In this paper,1 I study an aspect of the historical background for the ‘idealist’ reading of Spinoza that, in the wake of Michael Della Rocca’s influential hyper-rationalist approach to Spinoza and an associated spike in interest in the relations between Spinoza and both German and British idealism, has become the topic of a still growing literature over the last decade or so.2 Here, I want to trace this history further back than usual and focus on an earlier idealist reading of Spinoza, indeed among the earliest of them all. It can be found in the Elucidarius cabalisticus, sive reconditae Hebraeorum philosophiae brevis et succincta recensio by Johann Georg Wachter, a kabbalist interpretation of Spinoza published in 1706. I am principally interested in the importance that Wachter’s book had for German philosophy in the second half of the eighteenth century. Many commentators have discussed, in more or less detail, what the protagonists in the Pantheissmusstreit thought about the relation between Spinozism and Kabbalah generally.3 I believe, however, that the exact contribution of Johann Georg Wachter’s work has not been adequately appreciated. I argue that the Elucidarius cabalisticus likely contributed importantly to the discussions that eventually produced the staunchly idealist reading of Spinoza that dominated the German Spinozabild from Moses Mendelssohn’s Philosophische Gespräche (1755) through the Pantheismusstreit up to the second edition of Herder’s Gott: Einige Gespräche (1800), culminating with Hegel’s ‘acosmist’ reading of Spinoza in the 1825–26 lectures on the history of philosophy.4 If I am correct about that, it is of course not only of importance for Spinoza scholars. Anyone familiar with German philosophy in the late eighteenth and early nineteenth century is aware of the deep impact that Spinoza’s philosophy had on philosophy generally during that period (see, e.g., Förster and Melamed 2012; Lærke and Moreau 2021). At first, this was because the discussion of Spinozism was inextricably wound up in the contemporary issue regarding the religious compatibility of Enlightenment philosophy with Christian religion. Later, it was because Spinoza’s monism, when dressed up in new dialectical garb, represented a precursor to the kind of pantheist natural philosophy championed by the German idealists. If, however, the interpretation of Spinoza was such a central issue for German philosophy generally, and if Wachter, along with other more well-known sources such as Pierre Bayle and Christian Wolff, helped shape the interpretation of Spinoza, then, by extension, Wachter and his assimilation of Spinoza to Kabbalah likely contributed to steering German philosophy in the direction it took during the Enlightenment and in German Idealism.

As we shall see, Wachter was explicitly cited and extensively discussed in some key texts of the Pantheismusstreit, in Jacobi and Herder in particular. This is not disputed. Here, however, I try to determine Wachter’s point of entry into these German debates, in texts where Wachter’s presence is more discreet and his possible impact less easy to demonstrate. I focus on Moses Mendelssohn’s 1755 Philosophische Gespräche. Those dialogues and the interpretations of the relation between the philosophies of Spinoza and Leibniz they propose are well-known. Alexander Altman and Dominique Bourel have written important papers on the topic (Altmann 1966; Bourel 1981; Bourel 1988). Detlef Pätzold has studied the dialogues in detail in the context of Mendelssohn’s broader engagement with Spinozism (Pätzold 2011). Moreover, the central role of the Philosophische Gespräche for the later pantheism controversy is broadly acknowledged. The book was debated throughout the entire second part of the eighteenth century. Lessing, for example, criticized Mendelssohn’s analyses for being ‘sophistical’ in a famous text of 1763 entitled Durch Spinoza ist Leibniz nur auf die Spur der vorherbestimmten Harmonie gekommen (Lessing 1970–79: vol. 8). Mendelssohn responded in a letter written early in the summer the same year, a text I shall return to later in this paper. Moving another two decades forward in time, in the 1785 Über Die Lehre des Spinoza in Briefen an den Herrn Moses Mendelssohn, Jacobi used Mendelssohn’s analyses in a way contrary to their original purpose, trying to discredit Leibniz by means of the association to Spinoza (Jacobi 1994). Finally, Mendelssohn himself reused his own interpretation, in Morgenstunden (1785) and in An die Freunde Lessings (1786), but this time in order to reject Spinoza rather than the contrary (Mendelssohn 2011; Mendelssohn 1786).

The interpretation of the relations between Leibniz and Spinoza that Mendelssohn developed in the Philosophische Gespräche thus had considerable influence throughout the entire second half of the century as a common reference for the protagonists in the Pantheismusstreit. It was an interpretation on which most of them took a position and, for this reason, it also provided a shared framework for them to engage with each other. Mendelssohn’s text set the stage for their philosophical discussions by laying down some of the basic terms of a shared image of Spinoza that largely persisted up until, and including, Hegel’s time. That image was largely what is called today, and what Mendelssohn already called, an ‘idealist’ image of Spinoza. It is thus my claim that, if it can be shown that Wachter’s work informed the idealist reading of Spinoza that first occurred in Mendelssohn’s dialogues, it can also be argued that Wachter contributed to the emergence of that reading in general.

Wachter wrote two books dedicated to the relations between Spinoza and Kabbalah. Before the Elucidarius cabalisticus appeared in 1706, he had already published a book entitled Der Spinozismus im Jüdenthumb oder die von dem heutigen Jüdenthumb und dessen geheimen Kabbala Vergötterte Welt in 1699. In both books, he defended the thesis that Spinoza had given philosophical voice to Kabbalah or that Spinozism was a conceptually distilled expression of the ‘philosophy of the Hebrews’.

