1 Introduction

In Sect. 2 of this paper, I argue that the assertion of a priori indexical statements, such as “I am here now” and “I exist”, although necessarily spoken by the designated “I” of the context in which they are spoken, are not specifically a priori with respect to that “I”. Such statements do not reflect self awareness on behalf of the speaker, but an awareness by an understanding that is independent of the a posteriori spatiotemporal context to which the speaker belongs.

In Sect. 3, I employ McTaggart’s paper on The Unreality of Time to highlight this issue in the context of the temporal indexical, “now”. The scenario is extended, in Sect. 4, to the spatial indexical of “here”, despite McTaggart’s argument to the contrary. The focus of Sect. 4, however, is the use of Kant’s definition of the forms of inner sense and outer sense to explain why we have a sense of the “here” and “now” in spite of the unreality of space and time.

In Sect. 5, I expand upon this proposal to encompass Kant’s versions of the self. In Sect. 6, I attend to concerns raised against Kant’s ideality of time and space, firstly by Kant’s peers, Lambert and Mendelssohn, on whether spatiotemporal properties can be classified as no more than appearances if they are properties of the mind, and secondly, as an extension to these concerns most recently highlighted by Falkenstein and Brook, on the Problem of Localisation. In Sect. 7, these concerns are addressed by drawing on the full implications of Kant’s transcendental idealism that removes the properties of time and space not only from things that exist externally to the mind but also from mental representations insofar as mental representations exist in themselves.

In conclusion, I defend the resulting idealism against prospective charges of epistemological scepticism.

2 The Problem of Direct Acquaintance with the “I”

The accidents of realityFootnote 1 are particularly acute when presented through the lens of pure indexicals, such as “I”, “here”, and “now”. If you consider yourself as the pure indexical, “I”, standing independently of the circumstance in which you find yourself, then the circumstance in which you find yourself is somewhat arbitrary. It may be that you are a plumber, or a dentist, that you are living in Chicago, Illinois, or Kaliningrad, Russia, perhaps reading this paper in 2022, or in 2032. These facts seem arbitrarily designated when considered in terms of the indexicals that relate directly to the subject.

It is a given, of course, that you are who you are, where you are and when you are. But on the question of whether you are Joanna O’Toole, a plumber living in Chicago in 2022 or whether you are Polina Medvedev, a dentist living in Kaliningrad in 2032, this depends upon your state of affairs. Following David Kapan (Kaplan, 1989), we say that the specific content of indexicals is determined by the context in which they are expressed. However, in accordance with Kaplan, the content does not confer the cognitive significance of the use of indexicals within a statement. The statement, “I am a plumber and today I have a leaking bath tap to attend to” presents a far greater sense of responsibility to the speaker than “Joanna O’Toole is a plumber and on January 8, 2022, has a leaking bath tap to attend to.” Even if the speaker is Joanna O’Toole, and she is aware that she is Joanna O’Toole, she may not be aware that today is indeed January 8, 2022.

By Kaplan’s definition, the cognitive significance of indexicals is built into their character, that is, the meaning that holds regardless of the context. It is the character of indexicals that offers a direct reference from the agent of the context, as Kaplan calls the speaker, to, as in the example of “I”, the agent herself, or, as in the case of “here”, the place in which the utterance occurs, or, as in the case of “now”, the time at which it occurs. Kaplan demonstrates that the character of an indexical bears epistemological value beyond the semantic content that it denotes, drawing on the scenario in which “A kidnapped heiress, locked in the trunk of a car, knowing neither the time nor where she is, may think ‘It is quiet here now’ and the indexicals will remain directly referential.” The heiress is not able to locate the content of the indexicals, “here” and “now”, yet she is sufficiently informed to state that “It is quiet here now”. This leads us to Kaplan’s a priori, though contingent, judgments. The statement, “I am here now”, is, to Kaplan, a priori as it is logically undeniable purely due to the character of the statement. However, it still remains contingent as the location and time at which this statement is uttered depends upon the context of its utterance.Footnote 2.

It is important to note that the a prioricity of statements, such as “I am here now” and “I exist,” is not derived from a privileged cognitive insight on behalf of the agent. Kaplan is mindful to instruct against the conflation of indexical direct reference with the cognitive receptivity associated with Bertrand Russell’s direct acquaintance. From this it may be understood that the a prioricity of statements that employ indexicals is carried by the logical relationship between the speech act, as thought or as uttered by the agent of the context, and the contents of the context. The statement, “I am here now”, bears a logically valid relationship to the context in which it is spoken by the agent at the place and time at which it is spoken. This is a functional relationship drawn from the objective assessment of the context. It is not a relationship encapsulated within the state of mind of the agent. In this respect, the heiress has no greater or lesser a priori apprehension as she thinks to herself, “I am here now”, than you or I do in our reflection upon the prospect of an heiress, locked in the trunk of the car, thinking, “I am here now.”

It may seem odd that the epistemological standing of statements are not specifically held by the agent of the context but only held in view of the scenario of the statement being uttered or thought by an agent. Indeed, it would seem natural to assign the a priori knowledge of statements, particularly involving indexicals, to those wearing the shoes of those who utter such statements. The question is begged, can the cognitive significance of the indexical reference made by the heiress be shared by the objective observer? The answer is, well yes, of course, for, in our appreciation of her plight, we may well reflect that there, but for the grace of God, go I. Nonetheless, there remains a niggling sense that we ought to assign the cognitive significance of an indexical expression to the cognitive faculty of the agent, for why else would Kaplan use the term, “cognitive significance”, rather than, say, “contextual sensitivity” in reference to the semantics of pure indexicals? It is hard to avoid the idea that the direct reference of indexicals offers some privileged insight of direct acquaintance, that when the heiress states, “It is quiet here now”, she knows of something that we don’t, and that when she states, “I am here now”, she speaks of a self certainty that we, as observers, do not attain; a self certainty that transcends linguistic behaviours. However, in so considering, we encounter the aforementioned quandary of accidental reality. An a priori knowledge of “I am here now” that is independent of the context in which the agent operates is not differentiated by the alternative contexts in which it may be thought. It is the same “here now” as thought by the heiress in the trunk of a car, as it is by Joanna O’Toole as she embarks upon her plumbing duties, as it is by Polina Medvedev as she readies herself for a day of dentistry. Yet if it is the same self certainty as dictated by the a prioricity of the character of the statement, irrespective of context, then, upon the apprehension of such self certainty, it becomes a point of arbitrary selection as to which identity the agent assumes.

