Any work on Kant’s theoretical philosophy must orient itself within a set of problems that has been developed in a steady stream of literature starting with the initial reviews of the Critique of Pure Reason in the 1780s. There are many ways to phrase the perennial questions that swirl around both the pre-Critical and Critical metaphysics. My foci are on the debates about realism and idealism, the nature of space and time, and the distinction between things-in-themselves and appearances. While the present work concentrates on Kant’s early works up to and including the 1770 Dissertation, the interpretation that it provides of Kant’s metaphysics prior to the Critique of Pure Reason has implications for how we interpret that work as well. In order to justify a detailed study of Kant’s early thought, which many might dismiss as superseded by and irrelevant to the mature works, I want to illustrate, in the clearest terms as possible, how this present work can be situated within the major trends within Kant scholarship.
Philosophy in the twentieth and twenty-first centuries can be characterized by, among other things, the rejection of metaphysical dualisms of any sort. That trend has deeply informed the research into Kant’s writings, which has been a remarkable hotbed of activity and has cross-fertilized a host of topics in Anglo-American philosophy. Out of that prodigious activity, a division between two approaches to Kant’s potential metaphysical dualism has emerged. The first approach shows how Kant speaks to anti-metaphysical research projects in epistemology, the philosophy of mind, the philosophy of science, the philosophy of psychology, and the philosophy of language. This approach is championed by scholars like Henry Allison (2004), who look to defend such an anti-metaphysical approach as a correct historical reading of Kant, as well those such as Abela (2002) and Hanna (2001), who follow in the footsteps of Wilfrid Sellars by using Kant to construct contemporary theories of cognition, perception, and reference. The second approach follows the tradition of Strawson (1966) and does not attempt to tame the metaphysical dualism within Kant’s writings. Instead, it tends to focus on its failures, ambiguities, contradictions, and the general implausibility of some of its core ideas. Instances of this approach are found in Westphal (2004) and Van Cleve (1999), although some have argued that such dualism is not as disastrous as it seems (Langton 1998). These divisions straddle a further distinction between rationalist reconstructionism or “appropriationism” versus a more historical “contextualism” (Mercer 2019). The debate between metaphysical versus anti-metaphysical (cognitive or epistemological) approaches has the field divided, and it is not clear that either interpretative method can mediate the dispute. Ultimately, the ambiguity within Kant’s texts, which allows them to sustain this division, demands a hermeneutical approach that goes beyond mere historical contextualism. Some anachronisms are inevitable. There are at least two significant reasons for this.
Firstly, if scholars make no effort to translate Kant’s language and ideas into accessible concepts outside of his specialized terminology, then contextualist research, whether attempting to avoid or accept metaphysical dualism, remains of interest only to a few well-trained Kantian scholars. Kant’s texts and ideas will remain wrapped in an opaque argot. Explanations of obscure concepts will rely on other equally obscure notions resulting in an empty and alienating edifice. A sort of scholasticism emerges, which can of course be said of a great amount of scholarly output in any field, but which appears to outsiders to be little more than a debate about the number of angels that can fit on the head of a pin.1 It is telling that Kant’s notion of an “architectonic” has become synonymous with this for some. The second barrier to simple contextualism is that Kant himself seems to have been a less-than-careful reader of other thinkers. Geographically isolated and hampered by his health, his correspondence pales in comparison to most other major philosophers of the time. His references to and explicit readings of the work of others are minimal. While contextualism in Kant scholarship is certainly in full swing as more and more scholarship appears on German thinkers that may have influenced Kant or that were contemporaries with him, it is not clear to me that this has moved the needle in terms of our ability to solve longstanding interpretive disputes. This lack of progress has less to do with the excellent scholarship on “minor figures” (according to the mainstream philosophical canon) and more to do with the idiosyncrasies of Kant’s language and ideas. Kant seems to have rarely stepped into another’s philosophical system without distorting it. His influences and contemporaries offer us only more complications to an already complicated, jargon-heavy system. Strangely, Kant’s own early works are rarely read as a helpful guide to his transcendental idealism. I think that this is a mistake for which Kant himself is partially responsible as he notoriously disowned his earlier writings.
