F.A. Trendelenburg and the Neglected Alternative Andy Specht In his landmark study of neo-Kantianism, Klaus Köhnke begins by telling us that in the history of nineteenth century philosophy, 'es gibt einen großen Unbekannten' ['there is a great unknown'] (Köhnke, Neukantianismus, 23). This unknown is Friedrich Adolf Trendelenburg, the philosopher who was a direct influence on Franz Brentano, Hermann Cohen, Wilhelm Dilthey, Rudolf Eucken, and even Søren Kierkegaard. However in light of recent work, including Köhnke's, Trendelenburg has begun to reemerge as a great figure in nineteenth century philosophy.1 Among Kant scholars, Trendelenburg has always been remembered for his feud with Kuno Fischer over the subjectivity of space and time in Kant's philosophy. This surprisingly acrimonious feud generated works with titles like 'Anti-Trendelenburg', and the issues involved in the dispute were taken up and further considered by the newly forming neo-Kantian movements. The topic of the dispute, now most commonly referred to as the 'Neglected Alternative' objection, has become a prominent issue in contemporary discussions and interpretations of Kant's view of space and time.2 Roughly, the Neglected Alternative contends that Kant unjustifiably moves from the claim that we have a priori intuitions of space and time to what should be viewed as a sceptical conclusion – that space and time are only features of human sensibility and have nothing whatsoever to do with any subject-independent things in themselves. Most current discussions trace the objection back to Trendelenburg and often use him to motivate the objection.3 However, to date 1 In addition to Köhnke's neo-Kantianism book, see Hartung and Köhnke, eds. Friedrich Adolf Trendelenburgs Wirkung and Beiser, Late German Idealism. 2 Henry Allison revived the debate over the objection with his article 'The Non-Spatiality of Things in Themselves for Kant'. The debate shows no sign of letting up; since 2007 alone, there have been at least three articles providing new defences of Kant against the Neglected Alternative and two articles reinforcing the Neglected Alternative against Kant. In favour of Kant, see Graham Bird's 'Trendelenburg, Fischer and Kant', Desmond Hogan's 'Three Kinds of Rationalism', and Tobias Rosefeldt's 'Subject-Dependence and Trendelenburg's Gap'. In support of the Neglected Alternative objection, see Peter Herissone-Kelly's 'The Transcendental Ideality of Space and the Neglected Alternative' and Edward Kanterian's 'Trendelenburg Versus Kant, Fischer and Bird'. 3 The objection ultimately originates in the early reception to the Critical philosophy in the 1780s. Of the philosophers in this time period, H.A. Pistorius developed the most thorough formulation 1 Trendelenburg's actual arguments and his reasons for rejecting the Kantian view of space and time have not been sufficiently uncovered; my goal here is to fill this lacuna. This task is primarily exegetical, but it involves compiling and synthesizing Trendelenburg's arguments across his corpus. I hope that this in turn accomplishes two specific goals. First, by better understanding what Trendelenburg, who more than any other philosopher has developed and advocated the Neglected Alternative, actually argued, we will be in a better position to assess whether the Neglected Alternative objection against Kant is successful. But in addition, Trendelenburg's own system is of independent philosophical interest, and my work here will shed light on one part of it. In the first section, I will begin by presenting Trendelenburg's Neglected Alternative objection, as it is formulated in his Logische Untersuchungen, and in the second section we will then briefly discuss some of Kuno Fischer's criticisms of Trendelenburg's objection. In the third section, we will look beyond the Logische Untersuchungen to further refine Trendelenburg's objection; ultimately we will develop two possible interpretations of the objection. In the fourth section, we will very briefly look back to the Critique of Pure Reason for a preliminary assessment of the extent to which Trendelenburg's objection succeeds in finding a target. In the fifth section, we will wrap up various issues surrounding our understanding of the alternative view of space that Trendelenburg endorses. The final evaluation of whether Trendelenburg's objections to Kant are successful will remain for future work. I. The Logische Untersuchungen: Trendelenburg's First Formulation of the Neglected Alternative Trendelenburg's philosophical system is laid out in his two volume Logische Untersuchungen. Originally published as a nearly 700 page tome in 1840, it was revised and expanded in 1862 and 1870, eventually reaching over 900 pages. In this work, Trendelenburg endeavours to create a system of 'fundamental philosophy', or a 'foundational science', which would of the Neglected Alternative in his various reviews. See especially his 'Erläuterung über...' 2 provide a basis for all particular sciences (Logische Untersuchungen (Vol. 1, 1862), 14).4 It is important to