One may hope to counter this by suggesting that the certainty of self is a property of the agent resulting from the molecular structures of higher order animals from which cognitive awareness emerges. However, if we maintain that this certainty is captured by the character of the indexical statementFootnote 3, then it cannot directly reflect upon the animal agent, just as the analytic certainty of “all spinsters are female” delivers no insight upon whether Joanna O’Toole is a female without the further a posteriori assertion that Joanna O’Toole is a spinster. As an alternative to the material emergence of self awareness, one may care to attach a non-material mind to the agent as a dual substance; as res cogitans to the body’s res extensa. But the same problem rears itself: the self certainty of such a mind, upon attachment to the agent, still demands the a posteriori condition of the existence of the agent’s material body. In summary, if conscious self certainty is a condition attached to an existing agent, then it must be prefaced by an a posteriori judgment, such as “there exists Joanna O’Toole”, thereby ameliorating itself of a priori status. With the additional requirement for the existence of the speaker, we are simply reintroducing Kaplan’s conditional, that if a speaker exists in a certain context, then it is logically valid for that speaker to assert “I am here now”. The logical certainty bakes in an assumption that conditions the assertion with a context wherein there exists an agent who may validly assert their existence in the time and place that they inhabit within that context.

If we remain committed to removing the conditional in order to maintain an anthropomorphic a priori judgment, along the lines of “I know that I am here now and I know this unconditionally”, then we are unable to explain the arbitrariness of the content of the indexical, “I”. We must either accept Kaplan’s impersonal establishment of the logical certainty of a priori indexical statements or confront the inexplicable question as to why I exist, with self certainty, as Joanna O’Toole of Chicago and not as Polina Medvedev of Kaliningrad.

Further problems arise if we attempt to remove the contingent basis for the a prioricity of indexical statements. If we take the certainty of the statement, “I am here now” to be encapsulated within the cognitive faculty of the agent herself, then we find that this self certainty can only be upheld at the expense of all other prospective agents’ a priori knowledge of “I am here now”. Removing the conditional, and thus nesting the a priori within the context of the agent’s own thought, leads to the epistemological state, “As Joanna O’Toole, I have a priori knowledge that I am here now, but I only know a posteriori that Polina Medvedev is in Kaliningrad, now.” But if we also concede that Polina Medvedev obtains a priori knowledge of her own existence in the here and now, then this results in the following contradiction: in one context, there is epistemological certainty of one identity existing as the agent, there and then, whilst in another context, it is only an a posteriori fact that the very same identity exists there and then. Which is true? It cannot be both! If we respond that it depends upon the context, then we are caught in a vicious circle. So long as we attribute the logical certainty of a priori indexical statements to the cognitive state of the agent of the context we remain confounded by the contradiction that in one context, the statement, “I am here now”, is certain as, say, thought by Joanna O’Toole, but in another context, it is only certain as thought by Polina Medvedev. It is only if we detach the logical certainty from the agent’s cognitive state that we avoid the contradiction. The a prioricity of “I am here now” can only apply to an agent’s thoughts and words in the generic sense and not in a sense privileged to the agent.

3 As Exemplified by McTaggart’s Unreality of Time

The case is exemplified by John McTaggart’s paper on the Unreality of Time (McTaggart, 1908), where time is presented as comprising two key ingredients; the subjective experience of time as a single position of the present moment, surrounded by what is known as the past and the future, and the objective designation of time as a series of points on a time scale, each equally valid representations of moments in time. McTaggart notes that both ingredients are indispensable elements of what we know to be the temporal form of experience, and yet there is an inescapable paradox in laying claim to an exclusive “now” as this moment in time whilst acknowledging a series of such moments in time. The point being that if we give credence to the subjective state of temporal existence, then we cannot sustain a multiplicity of such states without encountering the contradiction that a moment in time, M, takes on the status of being past, present and future. McTaggart then considers and rejects the explanation that these seemingly contradictory statuses can be reconciled if taken from their respective contexts.

“It is never true, the answer will run, that M is present, past and future. It is present, will be past, and has been future. Or it is past, and has been future and present, or again is future and will be present and past. The characteristics are only incompatible when they are simultaneous, and there is no contradiction to this in the fact that each term has all of them successively.

But this explanation involves a vicious circle. For it assumes the existence of time in order to account for the way in which moments are past, present and future.” (McTaggart, 1908).

In the same way that the context of a thinking agent offers no escape from the contradiction of pure indexicals when their cognitive significance is attributed to the agent herself, the contradictions of the subjective state of a moment of time cannot be avoided by deferring to another series that acknowledges the alternative temporal states albeit from a temporal standpoint.

“You can never get rid of the contradiction, for, by the act of removing it from what is to be explained, you produce it over again in the explanation. And so the explanation is invalid” (McTaggart, 1908).