The first book, Der Spinozismus im Jüdenthumb, was a reply to a certain Moses Germanus, the ‘German Moses’, in reality named Johan Peter Spaeth. A former collaborator of Baron Christian Knorr von Rosenroth—a German Rosicrucian and editor of the Latin text anthology Kabbala Denudata (1677–84)—Spaeth was a tormented Christian who had vacillated between various confessions until finally converting to Judaism and embracing Kabbalah. Incidentally, this conversion story had been somewhat of an embarrassment for those Christian philosophers and theologians who explored Jewish thinking, including Kabbalah, in order to strengthen Christian doctrine (Coudert 2004; Rensoli 2011). In this first book, Wachter then set out to demonstrate, against Spaeth, that Kabbalah was incompatible with all religion since it was really a form of Spinozism. At that time, as the vast majority of his contemporaries, Wachter considered Spinozism an atheistic and thus deplorable doctrine.

In his second book, the Elucidarius cabalisticus, Wachter took a very different approach to the same topic. Here, he replied to the German orientalist Johann Franz Budde who, in his Defensio cabbalae Ebraeorum from 1700, had defended Kabbalah against the accusation of Spinozism. Budde argued that the Kabbalah denounced by Wachter was not authentic but only Isaac Luria’s recent pseudo-cabbala. Wachter’s focus changed accordingly: whereas in the first book he simply aimed at establishing a connection between Kabbalah and Spinozism, in the second, he was rather discussing which version or interpretation of Kabbalah was similar to Spinozism and whether this Spinozist type corresponded to the authentic Kabbalah or not. This difference in approach was, however, not the only or even the most remarkable change in Wachter’s assessment. He had also changed his mind regarding the religious orthodoxy of Spinozism. He now argued that Spinoza ‘has acknowledged the divinity of Christ and the truth of the entire Christian religion’ (Wachter 1706: 7). In the first three parts of the Elucidarius, dedicated, respectively, to the origin, propagation and the doctrine of Kabbalah, he thus attempted to demonstrate the agreement between Kabbalah and Christian religion. And in the fourth part, entitled De consensus cabalae et Spinozae he went on to show how Spinozism could ‘elucidate’ this genuinely Christian Kabbalah by providing it with the philosophy corresponding to it.

Wachter is far from unknown among intellectual historians. His books have received a fair amount of attention in the work by Gerschom Scholem, Winfried Schröder, Jonathan Israel, Wilhelm Schmidt-Biggeman, Martin Mulsow, Miquel Beltran, and several others.5 The two books are often considered important contributions to the more subversive or, in Israel’s vocabulary, ‘radical’ early German Enlightenment. Wachter is, however, rarely cited as a genuine authority on Spinoza’s philosophy. And yet, in Spinoza’s own time, he was considered differently. John Toland, who met and discussed with Wachter at the Court of Berlin just after 1700, noted in his Letters to Serena that Wachter was generally considered a great expert on Spinoza’s philosophy.6 Gottfried Wilhelm Leibniz, who also met Wachter in Berlin at that time, took a very serious interest in Wachter’s work in philosophy and read several of his works.7 Most importantly, around 1707, he composed a detailed commentary on the Elucidarius cabalisticus (the Leibniz editor Louis Alexandre Foucher de Careil first published the text in 1854 under the decidedly misleading title Réfutation inédite de Spinoza [Leibniz 1854]).8 Leibniz also discussed the debates between Spaeth and Wachter in the Essais de théodicée of 1710 and acknowledged the validity of Wachter’s approach when noting that ‘Spinoza … was well-versed in the Kabbalah of his nation’ (Leibniz 1875–90: 6:55 and 6:336). These brief remarks in the Essais de théodicée are noteworthy because the book figures among the most widely read philosophical texts in the eighteenth century. The German polymath thus contributed in an important way to the diffusion of Wachter’s thesis. But he was not the only one. We also find Wachter discussed in Jacques Basnage’s Histoire des Juifs ([1706–11] 1716), Don Gabriel Alvarez de Toledo y Pellicier’s Historia de la Iglesia y del Mundo (1713), Jacob Friedrich Reimmann’s Versuch einer Einleitung in die Historie der Theologie insgeheim der Jüdischen Theologie ins besondere (1717), the English Freemason Andrew Michael Ramsay’s Le Psychomètre (1735) and The Philosophical Principles of Natural and Revealed Religion (1748), André François Boureau-Deslandes’s Histoire critique de la philosophie ([1737] 1756), Johann Jacob Brucker’s Historia critica philosophiae (1742–44), and numerous others (Lærke 2008: 925–26).

This all goes to show that, throughout the first half of the eighteenth century, Wachter’s books were read, commented upon, and appreciated all over Europe. It should come as no surprise, then, that Der Spinozismus im Jüdenthumb and the Elucidarius cabalisticus both figure in the inventory of Moses Mendelssohn’s personal library, or that Wachter’s theses are mentioned numerous times in Mendelssohn’s texts (Meyer 1926: 44 and 52, cited in Altman 1973: 866 n. 10).9 In Morgenstunden, he notes how ‘Wachter, in a peculiar treatise, has indicated that this opinion has its origin in cabbalistic fanaticism and is entirely constructed upon it,’ here adding a reference to the Spinozismus im Judenthumb (Mendelssohn 2011: 75). Moreover, he explicitly endorsed Wachter’s general thesis when affirming, in a 1783 letter to Elise Reimarus, that ‘Spinozism is built on a Kabbalistic basis and has grown from a Kabbalistic trunk’ (Mendelssohn 1972–: 8:264).

