ethics, Spinoza says: «The order and connection of concepts is one and the same with the order and connection of things».Remember now what Leibniz brings to his defense against Bayle when the latter objects that, without the effect of another substance upon the soul, it would be inconceivable how the soul is frequently able to pass over immediately from pleasure to displeasure and from sadness to joy.Did he not also assert that changes in the soul can be explained by the same reason or ground through which changes in the visible world can be understood?Did he not assert that everything in the soul succeeds something else, just as it does in the context of things?What else does this mean but what Spinoza says in the words cited: «The order and connection of concepts is one and the same with the order and connection of things»?
Philopon: How wonderful is the makeup of the human intellect!Through erroneous and bizarre principles Spinoza almost stumbles precisely into the view to which Leibniz was led by the soundest and most correct concepts of God and the world.(JubA 1, 9-10; Mendelssohn 1997, p. 103) Neophil's culminating intervention in persuading Philopon brings Pierre Bayle once again into the scene.The crucial step by which Neophil argues for his core thesis involves a three-fold dialogue between Leibniz, Bayle and Spinoza.As has been previously outlined, Bayle's article "Rorarius" includes some objections to Leibniz's pre-established Harmony.Neophil only considers one that seems to be particularly challenging, and he has good reasons to do so.Bayle's point that some processes happening to the soul are seemingly caused by external agents is a direct attack on the ontological grounds of pre-established Harmony: it undermines the crucial belief that each soul is the only cause of its own changes.Neophil's strategy to solve this is primarily based on the distinction between reasons [Grund] and causes [Ursache].For him, the difference between being the reason for something and being the cause of something is fundamental 18 .Reasons are conceptual entities, entia rationis used to explain and understand the facts occurring in the world.Far from being entia rationis, causes are real things that exist in the world and induce therein the facts that we observe and strive to understand.From this point of view, psychic processes can be (and actually are within Leibnizian Harmony) explicable by resourcing to their correlative bodily movements.This does not entail that the phenomena thus understood are caused by the body and its movements.The only thing this entails is that bodily processes can serve as reasons in our understanding of psychic facts, whatever their causes may be.
This move subtly allows Mendelssohn to tackle Bayle's objection.Through Neophil's words, Mendelssohn seems to suggest that a physical agent can appear to be the cause of a change occurring to the soul.This has to do with our understanding of facts, the causes of such facts being irrelevant.From this point of view, Bayle's remark turns out to be no objection at all: it merely insists on the fact that some psychic phenomena are most easily comprehensible by considering the physical movements that they are related to precisely in virtue of pre-established Harmony.In this regard, it is reasonable to say that Leibniz succeeded in solving Bayle's criticism but, as Neophil puts it, he is not the only one to hold this merit: Spinoza had already managed to defeat Bayle before the author of the Dictionnaire even formulated his criticism in the article "Rorarius"! Neophil vindicates this merit for Spinoza based on the parallelism between the attributes of extension and thought that Spinoza states in the second part of his Ethica.Undoubtedly, Mendelssohn neglects here a great number of differences between Leibniz and Spinoza that would promptly discredit his linking of the two.But, when considering Spinoza's parallelism restrictedly, it is undeniable that it prepared the ontological ground for Leibniz's Harmony, i.e., Spinoza had already formulated the idea that the correlation between the order of things (extended objects) and the order of thoughts (souls) is absolutely perfect.
In the end, we can conclude that Spinoza is considered a forerunner of Leibniz under the specific light shed by Bayle's criticisms of Leibniz.When the Baylean remarks are taken into account, Neophil succeeds in showing successively: (1) that bodily movements can provide us with reasons for understanding psychic processes precisely because, in Leibniz's Harmony, the realm of bodies and the realm of souls are causally independent yet perfectly harmonized series; (2) that such harmony between both realms was already asserted by Spinoza, who is therefore credited with devising the core ontological ground of pre-established Harmony.It is true that Bayle's objections to pre-established Harmony vanish after Neophil and Philopon's exchange along the first dialogue.The solving of these criticisms notwithstanding, Bayle's critical effort to pose them turns out to be indispensable.The inclusion of Bayle's sceptical voice in the dialogue leads the characters to a deeper insight into the metaphysical themes at discussion.Bayle's critical insistence is a sort of philosophical key: the sceptical paths it opens are those which, by the end of the dialogue, bring the wanderers Philopon and Neophil to the point where Spinoza's foreshadowing of Leibniz can be appreciated in a much clearer light.