Drawing out this conclusion to pure indexicals, if cognitive significance is attributable to the cognitive faculty of the agent, as opposed to simply reflecting the behavioural reality of the context and its content, then the semantics of indexicals must be held up as contradictory as they are applied across different contexts. Any aspirations that you may have of upholding a certainty of self that is particular to your state of affairs, that is, of your context, must come at the expense of alternative self certainties that may be held by other agents in other contexts. It is enough to drive one to solipsism. In order to circumvent such a dramatic response, we must take two steps; first, we must concur with McTaggart that time is unreal, and, more generally, that the subjective awareness that may be attached to pure indexicals is unreal, and second, we must also account for why it is that we have a sense of a subjective reference to space and time, for it is one thing to reject subjectivity by suggesting that all states exist in community with one another within an objective framework that places each agent within a relative spatiotemporal position to each other, but it is another to implant a sense of a subjective perspective within the cognitive faculty whereby we seem to inhabit a given context, seeing things from one perspective, with limited capacity to appreciate things from other perspectives, whilst maintaining a generic sense of self certainty.

To take this second step, we can turn to Immanuel Kant’s critical idealism.

4 The Use of Kant’s Forms of Intuition to Explain the Inexplicable

Kant holds that time and space are the forms of intuition, providing the relative framework for sensibility, whilst sensations are the essential matter of intuition. (A20 | B34)Footnote 4

Time, as the mode by which events are successively presented to the mind, is the form of inner sense. In this, Kant follows Locke’s lead in designating the individual sense of personhood to the temporal flow of inner thoughts, but, for Kant, this sense of self can only be of appearance, as its form does not reflect upon a thing in itself. Under Kant’s transcendental idealism, we must therefore forgo the attribution of direct acquaintance between the cognitive faculty and the agent of a spatiotemporal context. And, here, we can identify the seeds of a solution to the question of how we can have a sense of the subjective without taking the subjective state to be real.

Whilst the inner sense is the means by which consciousness can apprehend each element of reality, the outer sense yields a spatial unity that is necessary for the apprehension of the combined unity of reality. Kant describes the draw and grasp motion of the forms of intuition in his threefold synthesis from the A-Deduction. Firstly, in the synthesis of apprehension in the intuition, Kant prohibits the apprehension of the manifold of intuition without it being drawn through successive impressions.

“Every intuition contains a manifold itself, which however would not be represented as such if the mind did not distinguish the time in the succession of impressions on one another; for as contained in one moment no representation can ever be anything other than absolute unity. Now in order for unity of intuition to come from this manifold (as, say, in the representation of space), it is necessary first to run through and then to take together this manifoldness, which action I call the synthesis of apprehension”. (A99)Footnote 5.

Then in the synthesis of reproduction in the imagination, Kant details how each successive impression must be collected under the reproductive imagination (A102), before, in the synthesis of recognition in the concept, the collective of impressions are brought together under the “unity of synthesis” (A103).Footnote 6

The implications of the respective forms of intuition operating as necessary conditions for the numerical apprehension of reality may be illustrated with the act of counting a pile of pebbles. Let us, for the purpose of this illustration, colour code the pebbles as the green pebble, the brown pebble, the yellow pebble, and so forth. To determine the number of pebbles in the pile, we may embark upon an ordinal counting regime, as in, {1, green pebble}, {2, brown pebble}, {3, yellow pebble}, and so on, until we have run out of pebbles to count. Now, the total number of pebbles in the pile will be maintained regardless of the order in which we count them, but they nonetheless need to be enumerated through successive observations in order to be apprehended as a whole. And here we see the dichotomy of the forms of inner sense and outer sense required for the cognition of a pile of pebbles. On the one hand, there is the subjective form of the inner sense, which may take any number of paths in the linear apprehension of the pebbles, whilst, on the other hand, there is the objective form of the outer sense, whose form remains the same, as the resulting set of pebbles, irrespective of the path taken by the subject when enumerating the pebbles.

The relatively arbitrary order in which one apprehends the pile of pebbles is an inescapable consequence of intuitional experience, but the order itself is only an appearance resulting from the a priori conditioning of experience, and not representative of a real subject of personhood.

Given the immutable status of outer sense, as the completed result of linear apprehension, it is tempting to uphold space as real, in contrast to the ephemeral form of inner sense. This is the position adopted by McTaggart, who identifies the asymmetry of the linear ordering of time as bringing forth the irreconcilable perspectives that leads him to reject the reality of time. McTaggart suggests that a series, such as a sequence of pebbles that can be observed equally forwards as it can backwards, may stand as real without succumbing to the contradictions of a linear series.Footnote 7 In this way, McTaggart hopes to salvage the reality of space. However, such a series, if denuded of direction, lies beyond apprehension. There is no manner in which, for example, I can present the pebbles, even in reference, other than by way of a given order, as example, green, then brown, then yellow. One may, as McTaggart does, propose that the series can be both forwards and backwards; green, then brown, then yellow, and yellow, then brown, then green. However, in so presenting these options, one order must be presented prior to the next, as example, from green to brown to yellow and then from yellow to brown to green, whereby linear order by way of precedence cannot be circumvented. Any attempt to take on an objective perspective that can account for multiple subjective perspectives finds itself introducing its own subjective asymmetries. We, hence, enter into a vicious circle in the apprehension of space not dissimilar to that demonstrated by McTaggart when attempting to evade the contradictions of time.

Through the lens of Kant’s transcendental idealism, space cannot be counted on to persist without linear apprehension, for space is merely an a priori condition of the numerical form through which the objects of experience are to be grasped. The linearity of temporal succession is a necessary complement to the unity offered by spatial simultaneity.