Important for our purposes, however, Wachter’s association of Spinoza and Kabbalah features not only in these various texts from the mid-1780s but appears already three decades earlier in 1755 when Mendelssohn wrote the Philosophische Gespräche. Micah Gottlieb thus highlights an interesting recollection regarding Mendelssohn’s attitude toward Kabbalah narrated by Mendelssohn’s friend Friedrich Nicolai in his 1799 autobiographical Über meine gelehrte Bildung:

Nicolai does not date this recollection specifically. But only a few pages earlier he explains that he first became acquainted with Mendelssohn late 1754 or early 1755, via Lessing (Nicolai 1799: 41). And he relates their conversation about Kabbalah immediately before offering an account of some meetings in coffee houses that took place in 1755 (Nicolai 1799: 44). So presumably the conversation took place around that time—that is to say, exactly at the time when Mendelssohn published the Philosophicshe Gespräche! Evidently, the association of Spinoza and Kabbalah was already on his mind at that point.

Mendelssohn’s most important interlocutors and many contemporary philosophers, including Lessing, Jacobi, Herder, Hamann, Kant, Schlegel and others, were also familiar with Wachter. For example, when Jacobi in Über die Lehre des Spinoza in Briefen an den Herrn Moses Mendelssohn proclaimed Kabbalah to be nothing but ‘underdeveloped Spinozism,’ he explicitly referred to Wachter’s Elucidarius cabalisticus.10 Wachter’s theses also inspired strong reactions. Writing to Jacobi in April 1787, Hamann denounced the Elucidarius as a ‘disgusting book’ (ein eckles Buch) (Hamann 1955–79: 7:169). And when Herder prepared the second edition of Gott: Einige Gespräche, published in 1800, he thought it worthwhile to dedicate several pages to refuting Wachter’s at that point century-old interpretation (Herder 1940: 155–56 and 208–9). If the philosophical and theological merits of Wachter’s Kabbalistico-Spinozist doctrine were evaluated very differently by the German philosophers, they almost unanimously granted that Wachter’s approach was pertinent. To my knowledge, only Herder contested the association of Spinozism and Kabbalah (Herder 1940: 208–9).

In spite of all this, Wachter’s contribution to Spinoza interpretation in Germany has been generally minimized, rejected, or even disdained. David Bell, for example, gives the following negative assessment of Der Spinozismus im Judenthumb in the context of a generally unfavorable evaluation of the early Spinoza commentators:

The criticism is extraordinarily virulent. It is a good illustration of the curious exorcism that Wachter has been the victim of in some commentaries on German Enlightenment philosophy. For Bell, Wachter’s contribution was only negative: his books served only to mutilate Spinoza’s system. When not derided in this way, Wachter is most often simply ignored.11 Even the foremost expert on Wachter’s work, Winfried Schröder, rejects the idea that Wachter played any significant role in shaping the German Spinozabild during the Pantheism Controversy (Schröder 1987: 114–15).

I believe, however, that we should grant Wachter a more prominent place. I do not deny that his work represents a very peculiar version of Spinoza’s doctrine, a transformation of Spinozism in which Spinoza would most likely find it hard to recognize himself. After all, Spinoza mentions Kabbalah only once in his entire work and here only to discard it as ‘trifles’ and ‘madness’ (Spinoza 1985–2015: 2:217). That did however not prevent Wachter’s Kabbalist reading from heralding a transformation in the perception of Spinoza that became crucial for the reception in Germany during the next century. For he proposed a reading in which Spinoza did not, as it was most commonly argued in Wachter’s own time, tend toward materialism and atheism, but rather toward idealism (i.e., the doctrine that all that is, is ultimately ideal) and acosmism (i.e., the doctrine that the world ultimately does not exist). For he attributed to Spinoza the view that all that is, is ultimately God, and that God is a purely spiritual being. This is already apparent from the subtitle of Der Spinozismus im Jüdenthumb: ‘On contemporary Judaism and the deified world of its secret Kabbalah.’ The more difficult question is, however, how Wachter’s reading, in more or less dissimulated form, found its way into the more mainstream philosophical discussions of Spinoza and how it impacted them. And in order to gain clarity on this point, I think we must turn to Wachter’s second book, the Elucidarius cabalisticus, and to the way it compares with Moses Mendelssohn’s 1755 Philosophische Gespräche.

Let us begin with the Philosophische Gespräche. In the first two dialogues, Mendelssohn discusses Leibniz, Spinoza and the relationship between their doctrines. Mendelssohn’s aim is to present Spinozism as a respectable position by assimilating it to Leibnizianism or, to be more precise, by assimilating it to what is sometimes called Leibnizio-Wolffianism.

In the first dialogue, Mendelssohn suggests that Spinoza provided the blueprint for Leibniz’s ‘pre-established harmony,’ understood by Mendelssohn as the doctrine of the relations between the mind and the body put forward by Leibniz in the 1695 Système nouveau de la nature et de la communication des substances. According to that doctrine, ‘God has originally created the soul, and every other real unity, in such a way that everything in it must arise from its own nature by a perfect spontaneity with regard to itself, yet by a perfect conformity to things without’ (Leibniz 1985: 457).12 Mendelssohn correlates it with proposition VII of the second part of Spinoza’s Ethics, according to which ‘the order and connection of ideas is the same as the order and connection of things’ (Spinoza 1985–2015: 1:451).