Conclusions: A "Sceptic Brotherhood" against Religious Intolerance?
To bring this article to a conclusion, we should now bring the religiously based critics of Spinoza back into the scene.As we have seen, Mendelssohn begins the second of the Gespräche by alluding to these critics in a clearly reproving tone.Neophil says of their fanatic attack that "the harm they produce outweighs the advantage that they believe themselves to be procuring"; Philopon turns out to be even more emphatic and calls each of these critics "the most depraved scoundrel" with the sole desire "to indulge his evil desires with impunity" (JubA 1, 14; Mendelssohn 1997, p. 106).Mendelssohn's siding with Spinoza is not limited to opposing religiously intolerant and philosophically poor criticism, but further involves substantial praise of him as a forerunner of the most important thesis of Leibniz, said to be the greatest German philosopher of the time.His move against these critics is therefore very significant: if one ceases to deluge Spinoza "with calumnies", he emerges as a crucial contributor to the progress of philosophy, rather than as a target for malicious stigmatization and fanatical disregard.For all of this, it is beyond reasonable doubt that Mendelssohn's Gespräche deploy a rehabilitation of Spinoza in explicit opposition to the religious stigmatization he suffered at the time.
The second thesis that I aimed to defend, namely, that the article "Rorarius" by Bayle is a crucial source in Mendelssohn's rehabilitation of Spinoza, has been extensively argued for in the previous section.As we have seen, Neophil eventually succeeds in convincing Neophil that Spinoza devised the Harmony after presenting Bayle's objections to it and subsequently showing that Leibniz and Spinoza could overcome Bayle's criticism by means of the same ontological thesis, which is precisely considered to be the core ground of pre-established Harmony.Philopon's response to this discovery provides us with some interesting comments on the significance of Mendelssohn's move to rehabilitate Spinoza.At the very end of the first dialogue, Philopon appears to be astonished by the discovery Neophil's inquiry has led him to.In particular, he confesses to be a little worried about Leibniz's occulting of Spinoza's contribution: "[d]o you know that you have now put me in a rather embarrassing situation regarding the uprightness of our Leibniz?How can he allow the learned world to congratulate him for this discovery, since he knew that it did not belong to him alone?"(JubA 1, 10; Mendelssohn 1997, p. 104).Neophil's slightly poetical justification of Leibniz is a final, subtle strike against the "calumny critics": As inappropriate as this behavior would have been for a philosopher like Leibniz, I nevertheless believe that he is to be excused in this case.We would have to chat far into the night, if I were to explain myself fully on this matter.It is sufficient for us to know that there are people who also pass judgments on truths according to a certain genealogy.To repudiate a doctrine, they need only to know that, in the case of this or that writer, it stood in a pernicious kinship with errors.[. ..]If Leibniz had openly confessed that he borrowed the essential part of his harmony from Spinoza, tell me, would these people not have believed from the outset that they found, in the reference to Spinoza's name, the basis for refuting this doctrine?(JubA 1, 10; Mendelssohn 1997, p. 104).
Delicate themes such as Spinoza's relation to Leibniz are likely to be hidden or, if possible, revealed with the utmost care.In order to avoid suffering from intolerant attacks, one must opt for a prudent, even at times veiled form of expression.Mendelssohn seems to be explicitly concerned with this danger and to behave consequently.His ambiguous invitation to only comment on some arduous themes "far into the night" suggests so: it must be noted that, in fact, this pretext serves Neophil to avoid being more explicit about the troubles that caused Leibniz to hide his liason dangereuse with Spinoza, the philosopher "whom the devil himself has hired to subvert divine and human rights" (Domínguez 1995, p. 120), to put it in Musaeus' aforementioned words.
Ambiguous passages aside, it seems to me that Mendelssohn's concern is also traceable to the manner in which the ideas within the Gespräche are conveyed.Mendelssohn writes his very first philosophical work in the form of dialogue.Instead of making a direct exposition of his thinking, the Gespräche contain a conversation between two characters, meant to portray Mendelssohn's own ideas to an extent that is not precisely knowable.Of course, it is reasonable to think that Neophil and Philopon bring different perspectives into play, and that such perspectives serve the purpose of presenting Mendelssohn's philosophical beliefs.But the diluting of such beliefs into a dynamic dialogue between characters with different standpoints can be seen as an act of prudent writing: as a veil that, though fine, nevertheless prevents the reader (especially those readers who show a tendency "to indulge evil desires with impunity") from fully identifying Mendelssohn with any of the characters that he puts into scene.