emphasize, however, that although Trendelenburg's goal is to unify and find a foundation for the sciences, he has no intention of rebuilding them from the ground up or revising them in any significant way. He takes particular sciences as giving us secure results, and the task of philosophy is to find the underlying logic and metaphysics of these sciences, resolve disputes between the sciences, and ultimately show how they are unified (see Beiser, Late German Idealism, 28-31 and Köhnke, Neukantianismus, 35-8). Trendelenburg further holds that knowledge is only possible through the unification of thought and being; this conception of knowledge expresses the idea that knowledge is about the world that exists independently of our minds, but for the mind to grasp this world, there must be some common element found in both mind and world. Especially in light of the organic world view that he goes on to develop, Trendelenburg's philosophy echoes Schelling's dictum that 'Nature should be mind made visible, mind the invisible nature' (Ideen zu einer Philosophie der Natur, 56). Accordingly, the central task of Trendelenburg's system is to explain how in general the unification of thought and being can occur (LU, 11-12; 135-6.). In the second and third chapters of his Logische Untersuchungen, Trendelenburg discusses two methods that he argues have been failures at grounding foundational science. The first method is what Trendelenburg calls 'pure formal logic', and the second method is the dialectical method. He describes formal logic as 'want[ing] to grasp the forms of thought in and for themselves, without inspecting the content in which these forms appear. It wants to understand the concept, the judgement, and the inference based alone on the activity of thought as it relates to itself' (LU, 16). Trendelenburg explicitly identifies himself as primarily engaging with two philosophers, who advocate formal logic: August Twesten, a follower of Schleiermacher, and Moritz Wilhelm Drobisch, a follower of Johann Herbart.5 The upshot for Trendelenburg is that the systems of formal 4 Hereafter, I will abbreviate references to this work with 'LU, page number'. I cite the 1862 edition, since it is the one that sparked the dispute over the Neglected Alternative and the additions in the 1870 edition do not concern the issues we will discuss. All translations of German texts (excepting Kant) are my own. On Kant texts and translations, see note 9. 5 Herbart himself appears in the Logische Untersuchungen as an essential philosopher for 3 logic presented by these philosophers do not provide an adequate basis for first philosophy, because they raise metaphysical questions that they do not provide the resources to address and that must be addressed by first philosophy (LU, 35). For example, they rely on the concept of negation but do not provide an adequate explanation of what negation really is. More generally, philosophical systems of formal logic lack the resources to investigate the origins of their concepts (LU, 24-6). Thus, formal logic must either be abandoned or supplemented, if we are to establish a system of first philosophy (see Risto Vilkko's 'Trendelenburgs Kritik der Herbartschen Logik' and Stephan Käufer, 'Hegel to Frege', 270-77). In the next chapter, which spans nearly a hundred pages in the second edition, Trendelenburg argues that dialectic cannot provide an appropriate foundation for philosophy either. His primary target is Hegel himself, though he also critiques a number of other Hegelians in some detail. The most notorious of these criticisms is the harsh line by line refutation of Kuno Fischer's dialectic, added in the second edition, which was the main catalyst of the Streit between Fischer and Trendelenburg that will be discussed shortly. One important thread in his criticism of dialectic is that the sorts of progressions through concepts like 'Being', 'Negation', and 'Becoming', which are endorsed as presuppositionless by the dialectical philosophers, have at least one important presupposition: the existence of motion (see Hans-Jürgen Lachmann's 'Über den Anfang der Logik und die Logik des Anfangs'). After rejecting both formal logic and dialectic, Trendelenburg goes on to hypothesize that motion [Bewegung] is the fundamental force that unites thought and being, and he therefore makes motion the starting point of his philosophy.6 Trendelenburg develops his view of motion in the remainder of the first volume of the Logische Untersuchungen, and in the second volume the teleological side of motion is elucidated. Trendelenburg. At the beginning of the work, Trendelenburg characterizes his system as tracing a path through the Hegelian and Herbartian schools (vii). It is also noteworthy that Trendelenburg devotes far more pages in the Logische Untersuchungen to discussing Herbart's view of space and time than he spends discussing Kant's view. 6 See especially LU, 136-40, where Trendelenburg argues that an action or activity (Thätigkeit) must be what unites thought and being and LU, 141-54 for the argument that this unifying activity is motion. 