The analysis is not original. It was first proposed by the Cartesian Ruardus Andala in his Dissertationum philosophicarum pentas from 1712 in an attempt to counter Leibniz’s repeated accusations that Cartesianism inevitably leads to Spinozism by turning Leibniz’s weapon against himself, arguing that Spinoza’s doctrine was primus parens harmoniae praestabilitae (Andala 1712).13 The Halle pietist Joachim Lange revived Andala’s claim in his Causa Dei et religionis naturalis adversum atheismum ([1723] 1727), this time in an attempt to compromise the Leibniz-inspired philosophy of Christian Wolff with a suspicion of Spinozism (Lærke 2008: 48–50; Pätzold 2011: 112–16). Mendelssohn, however, in line with his general approach, used the same analysis for the contrary purpose, namely to rehabilitate Spinoza by pointing to the proximity to Leibniz who, in the meantime, had become firmly established as a respectable philosopher in Germany. Wachter, as far as I can judge, plays no role in this debate about the origins of pre-established harmony.

In the second dialogue, the one I am primarily interested in here, Mendelssohn enquires about the status of the world in Spinoza and the relation between this Spinozist conception and Leibniz’s conception of the world. Now, according to Leibniz’s theory in the Essais de théodicée (1710), God chooses the best of all possible worlds. Before creating the world, God conceives in his intellect infinitely many possible worlds which he then compares with respect to perfection. Between these possible worlds, he chooses only one, the best, and by his will, coextensive with his power, he brings this best world into existence. This world willed by God is the unique world in which we actually live. The phenomenal reality of this actually existing, chosen world consists in the fact that the series of events it includes is expressed or perceived by infinitely many individual created substances or ‘monads’, whose inner substantial activity consists in spontaneous perception. For Leibniz, however, the possible worlds qua possible also have a kind of existence, namely, precisely, a possible existence that Leibniz also describes as an ideal existence. This ideal existence is grounded in the fact that the possible worlds are contained and expressed essentially in the divine intellect as eternal truths and thus perceived by God. As Leibniz puts it in the Monadology, §§ 43–44:

In the Philosophische Gespräche, Mendelssohn reformulates this famous theory by suggesting that, for Leibniz, there is an Urbild and a Nachbild of the world, or what we might translate as an ‘original image’ and a ‘derived image’.14 The Urbild is a detailed plan of the world insofar as it is represented in God’s intellect as one possible creation among other possible creations, all equally conceived in God’s intellect. The Nachbild of the world is the actual, existent world, insofar as it is realized in the perception of infinitely many individual created substances or monads created by God. In order for the world as Urbild to enter existence, there must be a ‘complement to possibility’ as Mendelssohn puts it with a notion originally coined by Christian Wolff to define existence in his Philosophia prima, sive Ontologia (See Wolff 1736: 143).

Mendelssohn, however, does not refer to the Ontologia when accounting for this theory in the Philosophische Gespräche. Instead, he leans on a passage in Wolff’s Theologia Naturalis, II, § 92, where the latter maintains that ‘God delimits all the possible modes of the primary possibilities and, at the same time, he knows those limits very distinctly’ (Wolff 1741: 62). And the way that Mendelssohn paraphrases this particular passage is not without interest in the context of Kabbalah. He writes that, according to Wolff, ‘God entertained the possibility of contingent things since he could think of his own perfections next to a certain degree of limitation [einem gewissen Grade der Einschränkung]’ (Mendelssohn 1972–: 1:16, trans. in Mendelssohn 1997: 109). I shall not attempt to unpack the exact implications of this mysterious statement—it is not relevant to the main concern of this paper. But we should note how Mendelssohn transforms Wolff’s modal discussion of primary possibilities into a discussion of divine ‘perfections’ and ‘degrees’—notions that have a distinctly more ontological ring to them than Wolff’s original analysis, especially given the Spinozist and Leibnizian contexts of Mendelssohn’s overall philosophical development.15 For, on those ontological terms—and without claiming to propose anything more than an intriguing conjecture—the underlying doctrine begins to sound conspicuously like the doctrine of tsimtsum, i.e., the conception of divine self-limitation or self-contraction that governs the creation story in the Lurianic Kabbalah, a conception that stood centrally in the doctrines of practically all the Kabbalists of Christian extraction, including Wachter (Wachter 1706: 31–32; Wachter 1699: 84–88).16 It would, of course, be frivolous to trace Mendelssohn’s talk of ‘Einschränkung’ back to any Kabbalist in particular, including Wachter. The Lurianic doctrine was common knowledge and Mendelssohn could have learned it from any number of writers. Moreover, in the 1699 Spinozismus im Judenthumb, Wachter himself translates contractio infiniti—a standard Latin rendering of the Hebrew tsimtsum—quite differently, namely as ‘Zusammenziehung des Unendlichen’ (Wachter 1699: 85–86). Still, leaving to one side the question of exact sources, and addressing the terminological point alone, it is worth mentioning that ‘Einschränkung’ was the preferred translation by other, slightly later, German thinkers when working in the same cross-field between philosophy and Kabbalah. In both Salomon Maimon’s Lebensgeschichte and in Hegel’s Vorlesungen über die Geschichte der Philosophie, ‘Einschränking’ is the German term employed to translate ‘tsimtsum’.17 And even though no decisive evidence exists, I think it not unlikely that Mendelssohn, too, had the Lurianic Kabbalah in mind when he reformulated Wolff as he did.