Be that as it may, Mendelssohn's prudent concern is relevantly linked with Bayle's philosophical ethos and his subsequent strategy to take part in the public sphere.Bayle's delicate religious situation as a Huguenot led to his facing hostile persecution, including tragical moments such as his brother's death in prison after being arrested precisely because of Pierre's own polemical works (Labrousse 1985, pp. 197-201).Taking his difficult biography into account, it cannot be denied that Bayle had first-hand experience of those "most depraved scoundrels" only aiming at "indulging evil desires with impunity".Bayle's own substantial and lucid counteroffensive came with his opus magnum, the Dictionnaire, which was patiently conceived after his firing from his chair at Rotterdam (Labrousse 1985, p. 235 and ss).Bayle conveyed in the Dictionnaire a large number of fascinating opinions, arguments and criticisms of all kinds.Bayle's exposition of these is scattered rhapsodically across the book, with loosely connected themes receiving treatment one after the other.This has made it difficult to pinpoint Bayle's own positions on several issues up until today 19 .
Undoubtedly, Bayle's acts of veiling his opinions and destroying philosophical systems went far beyond Mendelssohn's, and this was certainly due in no small part to the particularly dramatic persecution he suffered.Bayle's intrinsic hermetism notwithstanding, Mendelssohn's Philosophische Gespräche hold Bayle's philosophical attitude in a high regard.The prevailing spirit in the third of the Gespräche has been shown to be a defence of Bayle's approach both to philosophy in general and to Leibniz's thinking in particular.As we have also seen, Mendelssohn's defence of a sceptically toned inquiry is, unexpectedly, articulated at the end of the first dialogue, before his references to Bayle.By means of the sceptical tools that Bayle used to face the Huguenot's persecution, then, Mendelssohn succeeds in rehabilitating a Jew fellow who had suffered from oppression, not unlike Bayle.The Jew Moses Mendelssohn, who had to face harsh religious troubles in his later career, forges an intellectual alliance with the Huguenot Bayle to vindicate the Jew Spinoza against those that stigmatized him with the desire "to indulge his evil desires with impunity".Mendelssohn's softened version of Bayle's sceptical ethos turns out to be a useful weapon against intolerance and fanaticism 20 .
Wolff's claim in his German Metaphysics (1720) that Leibnizian pre-established harmony is the best account of mind/body dualism involved a Spinozist kind of determinism and fatalism for Joachim Langue, the leading voice of the Pietist group opposed to Wolff, who had already been very critical of Leibniz's Essais de Theodicée (Wilson 1995, pp. 446-52).For Lange, the assumption that soul and body remain strictly coordinated at any time denies the possibility of free will, insofar as the soul becomes permanently conditioned by the body to which it is bound and is thus incapable of independent, non-conditioned agency.For a survey on Wolff's accusation of Spinozism and his political and religious significance, see Goldenbaum's recent contribution to the historical context surrounding Wolff's thinking (Goldenbaum 2021, pp. 10-18). 8 It is worth noting that Mendelssohn seems here to be assuming Leibniz's own idea that Descartes is a sort of "ante-chamber of truth", and that his (Leibniz's) philosophy is deliberately aimed at detecting and solving the problems within Cartesian thinking that had prevented Descartes from further achieving what, according to the prior metaphor, we might call "the chamber of truth".In this regard, see Anfray's recent contribution (Anfray 2019, particularly pp. 721-26).The way in that Mendelssohns says Spinoza to make the transition to Leibnizianism possible will be exposed at length in the next section.9 Wolff made an explicit refutation of Spinozism some years after his expulsion from Halle.He included it at the end of the second part of his Latin Theology (1737), that is, within the section devoted to atheism, in the chapter entitled "De paganismo, manicheismo, spinozismo et epicureismo" ("On Paganism, Manichaeism, Spinozism and Epicureanism").For Wolff's refutation of Spinozism, see Buschmann (1994).Bayle's relationship with scepticism is an undeniably complex issue.Although a very small minority denies it (see Hickson 2023), most of current scholars consider Bayle to be some kind of sceptic, led by Popkin's auhtoritative consideration of Bayle as the "supersceptic" culminating the sceptical crisis of early modern times (Popkin 2019, pp. 628-66).Whatever the extent of