We are thus left with two fundamental forms of intuition, the temporal form of inner sense, through which the manifold is successively drawn, and the spatial form of outer sense, by which the unity of the manifold is grasped in simultaneity. With the form of inner sense, we must opt for one of many pairwise combinations from which a linear order is constructed, whilst the form of outer sense stands as a determined set that is independent of any such ordering. The linear ordering of inner sense is also suggestive of a succession of individual observations, with each moment dedicated to one of many elements of experience, whilst outer sense treats all elements of experience as equally relevant with respect to the whole. And so it may be argued that simply through the necessary conditions of intuitional apprehension do we find the propagation of the subjective inner state as one state amongst the many possible states available across the objective realm of outer sense. This would allow us to explain the arbitrariness of the here now as being no more than an entailment of the intuitional conditions of cognitive experience that ought not be taken as representative of things as they exist in themselves. By avoiding the ontological commitment to the agent of a context existing as a thing in itself, with direct acquaintance to the world surrounding it, we may evade the contradiction that follows whilst maintaining a sense of the subjective here and now as an appearance resulting from the intuitional forms of experience.

Thus far, we have arrived at an explanation as to why it is that we have a sense of self existing in time and space, despite having deemed the existence of the subjective self within time and space as unreal. The subjective inner self and the objective outer world are simply the consequential conditions of the dynamical and mathematical forms that are necessary for cognitive experience. A juxtaposition of the subjective and the objective rooted in the basic forms of intuition, that of succession and simultaneity, as required of enumeration, gives rise to the sense of self as an arbitrary mode of apprehension placed within the frame of objectively existing phenomena.

5 By way of Kant’s Versions of Self

This explanation of the origins of our sense of time and place opens up the deeper question as to why is it that cognitive experience is necessarily encumbered with the dynamical and mathematical conditions of enumeration. Without extending into the variety of debates that are currently in play regarding conceptualist versus non conceptualist interpretations of Kant (Allais, 2016), I will assume the position that the Kantian forms of intuition act as essential enablers to judgment. Following Dieter Henrich’s reading of the B Deduction (Henrich, 1968-9), the unity of time and space is the same unity as demanded in judgment. In this interpretation, the threefold synthesis described in the A Deduction amounts to an inseparable process of judgment in which the generation and application of empirical concepts in the formation of empirical objects coincides with the draw and grasp motion of the productive imagination, from which time and space are rendered.

There are no cognitive building blocks upon which objective reality is built. Reflecting Kant’s edict that synthesis precedes analysis, the realisation of the objective unity of phenomena is achieved only upon the synthesis of recognition in the concept (A103-9). The grounds upon which the conceptual form of phenomenal reality is laid, that is, the noumenal things in themselves, are thus beyond intelligible comprehension. Things in themselves, bereft of the form that is conditional to judgment, are to be considered as a pre-mathematical, noumenal heap.

To establish the direct reference to the indexical, “I”, within Kant’s framework of synthetic judgment, we may turn to two prospective candidates: the transcendental self of the adjudicating I think that accompanies each determination of facts, and the empirical self that avails itself in experience, a posteriori. The empirical self, as the embodiment of inner sense, is no more than an appearance, an artefact of the intuitional conditions of synthesis. And, as an a posteriori determination, it is unable to uphold the a priori character of pure indexical statements, such as: “I am here now”. In this regard, the empirical self fails Kaplan’s character test, so to speak.

And so we must turn to the a priori character of the adjudicating transcendental self, a recourse adopted by Robert Howell (Howell, 2001) and Andrew Brook (Brook, Kant, self-awareness and self-reference, 2001), both of whom look to the irreducibility of the “I” to descriptive terms and the reference to the “I” without the possibility of misidentification, in order to support the candidacy of Kant’s transcendental self to provide the direct reference proposed of the pure indexical, “I”. It is by way of transcendental apperception that the identity of the self is upheld independently of the empirical context of each observation. It is the same “I” that observes the green pebble followed by the brown pebble, then the yellow pebble. However, this “I” cannot represent the actual self as it exists in itself, for Kant upholds the unknowability thesis that no knowledge can be attained of things in themselves, including the self. This only stands to reason. The cognitive self that is responsible for the determination of objective reality must operate prior to the resulting combination upon which any form of identity rests. And by “prior”, I mean antecedent not in the temporal sense but very much in the atemporal sense that is the hallmark of Kant’s spontaneous synthesis. Against this, we see James Van Cleve (Cleve, 1999, pp. 182–186) equating the transcendental self of the I think with the activity of spontaneous synthesis on the basis that it can then offer the self certainty carried by Descartes’ cogito. Yet it is in reaction to the Cartesian ontological self that Kant puts forward an epistemological rendering of self awareness, one that specifically avoids claims of self reference to a thing in itself.Footnote 8 As Brook notes: “Transcendental designation, it is worth pointing out, is purely an epistemological phenomenon. Note, too, that even if this form of designation is transcendental, i.e., to do with the necessary conditions of experience, it is not transcendent, i.e., beyond experience.” (Brook, Kant, self-awareness and self-reference, 2001).

At best, the transcendental self of the I think refers to the analytic unity that is inferred from the synthetic unity established by judgment. To quote Henry Allison, “the analytic unity of apperception presupposes a synthetic unity: (1) that the consciousness of the identity of the I think ‘contains’ a synthesis; and (2) that it is possible only through a consciousness of this synthesis” (Allison, 2004, p. 168). Allison argues that it is only from the “analyticity of the principle of apperception” that the common unity of the identity of the I think as it, for example, considers the green pebble, then the brown pebble and the yellow pebble en route to grasping the entire pile of pebbles, is realised (Allison, 2004, p. 165). It is this common identity carried by the I think that ought to be referred to as the transcendental self, to be distinguished from the judge as it exists in itself, which may be referred to as the noumenal self.