Be that as it may, one may wonder what all this has to do with Spinoza. Now, Mendelssohn’s general approach to Spinoza consists in arguing that Leibniz found ‘the form under which Spinoza’s system can exist with reason and religion’ (Mendelssohn 1997: 108). In order to obtain this result with regard to Spinoza’s modal philosophy, he uses the distinction between Urbild and Nachbild to argue that the necessary world described by Spinoza in the Ethics represents, so to speak, half of Leibniz’s doctrine of the best possible world. According to a standard reading of Spinoza at the time which should probably be traced back to Leibniz, Spinoza’s world of necessity is a world in which everything possible has been, is, or becomes, actual (see, e.g., Leibniz 1875–90: 2:562–63; Lærke 2018). And indeed, possibility is not for Spinoza an ontological category of its own, but only a particular way for a finite mind to ignore the causes that always, in reality, determine the existence or non-existence of a thing: ‘a thing is called contingent only because of a defect of our knowledge. … So we call it contingent or possible’ (Spinoza 1986–2015: 1:436 and 546). For Spinoza, then, and contrary to Leibniz, there is no real ontological difference between possibility and real existence: what is conceived as possible by an infinite intellect is identical to what exists. Consequently, Mendelssohn then claims, the way that Spinoza conceives of the actual, real world is comparable to the ideal Urbild of all the possible worlds conceived by God according to Leibniz. Spinoza proceeds as if the Urbild of all the possible worlds was already the existent, actual world, without there being any need for a ‘complement of possibility’. The world is never created outside of God as Nachbild since, for Spinoza, it already exists fully insofar as it is conceived in God’s intellect, as an Urbild prior to any divine decree or act of will, antecedenter ad decretum:

In this way, Mendelssohn contends, by explicating the relation that Spinoza’s doctrine entertains with Leibniz’s, we will better perceive ‘the side of Spinoza’s system that borders on the truth’ (Mendelssohn 1997: 109). The analysis is quite astute. It caters nicely both for Leibniz’s possibilist modal philosophy and for Spinoza’s rejection of possibility as an ontological category distinct from the necessary and the real. What does not sound very Spinozist, however, in particular at a time when Spinoza was routinely assimilated to atheism and materialism, is the idea that ‘the world of Spinoza … is an ideal world,’ existing only in God’s intellect. And yet, Mendelssohn’s assimilation of Spinozism to Leibnizianism on this point has as its basic condition that one does not consider Spinoza to be an atheist and a materialist, but rather to be someone engaged in a vast ‘deification of the world,’ to use Wachter’s expression.

Is it possible to read Spinoza’s text in this way? One obvious objection would be to point to Ethics, part II, prop. 2, according to which ‘extension is an attribute of God, or God is an extended thing’ (Spinoza 1985–2015: 1:449). How can a philosopher who declares God or Nature an ‘extended thing’ be adequately construed as an ‘idealist’? There is only one possible solution to this interpretive problem: One must conceive of Spinoza’s attribute of extension in such a way that it somehow reduces to the ideal, or in such a way that the extra-cogitative and real distinction between the attribute of thought and the attribute of extension is somehow re-conceptualized as an intra-cogitative and conceptual distinction established within the domain of ideas constituting God’s thought and intellect.18 Mendelssohn does not address this question in the Philosophische Gespräche. We do, however, find elements of a solution of this kind in a 1763 letter from Mendelssohn to Lessing.

Let us first set the scene. In the short 1763 text entitled Durch Spinoza ist Leibniz nur auf die Spur der vorherbestimmten Harmonie gekommen, Lessing objected to Mendelssohn’s thesis in the first dialogue, regarding the Spinozist origins of Leibniz’s thesis of pre-established harmony between body and soul. Lessing considered Mendelssohn’s comparison ‘sophistical’ because, says Lessing, on closer inspection, Spinoza’s doctrine of body and soul has only little in common with Leibniz’s pre-established harmony. After all, Lessing argued, in Spinoza we are not dealing with a correspondence between body and soul but with an identity. What Spinoza intended to say in the Ethics was that

In another text from 1763, the Über die Wirklichkeit der Dinge ausser Gott, Lessing took more direct aim at Mendelssohn’s second dialogue, objecting that he, for his part, could ‘form no concept of a reality outside God’ and that any doctrine affirming that things exists as a created Nachbild outside of God, such as Mendelssohn’s depiction of Leibniz, involved a ‘reduplication of the Urbild that was both unnecessary and extravagant’ (Lessing 1970–79: 8:515–16).

Mendelssohn’s replies to these objections in Morgenstunden from 1785 and in An die Freunde Lessings from 1786 are well-known.19 But let us turn to an earlier letter from 1763, written by Mendelssohn to Lessing while the latter was still alive. Here, Mendelssohn offers a phenomenalist analysis of Spinoza that aims at providing a more sophisticated account of Spinoza’s doctrine, taking into account Lessing’s insights. Mendelssohn thus agrees that, for Spinoza, the body is nothing but the object of the soul and that, for this reason, the soul is united with its body in the same way as the soul is united with its own representations:

We here get a much better sense of how Mendelssohn constructs his idealist Spinoza. In response to Lessing’s allegation of sophism, he defends exactly the kind of phenomenalization of Spinoza’s notion of body that will also allow him to reduce the distinction between attributes of thought and extension to a distinction within thought itself. Once this has been established, nothing prevents arguing that all the modifications of all the attributes, including those of extension, together form a purely ‘ideal’ world, or that they constitute something comparable to the ideal Urbild of the world given in God’s intellect before the act of creation according to Leibniz.