Bayle's de dicto adherence to scepticism, I think it's reasonable to see the critical Dictionnaire as de facto exemplifying the Pyrrhonian approach to philosophy that Bayle himself describes in the 1702 version of the article "Pyrrhon".As Bayle puts it: "they [the pyrrhonists] have a kind of weapon that they call the diallel, which they wield at the first instant it is needed.After this is done, it is impossible to withstand them on any subject whatsoever.It is a labyrinth in which the thread of Ariadne cannot be of any help.They lose themselves in their own subtelties [. . .] since this serves to show more clearly the universality of their hypothesis that all is uncertain, not even excepting the arguments which attack uncertainty. . .Theologians should not be ashamed to admit that they cannot enter a contest with such antagonists.[. ..]The small boat of Jesus Christ is not made for sailing on this stormy sea, but for taking shelter from his tempest in the haven of Faith" (quoted from : Popkin 1997, p. 3).Regarding the constitutive Pyrrhonian character of Bayle's Dictionnaire, see Rothenberger (2021, specially pp. 141-223).I will return to Bayle's philosophical ethos within the final section of the article.

11
Throughout the text, Mendelssohn refers to pre-established Harmony by using the expressions 'Hypothesis', 'Opinion' [Meinung] and, less often, 'Doctrine ' [Lehrmeinung].This fact is interestingly related with the Wolff-Lange affair.In his German Metaphysics (1720), Wolff presents what he considers to be the three possible accounts of the mind/body relation, mirroring the three-fold division between the Aristotelian-Scholastic, the Cartesian and the Leibnizian mind/body systems that Leibniz himself seemed to sketch for the first time in his 1695 Système nouveau (Leibniz 1986, pp. 201-27).Each account is singularized by a specific kind of causal relation between bodies and souls.(1) Natural influence [natürliche Einfluss] is based on the existence of "reciprocal action" [Wirkung in einander] between bodies and souls, so that bodily movements can cause thoughts and vice versa; (2) in the comunion [Gemeinschaft] defended by the Cartesians, body and soul simply "give occasion" [Gelegenheit geben] to God's action, God being the only One with real agency to cause effects in the world; (3) Leibniz's pre-established Harmony [vorherbestimmte Harmonie] involves two separate, yet divinely (and thus perfectly) coordinated causal realms, one including bodies and their movements and the other constituted by souls and their thoughts.Wolff successively refutes natural influence and occasionalism, showing pre-established Harmony to be the only plausible approach.Though he is not really explicit on that, Wolff thus seems to suggest that Leibnizian Harmony is the only true account of mind/body dualism.(GW I.2,.Things become slightly different in his posterior Psychologia Rationalis (1734).After the many troubles caused by Lange's ardour against pre-established Harmony (see note 7), Wolff explicitly granted all three systems on mind/body relation with the status of mere "hypotheses", that is, of provisional theories subject to possible refutation.Natural influence, occasional causes and pre-established Harmony are thus placed on the same hypothetical level, and none of them can be considered "the best" or "the truest" stricto sensu.In this respect, it is very important to note that, in note L within the article "Rorarius" of his Dictionnaire, Bayle had also used the label "hypothesis" [hypothèses] for any of the three existing approaches to mind/body dualism (following Leibniz's Système) (Bayle 1991, pp. 235-38).Therefore, Wolff's trouble with the Piestists lead him to mirror Bayle's much more prudent treatment of mind/body dualism.For all this, Mendelssohn inherits both Bayle's and also Wolff's later terminology regarding mind/body dualism, in a seemingly cautious gesture against those with a tendency to deluge their rivals "with calumnies".12 The French theologian François Lamy (1636-1711) used the expression 'Pre-established Harmony' [Harmonie préetablie] in the second of the five volumes within his De la connaissance de soi-même (On knowledge of oneself, 1694-1698; Bayle 1991, p. 245).Incidentally, it is important not to confuse François Lamy with Bernard Lamy (1640-1715), a mathematician at the time, mostly centred on Mechanics and Geometry and with some incidental incursions into the fields of Logics and Language (La Rhetorique ou l'art de parler-Rhetoric or the art of speaking-1675).I do emphasize this because, in Dahlstrom's English translation, the Lamy adduced by Bayle is erroneously said to be Bernard Lamy.