4 On Trendelenburg's view, motion exists both in the human mind and in mind-independent reality. Trendelenburg argues for a dynamical view of space and time, where space and time are not considered to be finished products but are instead generated by motion.7 The result is that since motion exists both in the human mind and outside of it, motion generates space and time, both as ideal in the human mind through constructive motion and as real through the motion that exists independently of the human mind in reality. Trendelenburg realizes that this straightforwardly contradicts the transcendental idealism founded by Kant and endorsed by many nineteenth century German philosophers. According to transcendental idealism, space and time only have validity for representations of the human subject and have absolutely nothing to do with anything that exists completely independently of human cognition. If Trendelenburg's view of space is accurate, then it is essential that he persuade his reader that transcendental idealism is inaccurate. Trendelenburg's primary attack on transcendental idealism will be the Neglected Alternative objection; he will try to show that Kant's arguments concerning space and time in the Transcendental Aesthetic of the Critique of Pure Reason do not entail transcendental idealism and are ultimately consistent with his own view on which space and time are both subjective and objective.8 However, before looking at Trendelenburg's Neglected Alternative objection, we should consider what exactly Trendelenburg finds objectionable about transcendental idealism – why is he so motivated to develop an alternative view in the first place? The answer is that Trendelenburg believes that transcendental idealism destroys the certainty and necessity of the sciences. This point is most clearly made in a passage where he discusses Kant's philosophy of geometry: 7 He argues further that even if space and time were finished products, motion would be required to give unity to each of them (LU, 149). 8 Trendelenburg also objects to Kant's seemingly insufficient and conflicting view of motion. It is insufficient, because Kant fails to show how it is that the a priori intuitions of space and time come together and create motion. But Kant ultimately descends into inconsistency, because in the Aesthetic, he is adamant that motion presupposes space and time, but in the Deduction he seems to reverse course and argue that motion (in the form of synthesis) underlies our experience of space (LU, 165-6). 5 The Kantian view has been credited for grasping the necessity of geometry that arises from the pure form of intuition as an a priori science. If the certainty of geometry rests on this backing, then it depends on the subject; and if one accepts space as a given form, then this contingently given thing [zufällige Gabe] can at some point alter; and nothing contradicts the possibility that other intuiters have other forms; perhaps a space with two or four dimensions is that most beloved to the gods (LU, 160). Immediately after these points, Trendelenburg asserts that the Kantian philosophy makes mathematics and physics subjective, because they become 'nothing but fantasies of our particular intuition' (LU, 160). There are hints of at least two objections in this passage from Trendelenburg. The first objection is that Kant's conception of space is consistent with the possibility of other beings having other forms of intuition, including more sophisticated beings perceiving outer objects in radically different spaces. This sort of relativism about space undermines the necessity and universality of geometry, which becomes just the science of our particular kind of space. However, this objection is one to which I think Kant has plausible responses readily available. Kant admits the possibility of other beings with non-spatiotemporal forms of intuition but denies that this in any way poses a problem for his philosophy.9 The laws of geometry are laws that concern our form of intuition and are necessary for all human cognizers. In other beings, there may be other forms of intuition and even other forms that order outer objects, but this does not undermine the universality and necessity of geometry. Geometry is universal in that it describes the form in which all humans must experience outer objects. It provides necessary truths because it describes a structure that is an a 9 He raises this possibility in the Transcendental Aesthetic when he says that “we cannot judge at all whether the intuitions of other thinking beings are bound to the same conditions that limit our intuition and that are universally valid for us” (A27/B43; see also B72). In addition, the infinite being, God, certainly does not intuit objects in space and time. (Note: I follow the Guyer and Wood translation of the Critique of Pure Reason and employ the standard A/B convention for citing the first and second editions of the Critique, respectively). 