Now, the I think of the transcendental self that is attached to each propositional component of experience demands the asymmetric form of judgment,Footnote 9 that there is green and not brown, that there is brown and not yellow, and so on, against a backdrop of spatial community in which green and brown present equally, suggestive of an objective view of the world free from contextual bias.Footnote 10 As it is attached to each thought in the sequence of judgments, the transcendental self is, itself, consumed into the role of the empirical self.Footnote 11 However, the transcendental self can be said to differ from the empirical self in one important respect; it remains transcendent to the content, or matter, of intuition. Although the empirical self contains no manifold of intuition, as it is simply the boundary condition by which the manifold is traversed (for the shape of the manifold is captured by the grasping function of outer sense, not the drawing motion of inner sense), it is nonetheless identified by the a posteriori content of intuition, as dictated by the context of the empirical self, as an agent of the world. As Joanna O’Toole, for example, registers the location of the spindle, then the O-ring, then the washer of a leaking tap, it is Joanna O’Toole who is identified by the temporal order of these observations, not another identity, who may have registered the parts of the tap in a different order. The identity of the empirical self is thus given a posteriori, with the content of intuition, whilst the transcendental self is established a priori, simply on the basis that there must be an order of succession for there to be cognitive experience.

Under this definition, the transcendental self satisfies the criterion of irreducibility to descriptive terms because it is intuitional in form, if not in content.Footnote 12 There is no conceptual component by way of abstraction from a number of I think observations that might offer a reduction to alternative conceptual constructs.Footnote 13 The transcendental self also meets the criterion of unmistakability, for, as defined here, it is an a priori identity, bereft of the material constituents that bring forth the empirical content. It is the I think that carries no more than the formal character of successive apprehension. Hence it is unable to misidentify itself by virtue of contextual deceptions, such as the fabled scenario of the shopper who, with their shopping trolley, continuously traverses the shopping aisles in order to locate the culprit spilling ever increasing amounts of sugar on the floor, only to come to the realisation that “I am making a mess” (Perry, March, 1979). In this respect, the transcendental self aligns with the character of the indexical, “I”, as exhorted by Kaplan, whereby it offers us a direct reference but only in its a priori designation that, for all contexts, the agent that thinks, or speaks, may validly directly refer to herself as “I”.

One questionable aspect of resolving the transcendental self to a mere functional self reference is that it does not prove an obvious differentiation to any objective form of self reference. In holding up the “I” as simply an identity of unmediated self reference, one might conclude that the statement, “I think of myself thinking”, has the same epistemological basis as the statement, “she is thinking of herself thinking.” The “she” who views the brown pebble followed by the green pebble has a linear apprehension of the world, just as the “I” does, as I view the green pebble followed by the brown pebble. On the surface of things, it might seem that the transcendental self of Kant’s critical philosophy offers no further insight than that of an objective self reference available to all prospective identities.Footnote 14 In this, it would fail to deliver an explanation for our having a particular sense of self. However, the definition of the transcendental self, as I propose here, recognises that there is one and only one means by which the objects of experience can be apprehended. Whereas “she” may observe the brown pebble followed by the green pebble, it is I who observe the green pebble followed by the brown pebble, and, further, both of these sequences of observations cannot be incorporated into the contents of “my” thoughts, not without, at any rate, precedence being given to one order over the other, as previously noted.Footnote 15 The transcendental self, as so defined, captures the necessity for a unique linear ordering in the apprehension of objective reality; a necessity that precipitates a sense of arbitrariness in the empirical self.Footnote 16.

In defining the transcendental self in this way, as a resultant identity of the a priori conditions of synthesis that demand a linear succession of observations, it can be argued that Kant goes beyond the Kaplan form of indexical self reference, insofar as the transcendental self upholds an identity of self that is sui generis, or, at least, first amongst equals. It also delivers more than Hume’s deflationary version of the self that shares with Kant’s noumenal self the inability to show itself by way of any epistemological characteristics. But it falls short of achieving the outcome of direct self awareness sought by Howell and Brook, though it must be noted that any successful endeavour to establish a direct acquaintance with the self can only take us back to the inexplicable arbitrariness of the here and now. Indeed, the resolution to the problem of the arbitrary here and now depends upon the proposition that the self, as we know it, is no more than an appearance, incapable of having actual thoughts in and of itself. This formal version of the self, however, delivers more than a purely functional definition of the expression, I think. By means of the a priori construct of the transcendental self, the cognitive faculty is presented with a necessary sense of self, albeit not a self that gives rise to an actual self reflection that would constitute self awareness.

The solution to the inexplicable arbitrariness of the content of the “I” can, thus, be said to be comprised of three componentsFootnote 17:

  1. 1.

    A noumenal self, responsible for the act of synthesis, but whose form is unknowable (if it were to even be considered as having form) because the activity of thinking is antecedent to the resultant forms of phenomenal reality.

  2. 2.

    A transcendental self that is an epistemological condition recognised by the cognitive faculty; a condition that demands, a priori, that there is a here and now in the linear apprehension of a world that otherwise stands in objective simultaneity independently of its order of apprehension.

  3. 3.

    An empirical self that is no more than an impression given, a posteriori, to the cognitive faculty as the process of synthesis draws together the pre-mathematical noumenal contents of experience under the auspices of the intellectual and intuitional forms so required for cognition.

The third of these components may be seen as a corollary to the first two, although it does likely require the contribution of Kant’s declared stance that the conditions of objective experience are only attained upon a process of synthesis that is ultimately ground upon an unknown material external to the mind (A381,2). Any transcendental notion of self must involve the apprehension of the empirical self through synthesis.

Under this regime, the arbitrariness of the form of inner sense is not something visited upon cognitive experience, but is merely something in the way in which experience appears to be. There are not multiple instances of the “I” communicating with one another, and there are not multiple instances of the “I” sequentially undergoing a series of activities and observations. But there is an a priori necessity for the cognition of space and time, even if such cognition is not of an actual space and an actual time.

And so it is in respect to this third component that we enter into one of the most controversial consequences of Kant’s critical theory; the ideality of time and space.