Kant’s thought is dominated, in my view, by a metaphysical vision that has been called a “two-world ” metaphysics, which I take to mean a dualistic vision of two spheres of being, which lack any shared objects or forms, although it is not impossible that there is some connection between them. Allais describes it as follows: “The traditional ‘two world’ camp sees Kant’s appearances and his things as they are in themselves as different kinds of entities that are in some kind of (unknown) relation to each other, and is generally committed to understanding appearances in terms of phenomenalism, as mental or virtual entities” (Allais 2004, p. 657). So-called one world views convert this distinction into one between two types of properties (Langton 1998, p. 13) or aspects (Allison 2004, p. 16) that belong to the same object. Immediately, I should note that I deny that the two-worlds interpretation is committed to phenomenalism or to understanding appearances as intentional, virtual, or mental objects (e.g. Van Cleve 1999, pp. 8–9). Nor did the pre-Critical Kant think that this relation was unknown, even if it could not be made fully and determinately understood. Of course, the fundamental issue in the study of Kant’s theoretical philosophy is not whether he held such a two-world metaphysics between the years that are my focus (1747–1770). After all, the pre-Critical works are largely ignored and most who have an opinion about them assume that they contain objectionable metaphysics of some sort. Most scholars are concerned with whether he held a two-worlds ontology in the Critique of Pure Reason.
While I generally do not discuss works after the 1770 Dissertation, I do give some reasons to think that this ontology may remain in some form in the Critical era. In particular, I hold that the fundamental assumption that leads scholars to agree that a two-worlds commitment to things-in-themselves renders observable reality less than real, illusory, mental, or imaginary is a mistake.2 A two-worlds metaphysics must resist any connection between worlds that threatens to reduce one to the other or eliminate one as imaginary, for that would be, by definition, a one-world view. But critics of two-world views are convinced that the undeniable subject-dependence of the notion of appearances inevitably collapses into a noumenalistic one-world view if any substantial two-world distinction is allowed. In other words, to allow a two-worlds distinction turns the world we experience into a subjective projection atop an unexperienced and, thus, unknown reality. This must be the case, they reason, because Kant’s theory of space and time is tied to the mental operations that the human mind performs in perception to represent the world. Given that space and time are said to be a priori forms of intuition, what else then could a two-worlds view mean except that the subjective world of appearances is a mental construction? My sense is that such a threat of phenomenalist falsification of empirical reality is a problem for both one-world and two-world theories as long as space and time are something like mental-perceptual schema. This internalization of space and time makes it difficult for every sort of interpretation to resist the idea that Kant’s ontology gives a fundamental status to things-in-themselves and degrades the sensible world to the mental. By showing that this internalist interpretation of the Critical theory of space and time is mistaken, I open the door to the possibility that the phenomenalist threat of a two-worlds metaphysics can be eliminated. To demonstrate the precise nature of his metaphysical commitments in Critique of Pure Reason is a task for the sequel to the present work. By exploring a non-phenomenalist two-worlds metaphysics in the pre-Critical works, the groundwork will have been lain for extending that view, with appropriate modifications, to the mature works.
A two-world metaphysics is not committed to phenomenalism. The phenomenalist thinks of appearances as mental entities rather than the empirically real objects of experience. The lack of ontological reduction on a two-worlds view is clearly seen in the pre-Critical period, where it is less controversial (but not entirely without controversy) to say that Kant held such a view. During this time, he never believed that phenomenalism or ontological reductionism was the implication of such a metaphysics. While Leibniz himself was often charged with such phenomenalism, the early works can be seen as a sort of “apology for Leibniz,” and his two-worlds division between the Kingdoms of Nature and the Kingdoms of Grace, as Kant even says of his own Critique of Pure Reason (ÜE, AA 8:250). Kant’s life-long project in metaphysics was to show that phenomenalism was not the result of metaphysics: one could maintain a commitment to the reality and truth of the two separate domains of physics and metaphysics without one collapsing into the other. The fact that this is not recognized and, in fact, quite the opposite aim is regularly attributed to him, is puzzling but not without explanation.
There are (at least) two mistakes—one regarding the pre-Critical writings and one regarding the Critical writings—that are at work here. Both mistakes are the heritage of rational reconstructionism with its ambition to make Kant’s thought speak to our modern anti-metaphysical and anti-dualistic worldview. In the dominant interpretations of the pre-Critical philosophy by leading English-language scholars (Laywine 1993; Schönfeld 2000; Kanterian 2018), it is largely ignored that Kant accepted the Leibnizian conception of substances as living, mind-like beings, whose interconnection with each other, via the creative power of God’s divine intellect, gives rise to the harmonious material order of nature. Even in works of remarkable insight on Kant’s philosophy of nature (e.g. Friedman 1992; Watkins 2005), it is commonly held that Kant’s pre-Critical metaphysics is simply an account of “composite corporeal substances,” with a “monistic conception of substantial force” in which everything is explained via “the same agency of transuent causation or physical influence” (Edwards 2000, pp. 74–8). The baroque, dualistic metaphysics that I will show that Kant held, which tends toward pre-established harmony , is so far outside the realm of plausibility for most philosophers that I suspect that it is a mixture of both of the principle of charity and a desire to show the contemporary value of Kant’s thinking that...