13 Following Wolff (GW I.2, 56-68), Mendelssohn implicitly assumes that each soul essentially owns a specific representative force [Vorstellungskraft] of its own, which in fact constitutes it as a unique and indivisible substance [Substanz].14 Bayle's attacks on Leibnizian Harmony are the result of a long an interesting discussion between Bayle and Leibniz, beginning immediately after the publication of Leibniz Système nouveau in a June 1695 issue of the Journal des Savants, and lasting for some years after the first edition of the Dictionnaire appeared.For details of this discussion, see Barber (1955, pp. 56-69), Fichant (2015) and Pelletier (2015).15 Interestingly, Mendelssohn does not use the recent German translation of the Ethica by Johann Lorenz Schmidt (1702-1749) to quote Spinoza, but opts instead for adapting Spinoza's text on his own.Schmidt published his translation in 1744, including both the Ethica and Wolff's refutation of it, under the title B. V. S. Sittenlehre widerleget von dem berühmter Welteisen unserer Zeit Hernn Christian Wolff (The Ethics of B.V.S. refuted by the well-known philosopher of our time, Mr. Christian Wolff ).Regarding Schmidt's translation and the hostile reaction it aroused within the still fiercely anti-Spinozian Pietist establishment, see Goldenbaum (2011).Incidentally, this constituted a good reason for Mendelssohn to avoid its use.

16
As already exposed in note 11, we must not forget that, at the time, occasionalism is said to be one of the three possible systems to explain mind/body dualism.17 In the 1755 edition, Philopon's question is much more generic than in the second, 1761 version of the text.In it, Mendelssohn completes Philopon's intervention by specifically facing the great problem posed by Bayle and to be tackled by Neophil all at once: "He [Spinoza] says, to be sure, that the actions and passions of the soul spring from their adequate and inadequate concepts.But what explains those alterations of the soul that are apparently based, not on the foregoing state of the soul, but on the movements of the body instead?If sensuous concepts are things the soul undergoes, where does Spinoza show us the way in which we are to derive these from inadequate concepts (without the help of the body and its limbs)?"(JubA 1, 344 ;Mendelssohn 1997, p. 102). 18 This subtle distinction between cause and reason is a central one within Wolff's philosophy.As Wolff clarifies in his German Metaphysics, when a thing A contains something that makes it possible to understand what another thing B is, A contains the reason for B and, therefore, A is the cause of B. The example he gives in to illuminate the distinction between both concepts is illustrative: when someone wants to go out because the weather is good, the representation of the good weather is the reason [Grund] of his desire, and the soul, which produces the representation, is the cause [Ursache] of it (GW I.2, 56-68).Philopon's prior exposition of Leibnizian Harmony includes an interesting modulation of Wolff's distinction which, in fact, makes Mendelssohn much closer to Leibniz's Système than to Wolff's German Metaphysics.As Philopon puts it, every change that the soul undergoes occurs (1) by instigation [auf Veranlassung] of the body, though (2) actually caused by the soul's constitutive force [ursprungliche Kraft], so that the soul is the only real cause of it.Similarly, everything happening in the body occurs (1) by instigation of the soul but (2) exclusively caused by the action of mechanistic-bodily forces [körperliche mechanische Krafte].On the basis of this subtle differentiation between "cause" [Ursache] and "insitgation" [Veranlassung], Philopon claims that both psychic representations and bodily movements have two different sufficient reasons [zureichenen Gründe], that is, two complementary ways of being explained and understood.As for the soul's representations, for instance, the reason through which they emerge [Grund wodurch] is to be found in the mechanical movements of the body, while the final reason or reason why they emerge [Grund zu welchen Ende oder warum] lies in the soul's constitutive force causing the representation.(JubA 1, 4-5).

19
For a general survey of the so-called "Bayle enigma", see Lennon (1999). 20 In this regard, it is interesting to note that this sort of instrumental use of scepticism in the context of religious conflicts reappears at the end of Mendelssohn's career, by the time that Jerusalem (1783) was published.See Strauss (2018). 10