6 Outstanding Questions on the Ideality of Time and Space

The argument against the ideality of time is that if there is an actual cognitive faculty functioning under the guidance of the conscious self, that is, the noumenal self, then surely it is subject to the same changing conditions that occupy its thoughts. This is the accusation against Kant’s critical philosophy that was first levelled by his peers, Johann Lambert and Moses Mendelssohn, in response to the publication of Kant’s Inaugural Dissertation in 1770. As the argument runs, for the self to experience change, the self must undergo change.

Kant replies, in a letter to Marcus Herz, dated February 21, 1772:

“I do not deny that changes are real, any more than I deny that bodies are real, even though by real I only mean that something real corresponds to the appearance. I can’t even say that the inner appearance changes, for how would I observe this change if it doesn’t appear to my inner sense? If one should say that it follows from this that everything in the world is objectively and in itself unchangeable, then I would reply: Things are neither changeable nor unchangeable.” (Kant I., 1967).

Here, Kant maintains that time is no more than an appearance, but also marks out the means by which the cognitive faculty of the noumenal self is neither changing with time, nor standing still within a moment of simultaneity. This netherworld that Kant carves out for the noumenal self provides it protection from the prospective arbitrariness of the present moment. Kant’s subject is not grasping at multiple states within a single moment, but nor is it changing in time in correspondence with the appearance of change.

By the time Kant reaches his most critical period, with the first publication of The Critique of Pure Reason in 1781, he further tightens his anti-realist position. In response to the argument that: “Alterations are real (this is proved by the change of our own representations, even if one would deny all outer appearances together with their alterations). Now alterations are possible only in time, therefore time is something real.” (A36,7 | B53) Kant states:

“There is no difficulty in answering. I admit the entire argument. Time is certainly something real, namely the real form of our inner intuition. It therefore has subjective reality in regards to inner experience; that is, I really have the representations of time and of my determinations in it. It is therefore to be regarded really not as object but as the way of representing myself as object. But if I or another being could intuit myself without this condition of sensibility, then these very determinations, which we now represent to ourselves as alterations, would yield us a cognition in which the representation of time and thus also of alteration would not occur at all. Its empirical reality therefore remains as a condition of all our experiences. Only absolute reality cannot be granted to it according to what has been adduced above. It is nothing except the form of our inner intuition.” (A37 | B53,4).

Now fully committed to the phenomenal world being a reality that is totally informed by the transcendental conditions of judgment, Kant builds a strong delineation between the empirical reality of phenomena and the absolute reality of things in themselves – an absolute reality that we may term as actuality, in order to distinguish it from the subjective reality of phenomena. The self, as the empirical self, finds itself located firmly within a phenomenal world that is conditioned by the intuitional forms of time and space.

There remains a lingering doubt, notably expressed by Lorne Falkenstein (Falkenstein, 1995, pp. 345-8), as to whether Kant has fully managed to evade the charges that time and space must be maintained as an actual form of experience by virtue of their being properties of our intuition.

To provide a frame with which to review the argument, let us consider synthesis as a cognitive function that takes the unknown external world of noumena as input, and brings forth, through synthesis, the phenomenal world.

Noumena = > Cognitive Function = > Phenomena.

The noumena, being of pre-mathematical form, ought not to be depicted as either a singular input or multiple inputs. Nor can the cognitive function be of an identifiable enumerable form, as it is a function of the unknowable noumenal self, not the known empirical self. The cognitive function thus operates noumenally, that is, in a pre-mathematical and pre-dynamical fashion that is beyond the understanding, and is perhaps somewhat indistinguishable from the noumena that it takes as input. By contrast, the phenomena that are determined by the cognitive function appear successively and simultaneously, in keeping with their intuitional form.

NoumenaN = > Cognitive FunctionN = > Phenomenon1.

= > Phenomenon2.

= > Phenomenon3.

where subscript N denotes Noumenal, that is unenumerable, as a singleton or collective.

The cognitive function is applied spontaneously, generating the forms of space and time by way of the productive imagination, to be distinguished from the reproductive imagination, whose function is to be attributed to the behavioural agent operating within the spatiotemporal forms of phenomenal reality. As Kant notes, “insofar as the imagination is spontaneity, I also occasionally call it the productive imagination, and thereby distinguish it from the reproductive imagination, whose synthesis is subject solely to empirical laws, namely those of association, and that therefore contributes nothing to the explanation of the possibility of cognition a priori, and on that account belongs not in transcendental philosophy but in psychology.” (B152) It is thus that we locate the empirical self aligned to the reproductive imagination as the unique linear enumeration by which phenomena are apprehended, that is, as the temporal form of inner sense.

The sequence of inputs into the empirical self are the sense impressions that we take to be originating from the phenomenal events of reality. This reality, taken at face value, provides a Lockean view of objects of the world impressing themselves upon the mind, via sense impressions, giving the mind a direct acquaintance with the world that surrounds it. Kant’s transcendental idealism dismantles this view by placing epistemology in front of ontology, whereby phenomenal interactions are subsequent to, not the cause of, cognitive determinations. It is in this fashion that we see the clear philosophical differentiation that Kant places on the noumenal self, as the producer of space and time, from the empirical self that is rendered as part of space and time. In this constructivist epistemology, sense impressions ought not to be seen as the input into the actual self, that is, the noumenal self, but as part of a worldly apparatus that sustains empirical reality, leaving the world as it exists in actuality divorced from space and time.Footnote 18

The question remains: can there be any suggestion of spatial and temporal form without there being something actually spatial and temporal to these representations? This is a question equally applicable to space as it is time, as it is simply a question of properties being real, whether they are attributable to mental representations or external objects (Falkenstein, 1995, p. 344).