What should we think of this interpretation of Spinoza? If we follow Alexander Altman’s classic commentary on the Philosophishe Gespräche, it is simply wrong, to the point where he declares it ‘hard to see Mendelssohn’s justification for trying to approximate the two thinkers’ (Altmann 1966: 19). David Bell and Sylvain Zac describe it as ‘demonstrably inaccurate,’ ‘erroneous,’ ‘incorrect,’ even ‘imaginary’ (Zac 1989: 54–62, 89; Bell 1984: 26). Along similar lines, in a recent study, Detlev Pätzold notes that ‘this is a strange interpretation, indeed, with no support in Spinoza’s texts, nor is there any hint of a proper understanding of his view’ (Pätzold 2011: 118). This may be true from a strictly Spinozist viewpoint although, I must admit, I do not consider the interpretation to be quite that outrageous. It is, however, not at all clear to me that this is a good way to conclude on the matter. First, even if Mendelssohn’s take on Spinoza cannot pass for an acceptable interpretation today, it still is an interpretation that at some point in history was in fact considered perfectly acceptable, for it was clearly deemed so in eighteenth-century Germany. Even those readers of Mendelssohn, like Lessing, who disagreed, did not proclaim the reading impossible, outrageous, or disingenuous in terms comparable to those employed by present-day commentators. Next, it must be stressed that none of the protagonists in these debates nurtured any ambition about providing historically exact accounts of Spinoza’s original intentions. They were appropriating Spinozism for their own ends, trying to search out what they sometimes called ‘the spirit of Spinoza’ which was something quite different from Spinoza himself. In Gott: Einige Gespräche, trying to capture this spirit, Herder even went as far as to claim that Spinoza ‘did not recognize the integral strength of his own system’ (Herder 1940: 123). This given, challenging the exactitude of Mendelssohn’s understanding of Spinozism only makes historical sense if it serves the purpose of subsequently inquiring into the reasons why it was so far removed from Spinoza’s own Spinozism, so to speak. In other words, we must inquire into the transformations in the intellectual landscape that made a reading of Spinoza such as Mendelssohn’s palatable in 1755.

It is in this respect that I think Johann Georg Wachter’s contribution to the history of Spinozism becomes relevant. As we shall see in the next section, it offers an interpretive framework known by most of our German protagonists within which an idealist reading of Spinoza already began to take shape. By contrast, the two other interpretations of Spinoza which otherwise contributed the most the formation of the Spinozabild among German philosophers in the mid-eighteenth century, namely those of Pierre Bayle and Christian Wolff, do not really provide the interpretive resources to explain the idealist direction in which Mendelssohn took Spinoza’s doctrine. In the Dictionnaire historique et critique (1702 edition) Bayle proclaimed Spinoza ‘the first to reduce atheism to a system.’ He identifies Spinoza’s views with those of the Ancient philosopher Strato whom Bayle, following Seneca, described as a thinker diametrically opposed to Plato, because ‘the one [Plato] deprived God of a body, while the other [Strato] deprived him of the soul’ (Bayle 1820: 13:421–23). Given that Spinoza did not admit ‘a real distinction between God and extension generally,’ Bayle argued, he was ‘obliged to recognize that extension and God are the same thing’ (Bayle 1820: 13:439). Consequently, his system ‘reduces [God] the condition of matter, the basest of all beings’ (Bayle 1820: 13:440). It is very hard indeed to conceive of an idealist Spinoza under that interpretation! As for Wolff, his most important analyses of Spinoza figure in the 1723 (1724 on the title page) De Differentia nexus rerum sapientis et fatalis necessitatis—a text mainly focused on denouncing Spinoza as a fatalist—and in his Theologia naturalis, sect. II, chap. IV, sect. 671–716 ([1737] 1741). But neither of those texts suggests that Wolff considered construing Spinoza as an idealist. Instead, in the Theologia naturalis, he echoes Bayle’s judgement when noting that ‘the Ethics of Spinoza is a unique system of atheism’ (Wolff 1741: 730). And he chastises Spinoza for having depicted extension ‘as real,’ himself claiming, against Spinoza, that ‘extension is an appearance, not a reality’ (Wolff 1741: 695). These are not analyses that can serve to depict Spinoza as an idealist who somehow reduces extension to thought. Moreover, in the Differentia, Wolff rejects what he sees as Spinoza’s voluntarism, arguing that, contrary to what he takes to be Spinoza’s view, ‘the essences of things are conceived in the divine intellect before the decree’ (Wolff 1724: 21). But Mendelssohn’s idealist reading of Spinoza in the Philosophische Gespräche is entirely predicated on the notion that Spinoza’s world in fact just is what is conceived in the divine intellect before the decree. Wolff thus flatly denies that Spinoza holds the view attributed to him by Mendelssohn: the one, Wolff, claims that, for Spinoza, there is no world antecedenter ad decretum; the other, Mendelssohn, claims that, in Spinoza, the world antecedenter ad decretum is the only one there is! In sum, Wolff’s texts, as Bayle’s, provide little or no opening for depicting Spinoza as an idealist.21 We will have to look elsewhere if we are to identify a possible source for Mendelssohn’s novel approach. And given his standing in Mendelssohn and in Mendelssohn’s intellectual context, Wachter clearly presents himself as an attractive candidate.