6 priori and necessary condition for human experience.10 But there is another objection suggested in the passage that Kant should find more troubling. It comes from Trendelenburg’s claim that on the Kantian view, space depends on the subject, and therefore space is a 'contingently given thing' that 'can at some point alter'. The objection seems to be that by grounding geometrical truths in the human subject, which is something contingent, the necessity of geometrical truths is undermined. There is no guarantee that our constitution could never alter in such a way that we no longer intuit objects in a space with a Euclidean structure; perhaps we could start intuiting outer objects in a two or four dimensional space, or a non- Euclidean space. If this were to occur, then at least some propositions of Euclidean geometry would be false.11 Thus, Kant's account of the source of geometry undermines the necessity of geometry. When it comes to responding to this objection, Kant has tied his own hands. In reply, he can point out that he has demonstrated that space is an a priori condition for our experience, but he has not demonstrated that it is impossible for a form of intuition (specifically, space) to change or be replaced with another form of intuition. Granted, this change would result in a different kind of experience, but Kant also cannot eliminate the possibility of no longer having the kind of experience in which our form of intuition, space, is essential and instead having a kind in which a different form of intuition is essential. Kant cannot eliminate such a possibility, because for him, claims about the ultimate nature of the subject are off-limits, i.e. he cannot make claims about what the subject in itself must be like (see, for example, A278/B334). Kant acknowledges that the nature of our sensibility has a cause in the world of things in themselves, but we cannot know anything 10 To put this in the terms of contemporary philosophy, in which necessary truths are usually considered to hold without condition, we can view Kant as holding that geometry has conditional necessity, where the condition is the constitution of human sensibility (cf. Falkenstein, Kant's Intuitionism, 267-8). 11 That space has a Euclidean structure in particular is not essential to this discussion. What is essential is that geometry is about the structure of space (whatever it may be) and these truths about space are necessary. Kant holds that space has a Euclidean structure, and this is not a point of contention between Kant and Trendelenburg. Thus, I will specifically talk about Euclidean geometry when I need to clarify that I am talking about the laws that govern the actual space grounded in our a priori intuition. 7 about it, much less its modal properties. Thus, there is no way of ruling out that we, as the transcendentally real subjects who underlie our forms of intuition, could someday alter our forms of intuition in a way that falsifies Euclidean geometry. I think, here, Trendelenburg identifies a significant problem for Kant's view of the sciences. According to both Kant and Trendelenburg, the sciences are supposed to be necessarily true, but Kant's grounding of necessity ends up undermining their necessity. Though Trendelenburg was the first to articulate this issue, very similar objections appeared in attacks on the Kantian philosophy by Bertrand Russell and G.E. Moore in the twentieth century.12 Trendelenburg's system in the Logische Untersuchungen is in part an attempt to provide a foundation for the sciences that is stronger than what Kant is able to give them and this entails bringing the subject-matter of the sciences out of the subject and into mind-independent reality.13 Accordingly, Trendelenburg views Kant's characterization of space as something pertaining entirely to the human subject as a sceptical result. He identifies a deep urge to know the thing in itself and says that 'it is the tense nerve [spannende Nerv] in all cognition that we want to reach the thing, as it is; we want the thing, not ourselves' (LU, 161-2). However, if space and time are just products of the self, then we are trapped in the representations of our own minds. This is where Trendelenburg states the Neglected Alternative objection for the first time. He returns to Kant's Metaphysical Expositions and considers them in order. For each Exposition, he argues that it does not warrant the conclusion that space is exclusively subjective. For example, he looks at the first Exposition and concedes that space and time exist in us a priori antecedent to experience, but in 12 See Bertrand Russell, The Problems of Philosophy, chapter VIII and G.E. Moore, Some Main Problems of Philosophy, 154. The objections from Russell and Moore (though not Trendelenburg) are discussed in James Van Cleve, Problems from Kant, 37-43. Falkenstein independently considers this kind of objection in his Kant's Intuitionism, 267-8. 