Of further concern is the problem of localisation, as highlighted by both Falkenstein and Brook. If space and time are not given to the cognitive function, but are determined by the cognitive function, one is wont to ask, why do we have the impressions of a localised spatiotemporal reality that we do? Why should I see an oval pebble here, a squarish pebble there, and, above them, a circular pebble? Why do I apparently see different shapes at different times and places? As Falkenstein puts it:

“If spatial and temporal order are supposed to be constructed by some combinative procedure of productive imagination out of matters that, as originally given, are entirely non-spatiotemporal, then Kant has a localization problem of monumental proportions. Why, ultimately, are sensations placed here rather than there, now rather than then?“ (Falkenstein, 1995, p. 250).

Brook sees the situation in equally dire terms:

“For Kant, localization is a really severe problem. Once space and time are separated from incoming intuitions, once they are viewed merely as properties that intuitions are represented to have, neither perceptual pathways or filters nor acts of synthesis nor anything else could use spatial information to distribute elements of experience in space, temporal information to distribute elements of experience in time.” (Brook, Kant and Time-Order Idealism, 2013).

Now, Brook is surprised at how little attention the problem of localisation has received. He surmises that most commentators have avoided the problem by removing time-order from Kant’s constructivist epistemology because of the presumed unsustainability of maintaining it.Footnote 19 The problem with applying a constructivist epistemology to space and time is that the vagaries of spatiotemporal reality seem to have no credible basis if simply left to our own cognitive inclinations.

Both Brook and Falkenstein are of the mind to push the question back on to the incoming noumena, demanding that we find the seeds of space and time in the delivery into the cognitive function.Footnote 20 However, in placing the onus upon the incoming noumena, we have not necessarily overcome the crux of the problem. The problem of localisation, as a question of the arbitrariness of the presently recognised state of affairs, assumes that there is indeed a thing that we ought to call the present cognitive state of affairs, a thing distinct from other prospective cognitive states of affairs, for the problem of localisation is dumbfounding precisely because of the inexplicable production of such a state by the cognitive function, with no external drivers to determine one state of affairs over another. However, should we take the cue of realism from Falkenstein and Brook, and sew the seed of the present experiential arrangement of spatiotemporal features within the inputs to the cognitive function, then all we have achieved is to push the problem back towards the actuality of external reality. And thus we confront the fact that there is an inexplicable arbitrariness to the current experiential moment, whether it is grounded on external realities, or whether it is a determined by the mind.

One may care to explain the current state of affairs through the dictates of phenomenal reality. The present experiential moment is the result of a series of events, each conforming to a set of laws prescribed by nature. However, this does not account for the present observations by the cognitive faculty. The causal forces of nature can explain why “I am at this location at this point in time” so long as we take the indexical, “I”, of this statement as only providing direct reference in the behavioural sense. If we take the direct reference of the indexical, “I”. as pertaining to the cognitive state of the agent rather than the behavioural state of the agent, then it becomes an arbitrary condition as to whether you, insofar as you may reference yourself as “I”, are inhabiting the context that you currently find yourself in, at this moment, reading this paper, or whether you are the agent of another spatiotemporal context.Footnote 21.

As Brook is wont to question why there is a distinct lack of commentary on the problem of localisation resulting from Kant’s ideality of time, the same may be put to the broader question of the arbitrariness of the present moment, a problem that cannot be ignored through the dismissal of the ideality of time, for it is a problem applicable to both transcendental realism and transcendental idealism.

7 The Noumenal Netherworld of Actual Experience

If we take the view that the self is real insofar as (1) it exists within a spatiotemporal framework as a cognitive subject with a cognitive view of the world, from the inside out, so to speak, and (2) its essence is captured by the character of the indexical expression I think, as in, “I think that the leak coming from that faucet is due to wear in the washer”, then we are confounded by the question: why, when we take a peak, from the inside out, from the generic I think out to the reality of the spatiotemporal world, do we see this particular view and not another. To avoid such a quandary, the cognitive faculty must be removed from any context that envelopes it within a linear framework. And to avoid the problem of localisation that occurs when the spatiotemporal context is conferred upon the phenomenal reality, as determined by the cognitive faculty, space and time must be removed from the appearance of phenomenal reality as well.

The forms of intuition thus can only stand as a presupposition to our experience, not as attributes that are actually applied to the elements of the world as it exists in itself, or as it appears to exist in itself.

To help illustrate the role of a priori supposition, as such, consider its use within the judicial presumption of innocence. As we presume innocence in the accused, we do not guarantee that they are innocent, just that, without evidence to the contrary, the default position is that they are innocent. If we were to assume their innocence, on the other hand, then the assertion of innocence is incorporated into our appraisal of events, and so presents as an accompanying proposition to be deployed with all other evidence. A presupposition, however, plays no such active role in the assessment of evidence.

Succession and simultaneity are, likewise, to be no more than presumed of the phenomenal world that we inhabit.

To understand why time and space are to be relegated to no more than presuppositions of experience, we can look into how these forms of intuition are intended to work together for the apprehension of worldly phenomena. The draw function of inner sense enables the successive apprehension of elements of reality whilst separating out points of distinction between them to avoid contradiction. The grasp function of outer sense brings together the elements of reality in order that the entire picture is able to be apprehended in simultaneity. However, it is evident that these two functions are operating in opposition to one another. The imagination is either drawing one point at a time, fixated upon the essence, as per Leibniz’ simple representations, else it is grasping the totality. To Kant, the former renders incomprehensible formlessness, as cognition requires the relative form of intuition, whilst the latter renders the contradictions of distinct marks being apprehended in simultaneity. Succession and simultaneity may be, by this argumentFootnote 22, presumed of experience but never attained in actual experience.