Let us now consider in more detail how Wachter assimilates Spinoza and Kabbalah in the Elucidarius. Wachter offers two principal arguments.

The first is the one most often highlighted in the commentaries, beginning with Johann Jacob Brucker’s critique of Wachter in the Historia critica philosophiae: Wachter transforms Spinoza into a Neo-Platonist by rephrasing Spinoza’s notion of ‘immanence’ in terms of Neo-Platonist ‘emanation’ and, correlatively, by translating the notion of ‘affect’ into that of ‘effect’. These two basic interpretive operations will subsequently allow Wachter to claim that, for Spinoza, ‘modifications’ of God are not properties of God, but consequences or effects that emanate from God (Brucker 1742–44: vol. 4–2, 695 n. f). By means of these maneuvers, Wachter is attempting to acquit Spinoza of the accusation of pantheism22 by creating greater ontological distance between God and the created world while still shunning the doctrine of creatio ex nihilo (Wachter 1706: 53–55).23 If, however, as most commentators do, one approaches Wachter’s book exclusively from the point of view of this first principal thesis, it is difficult to see how it is relevant to the debates among German philosophers in the second half of the eighteenth century. Mendelssohn, for one, explicitly rejected that Spinoza could be read in that fashion when writing in Morgenstunden, alluding to a passage from Saint Paul that Spinoza himself also refers to, that

Indeed, as Winfried Schröder notes, generally within these German debates, the main problem was not whether one should acquit Spinoza of irreligious pantheism or not. It was rather whether pantheism, and Spinozism along with it, was in fact irreligious or not (Schröder 1987: 103–4; Wulf 2012: 263–64). Lessing’s replies to Mendelssohn in Durch Spinoza ist Leibniz nur auf die Spur der vorherbestimmten Harmonie gekommen and in Über die Wirklichkeit der Dinge ausser Gott, the two texts from 1763 already mentioned, clearly testify to this displacement of the problem regarding Christian orthodoxy and pantheism since Wachter’s time. The same goes for the way that Mendelssohn himself approaches the question of Spinozism in Morgenstunden.

Wachter did, however, also pursue a second major argumentative strategy the aim of which was to acquit Spinoza of a possible accusation of materialism and to make his theory of the substantial attributes of thought and extension conform to the kind of Neo-Platonist ontology that Wachter, following Henry More, attributed to the Kabbalists.25 The passage where Wachter develops this argument must be quoted in its entirely, including the footnotes, here in English translation:

The passage concerns the status of matter and extension in Spinoza’s philosophy. Wachter attempts to demonstrate that, in Spinoza, everything that exists is spiritual and that matter is, strictly speaking, nothing. However, in order to circumvent the unequivocal attribution of extension to God in Ethics, II, prop. 2, Wachter maintains that, for Spinoza, extension is different from matter and, in reality, just as spiritual as thought. Consequently, for Spinoza, spirit is the substance of all things and thought and extension are two attributes of this spirit. Wachter relies on three texts.

First, he refers to Letter 73 in Spinoza’s Opera posthuma, that is to say, Letter 83 in most modern editions.30 This is a letter from Spinoza to Tschirnhaus in which Spinoza claims that Descartes has not explained the nature of matter and extension correctly (Spinoza 1985–2015: 2:487).

Second, he refers to the development that Spinoza proposes in the scholium to Ethics, part I, proposition 15. Spinoza here refutes ‘the arguments [he find] authors using, to try to show that corporeal substance is unworthy of the divine nature, and cannot pertain to it’ (Spinoza 1985–2015: 1:422). He explains how ‘we conceive of quantity in two ways, abstractly, or superficially, as we imagine it, or as substance, which is done by the intellect alone’:

Wachter uses this reasoning to claim that Spinoza cannot understand by ‘extension’ what is commonly understood by it, but that he has ‘purged [the term] of its common meaning’ so that it no longer refers to any of the ‘base’ properties habitually associated with it, divisibility, corruptibility, etc. His analysis so far is perfectly faithful to Spinoza’s revisionary approach to the notion of ‘extension’ in the scholium to proposition 15 (Lærke 2014a).

Third, and finally, Wachter must explain why this revised, Spinozist conception of extension as a divine attribute necessarily implies that extension must now be considered spiritual. To make this argument, he turns to the scholium of Ethics, part II, prop. 7, where Spinoza establishes the principles of his so-called ‘parallelism’. In this scholium, Spinoza explains that ‘the thinking substance and the extended substance are one and the same substance’ albeit ‘expressed in two ways’ (Spinoza 1985–2015: 1:451). Wachter considers this, as many commentators after him, to provide sufficient grounds for thinking that the distinction between the attributes is not a real one, but that one eventually reduces to be an aspect the other—in this case, that extension can be reduced to be an aspect of thought.31

On the whole, the interpretation is consistent with the texts by Spinoza that Wachter quotes. Certainly, we must note some terminological ambiguities in the passage from the Elucidarius regarding the use of the terms ‘extension’ and ‘matter’ which does not always correspond to Spinoza’s use. This is because, when reading the passage in context, we realize that Wachter is engaged in a double discussion. On the one hand, as we have seen, he is discussing Spinoza who, according to Wachter, conceives of extension as spiritual and immaterial. He is, however, at the same time in the process of situating himself in relation to a refutation of Kabbalah offered by the Cambridge Platonist Henry More in his 1677 Fundamenta philosophiae sive Cabbalae aëto-paedo- melissaeae. In this text, More discusses how Kabbalists think about matter as a spiritual thing. It is thus not surprising that Wachter’s attempt at combining his interpretation of Spinoza with his discussion of More’s interpretation of Kabbalah occasions some instability in his vocabulary. However, these terminological details only have marginal importance. Wachter’s intentions remain clear. In a nutshell, he argues as follows: First, that Spinoza did not take extension to be the kind of ‘base’ thing that both Descartes and common people take it to be, i.e., passive, divisible matter; second, that what Spinoza refers to by the term ‘extension’ implies such ‘noble’ properties as can only pertain to a spiritual thing, such as indivisibility and infinity. Consequently, what Spinoza understands by the term ‘extension’, is something that must be just as spiritual as thought.