13 In the same section, Trendelenburg presents another challenge to transcendental idealism that directly targets its coherence. He argues that if things in themselves appear to us in space and time, then there must be something in the nature of things in themselves that makes this interaction possible and a fortiori this aspect of things in themselves must be spatiotemporal (LU, 161). Thus, Kant cannot coherently hold that objects appear to us in space and time without holding that things in themselves are spatiotemporal. 8 Kant's proof of this 'there nowhere emerges a thought that prevents space and time from being at the same time something outside of human intuition. This exclusive “only” in the claim that space and time are only subjective is not justified' (LU, 162). The stories are similar with the other Expositions; after discussing the second Exposition he acknowledges that it shows that space and time are subjective, but he asks 'what prevents them from being objective at the same time?' (LU, 162). After reviewing all of the Expositions, he gives the classic statement of the Neglected Alternative: Even if we accept the arguments that demonstrate that space and time are subjective conditions, which precede perception and experience in us, there is still not a hint of a proof that they could not at the same time be objective forms as well (LU, 163).14 The neglected hypothesis is that space could have something of a dual-nature. It could exist both as an a priori intuition in our minds and as an 'objective form' - a structure that orders the things in themselves, the objects that exist outside of us and independently of us. In addition, Kant's argument not only fails to rule out this possibility, but Kant 'hardly thought of the possibility' (LU, 163). Though this hypothesis is intriguing, it is clearly in need of more development, and Trendelenburg tells us a little bit more about it in the Logische Untersuchungen. After reiterating his conception of knowledge as uniting thought and being, this time in terms of a 'harmony' between the two, he says that Kant rules out the possibility of an agreement between space and the things in themselves (LU, 163).15 However, Trendelenburg quickly turns his attention to other issues in 14 This quotation is also translated in M.J. Scott-Taggart, 'Recent Work on the Philosophy of Kant', 184 and has been reprinted in various recent articles on the Neglected Alternative. 15 In this context, Trendelenburg usually just uses the term 'the things' [die Dinge] rather than the Kantian 'things in themselves' [Dinge an sich] to refer to the objects that exist absolutely independently of ourselves. Here, I keep with the Kantian terminology in describing Trendelenburg's view. Cf. Kuno Fischer, Kants Vernunftkritik und deren Entstehung, vi and C. Grapengiesser, Kant's Lehre von Raum und Zeit, 68. See also LU, 340 for further discussion of 9 Kant's view of space and time, like the nature of motion and the problems concerning the infinitude of space and time. This leaves us with at least a couple unanswered exegetical questions: how does Trendelenburg understand the terms 'subjective' and 'objective'? What sort of agreement does Trendelenburg think there may be between space and time and things in themselves? We will have to investigate other sections of the Logische Untersuchungen and his subsequent texts for answers. Still, for our purposes, Trendelenburg has made the crucial claim: that there is a logical gap in Kant's argument; specifically, it fails to rule out the alternative that Trendelenburg describes. II. Kuno Fischer's Counter-attack Trendelenburg surely did not anticipate it, but his discussion of the Neglected Alternative in the Logische Untersuchungen ended up being just the first salvo in a long battle over this objection. Trendelenburg's criticisms of Kant's view of space, which were all present in the first (1840) edition of the Logische Untersuchungen, received scant attention until 1865, a few years after the publication of the second edition of this work.16 This is the year that Kuno Fischer published his System der Logik und Metaphysik.17 Fischer counters the attacks from Trendelenburg by devoting a section to an overview and critical evaluation of Trendelenburg's philosophy, specifically his view of motion and his criticisms of the Kantian view of space and time. The same philosopher whom Trendelenburg belittled as finding contradictions in concepts due to contradictions in his own mind (LU, 124) would ultimately lure Trendelenburg into a prolonged debate over the accuracy of his Neglected Alternative objection. 'thing'. 16 This is not to say that the first edition of the Logische Untersuchungen as a whole was ignored. According to Klaus Köhnke, Trendelenburg's criticisms of Hegelianism were widely considered to be successful (Neukantianismus, 56). For further evidence, see the references in Beiser, Late German Idealism, 59n. See also George Morris, 'Vera on Trendelenburg', 93 for the claim that Trendelenburg was the philosopher most responsible for the diminution of Hegel's logic. 17 An updated version of his earlier Logik und Metaphysik oder Wissenschaftslehre, the work Trendelenburg criticizes in his second edition of the Logische Untersuchungen. 10