The dynamics of the flow of time as a pure succession of moments defies realisation, for each moment, as such, cannot be realised without the context of other moments. But nor can the constituents of space be grasped in static simultaneity, as each point lapses, directionally, into another point. Kant’s unity of consciousness is unable to lay claim to a fixed set of representations. Cognitive experience purports to be both dynamic (of changing perceptions) and mathematical (of many perceptions) but achieves neither. The world as it is in actuality is neither temporal nor spatial. As Kant notes in his letter to Herz, “Things are neither changeable nor unchangeable.” (Kant I., 1967) But there is a further, most important, consequence, to this proposal. And that is that we, as we exist in ourselves, are inhabitants of a netherworld situated between the boundaries of time and space, presupposing of both, but realising neither in actuality.

The two conditions of experience, space and time, form an awkward juxtaposition in our contemplation of reality, both necessary as presuppositions for cognitive judgment, but both unreal due to their mutual incompatibility. On the one hand, the form of outer sense presents the extension of intuition in simultaneity, with no precedence given to one point over another, yet, on the other hand, the form of inner sense dictates that the points of intuition are to be apprehended in succession, with precedence given ultimately to one of the many. This gives rise, one must contend, to the presumption of an, albeit arbitrary, present state, as suggested by the supposition of the subjective perspective against the backdrop of the supposed objective world. Hence, the endowment of the sense of there being an arbitrary here and now is wholly explicable from the demands of cognitive judgment. The question of the inexplicable arbitrariness of the here and now, however, does not afflict us in actuality, because the self, as the noumenal self, navigates between the conditions of subjective succession and objective simultaneity, but it does present as a bedazzling paradox if the idealised boundary conditions of our cognitive experience are in any way taken as real.

Constructivist epistemology is significantly tempered by the notion that phenomena may be built upon the presuppositions of intuitional form that are never actualised. It is, in fact, the reverse approach to that taken by Falkenstein and Brook, who seek to resolve the problem of localisation by pulling the intuitional form of the phenomenal output of judgment back to the noumenal input; a move that only leads us to the more intractable problem of the arbitrariness of the current state of external reality. In contrast, my proposal is that the formlessness of the noumena be pushed forward into the output of the cognitive function, with space and time presenting as no more than unattained boundary conditions. The role of the cognitive function is simply to presume intelligible forms regarding the conditions of reality, without applying those conditions in any constructive sense.

NoumenaN = > Cognitive FunctionN = > PhenomenaN (with only the supposition of intuitional form).

This picture is not such a great departure from Kant’s critical philosophy as one might think. In the 1772 letter to Marcus Herz, Kant ascribes the notion of the all powerful intellect that can determine reality to the intellectus archetypi, against which he compares the notion of a purely receptive intellect, the intellectus ectypi, noting that: “the possibility of both an intellectus archetypi (on whose intuition the things themselves would be grounded) and an intellectus ectypi (which would derive the data for its logical procedure from the sensuous intuition of things), is at least intelligible. However, our understanding, through its representations, is not the cause of the object (save in the case of moral ends), nor is the object the cause of the intellectual representations in the mind (in sensu reali).” (Kant I., 1967)Footnote 23

Neither the great adjudicator, the intellectus archetypi, nor the great recipient, the intellectus ectypi, depict the operating mode of our conscious experience. Kant’s a priori forms of intuition are to be read as conditions that are to be supposed of, but not applied to, the actual world.

8 Conclusion

In this paper, I have suggested that Kant’s forms of inner sense and outer sense, time and space, can act as conditions that are but presumed of cognitive experience, not able to take hold as definite attributes. I have also proposed how these forms of intuition can engender Kant’s transcendental self, the ubiquitous I think, that is to accompany all propositional determinations, presenting the asymmetry of subjective inner determination against the symmetry of objective outer reality, which drives a sense of the empirical self as the purely temporal component by which phenomenal reality is apprehended.

This approach allows us to navigate the inexplicable question of why it is that “I exist at this point in time at this allotted place” when the indexical, “I”, cannot be in reference to a self awareness that is carried by the empirical self because the indexical, “I”, presents a self certainty that must stand independently of empirical conditions. We can simply adopt the decidedly Kantian approach of rendering the question obsolete because it does not pertain to things as they exist in themselves. The a priori status of pure indexical statements, such as “I exist here now”, are, to use a Kantian refrain, quid juris, but not quid facti. They are conditional to experience, though experience, in itself, is not something that occurs within a spatiotemporal framework, only something that the cognitive faculty presupposes to occur within a spatiotemporal framework.

This does open up a question of epistemological scepticism that shadows Kant’s unknowability thesis: if the conditions that produce our sense of self, our empirical self, are born of none other than a presupposition of the cognitive faculty, then is it justifiable to assert that “I” am Joanna O’Toole of Chicago, in 2022, when “I” may equally be said to exist as Polina Medvedev of Kaliningrad, in 2032? This form of scepticism, however, is built upon the assumption that things in themselves exist independently of the state of existing as one identity or another, that is, with all asymmetry of linearity removed. However, such independence from linearity would take us directly to the symmetry of spatial simultaneity, whereas things in themselves, as in accordance with Kant’s transcendental idealism, are neither successive in form nor simultaneous in form. Noumenal reality neither commits to a linear order, nor equivocates between alternatives. It is this state of formlessness that allows for the content of intuition to provide meaning for propositional assertions concerning phenomenal reality, such as, for example, “I am Joanna O’Toole of Chicago, in 2022”.Footnote 24

Though able to provide meaningful content to the intuitional form of phenomena, the actual world in which we live is beyond the faculty of the imagination. Even our thoughts, as they exist in themselves, must be said to be devoid of temporal and spatial qualities. Thoughts cannot be meted out in succession, nor strung together in simultaneity. This may be one of the most confounding aspects of Kant’s idealism and yet, although difficult to accept, accept it we must if we are to resolve the otherwise inexplicable question of the arbitrariness of the here and now.