Wachter’s reading did not fall upon deaf ears. It is not unlikely, for example, that Wachter’s idealist approach influenced Leibniz after their encounters at the Berlin Court. In his Considérations sur la doctrine d’un esprit universal unique from 1702, Leibniz thus suggested proximity between Spinozism and the thesis of an anima mundi: ‘Spinoza, who recognizes only one single substance, is not far from the doctrine of a single universal spirit’ (Leibniz 1985: 554; Lærke 2015: 375–83). We find another early appreciation of Wachter’s idealist approach to Spinoza in a text by the English Freemason Andrew Michael Ramsey with the curious name ‘Le Psychomètre’, published in the Mémoires des Trévoux in April 1735. Here, Ramsay argued, explicitly basing himself on Wachter, that ‘those who consider Spinoza a gross materialism do not understand it; it is a pure idealism, consummated Malebranchism, and a kind of exaggerated Jansenism, or fallen into destitution’ (Ramsay 1735; see also Vernière 1954: 402–7).

However, on the evidence I have presented, I think there is some reason to also include Mendelssohn among these authors who appropriated and reframed Wachter’s idealist reading of Spinoza. The spiritualization of the attribute of extension proposed by Wachter is very close to Mendelssohn’s idealist reading in the Philosophische Gespräche. It is even closer to the further explanations he provided in 1763 when replying to Lessing’s Durch Spinoza ist Leibniz nur auf die Spur der vorherbestimmten Harmonie gekommen, as analyzed above in section 3 (see also Schröder 1987: 92, and Wulf 2012: 106). Certainly, at the time, proto-idealist readings of Spinoza were emerging from other quarters as well, often based on associations of Spinoza with Nicolas Malebranche. Most importantly, the 1713–14 correspondence between Malebranche and Jean-Jacques Dortous de Mairan turned on the possible Spinozist implications of Malebranche’s conception of ‘intelligible extension’.32 But this correspondence was not published until 1841 and could not have been known by Mendelssohn (Malebranche 1841). By contrast, given the presence of Wachter’s work in Mendelssohn’s personal library, his confirmed knowledge of the connection between Spinoza and Kabbalah as early as 1755, and his repeated references to that connection and to Wachter himself in later texts as well, it is not unreasonable to suggest that Mendelssohn’s approach to Spinoza in the Philosophische Gespräche was directly informed by Wachter.

Johann Georg Wachter was among the first, if not the first, to interpret Spinoza as a Neo-Platonist. At the same time, he proposed a proto-idealist reading of Spinoza very close to the one later found in Mendelssohn’s Philosophische Gespräche and other related texts. Making the connection between these two readings is not historically unwarranted. The most immediate background for his Spinoza reading, namely the interpretations offered by Bayle and Wolff, can provide some explanation of the shape Mendelssohn’s understanding of Spinoza generally took, but they will not account for its idealism. I cannot, of course, offer a certain demonstration that Mendelssohn took his cue from Wachter. Absent explicit acknowledgments of debt, determining the sources of any philosopher’s views is always an elusive affair. Still, I think there is quite a lot of circumstantial evidence pulling in that direction. Mendelssohn was familiar with Wachter’s work and adopted his general thesis regarding the proximity between Spinoza and Kabbalah. He did so explicitly in the mid-1780s in his correspondence with Elise Reimarus and again in Morgenstunden. And if we are to trust the testimony of Friedrich Nicolai—and I see no good reason that we should not—he also did so in 1755 already when writing the Philosophische Gespräche. There is considerable biographical room for making reasonable conjectures about Wachter as a significant source for Mendelssohn’s reading of Spinoza.

Mendelssohn did not, however, simply draw on Wachter’s reading. In another perhaps more diffuse sense, one could also say that his original reading of Spinoza in the Philosophische Gespräche had Wachter’s work as its historical condition. In his reading, Mendelssohn presupposed the possibility of spiritualizing extension and making the distinction between attribute an intra-cogitative one. This was arguably contrary to Spinoza’s own original intentions. It was also contrary to a longstanding tradition of reading Spinoza as a kind of atheist or materialist. Mendelssohn himself offered very little in terms of justifying this controversial idealist premise. And yet, with this reading, Mendelssohn managed to set the tone for much subsequent discussion. Whether they agreed with it or not, Mendelssohn’s contemporaries did not dismiss his idealist reading out of hand. And this in itself suggests that someone had already prepared the terrain for such a reading. And what I have proposed here as an intriguing option is that this ‘someone’ was likely Johann Georg Wachter, whose argument in favor of Spinoza in the Elucidarius cabalisticus was thus, in some sense, the mother of all idealist readings of Spinoza.