p23

14 Strictly speaking, because of the continuous structure of time, there is no time “directly after” any other time. However, for the purposes of our overall argument, we really only need to consider a variant of Two Rooms where your duplicate will be destroyed L/2 units of time after noon (where L is the value in Minimal Positive Duration). Then, answering “yes” to this variant of Two Rooms would support a modified version of Not Wholly Future Dependent, which would read “For any time t, if you are conscious at time t, then there must be some phenomenal property P that you instantiate over some temporal interval T, where no time strictly later that t + L/2 is a member of T, such that you are conscious at time t in virtue of instantiating P”. This modified version of Not Wholly Future Dependent could then be used to derive a modified version of The Inductive Premise below, which would read “If you are conscious at t, then you are conscious during the interval [t-L/2,t]”. This modified version of The Inductive Premise leads to the very same absurd conclusion. For the sake of simplicity, however, we will stick to the simplified version of Two Rooms in the main text.8 To bring out the counterintuitiveness of this case, suppose that whether or not your duplicate will continue to exist after noon crucially turns on some indeterministic quantum event. For example, suppose that, at noon, there is an objective chance of 1/2 that a bomb will go off after noon. If your duplicate is conscious at noon if and only if the bomb fails to go off after noon, then at noon, there is an objective chance of 1/2 that your duplicate is currently conscious! But we do not think that it can be an objectively chancy matter whether someone is presently conscious. If you agree with us about how to answer Two Rooms, then we think you should endorse Not Wholly Future Dependent. For suppose, as a reductio, that Not Wholly Future Dependent was false. So, as an example, suppose in Two Rooms that you are conscious at noon only in virtue of phenomenal properties that partly extend to times strictly after noon. By hypothesis, your perfect duplicate does not instantiate any of these phenomenal properties, since they do not even exist after noon. So, if none of the grounds for your being conscious at noon are had by your perfect duplicate, then it seems like your duplicate would not be conscious at noon. After all, they would not instantiate any phenomenal property that would make them phenomenally conscious at noon. In response, one could try to resist this argument by claiming that your duplicate is conscious at noon in virtue of having different temporally extended phenomenal properties than the ones responsible for your own consciousness at noon. In particular, one could think that your duplicate is conscious at noon in virtue of instantiating a phenomenal property that does not extend past noon (e.g. that is instantiated for some interval [t1,t2], where t2 is the time at noon), even though you (by assumption) do not instantiate any such property. Our first response to this objection is that it violates the very intuition that it is meant to be defending. The reason why it is plausible to think that your duplicate is conscious at noon is because it seems that whether or not someone is conscious at some time can’t crucially depend on what may or may not happen after that time. However, what could explain why you and your duplicate do not instantiate the same phenomenal properties until noon? Given that the only difference between you and your duplicate concerns what happens strictly after noon, the only possible explanation for why there would be this phenomenal difference before noon must be because of the physical difference between you and your duplicate after noon. So, while this view might avoid having to say that whether or not someone is conscious at a time depends on what happens after that time, this view does have to say that which (basic) phenomenal properties someone instantiates over some interval depends on what happens to them strictly after that interval. In other words, this view doesn’t end up avoiding the future dependence of conscious experience after all. Our second response to this objection is that it violates Phenomenal Internalism. Given Phenomenal Internalism, if your duplicate is conscious at noon in virtue of instantiating a phenomenal property that does not extend past noon, then you must also instantiate this property, on the grounds that you both are physical duplicates up to noon. However, this contradicts our9 assumption that you do not instantiate any such property. Although it is of course debatable whether phenomenal properties are really intrinsic, we think it is at least a heavy cost of this objection that it must reject Phenomenal Internalism.15 In sum, we think that anyone who maintains that you and your duplicate would both be conscious at noon in Two Rooms should endorse Not Wholly Future Dependent. 4. Have You Existed Forever? Unfortunately, Minimal Positive Duration and Not Wholly Future Dependent imply something absurd, namely that you have an infinite past. Let “L” name a lower bound for the shortest duration that a phenomenal property might have (as discussed in Minimal Positive Duration). The crucial step is the following: The Inductive Premise: If you are conscious at t, then you are conscious during the interval [t-L,t]. The Inductive Premise is a straightforward consequence of Minimal Positive Duration and Not Wholly Future Dependent. Suppose you are conscious at t. Then, by Not Wholly Future Dependent, you must instantiate some phenomenal property P that does not extend past t, in virtue of which you are conscious at t. By Minimal Positive Duration, that phenomenal property must be instantiated over a temporal interval of at least length L. Therefore, you must instantiate a phenomenal property, at least, over the interval [t-L,t], establishing The Inductive Premise. It should be noted that the full strength of Minimal Positive Duration and Not Wholly Future Dependent are needed to derive The Inductive Premise. For example, if we weaken Minimal Positive Duration to Positive Duration and maintain Not Wholly Future Dependent, then if you are conscious at t, it is consistent that you are only conscious throughout some arbitrarily short interval (t,t], where, for any time in that interval, you are conscious in virtue of instantiating a temporally extended experience that only extends into the past and present without including any time at or before t.16 On the other hand, if we retain Minimal Positive Duration and drop Not Wholly Future Dependent, then if you are conscious at time t, it may be that you are conscious at t wholly in virtue of instantiating phenomenal properties that are extended over the present and future, which has no consequences about your past experiences.17 15 One prominent way to motivate the claim that phenomenal properties are not intrinsic properties goes by way of “Externalist Intentionalism”, according to which phenomenal properties constitutively depend on representational properties, and representational properties constitutively depend on features of the external environment (e.g. see Dretske (1995), Armstrong (1999), and Hill (2009)). For an empirical defense of an internal, brain based account of consciousness, see Pautz (2021). 16 A half open interval (x,y] includes all times t such that t > x and t ≤ y. 17 It is also worth noting that dropping Not Wholly Future Dependent and maintaining Minimal Positive Duration does not entail the ‘reverse’ conclusion that you will exist forever into the future. On its own, Minimal Positive Duration is perfectly compatible with conscious beings living normal, finitely long lives. For example, there could10 With The Inductive Premise in hand, we now only need to repeatedly apply it. If you are conscious at t, then you are conscious at t- L, so then you are conscious at t- 2L, so then you are conscious at t- 3L, etc. By applying The Inductive Premise repeatedly, we can prove that if you are conscious at t, then you are conscious at t- NL, for any positive integer N. Since we can make N arbitrarily large, it follows that if you are conscious at time t, then you have been conscious for an infinite amount of time prior to t. In effect, the argument shows that your consciousness can’t have a beginning. For the sake of a reductio, suppose that your first moment of consciousness was at time F (presumably, time F may have occurred when you were at a certain late stage of being a fetus). You couldn’t have been conscious at that time in virtue of having an instantaneous, durationless experience, or in virtue of having an experience of length shorter than L. Furthermore, we don’t want to say that your being conscious at that time is wholly future dependent (for that would entail that you wouldn’t have been conscious had you been destroyed directly after F). So, you must have been conscious at time F−L all along, contrary to our assumption.18 5. Is The Argument Soritical? One may be tempted to think that this argument is merely a version of the notorious sorites paradox. We have The Inductive Premise, which is used repeatedly to carry us from an obvious truth (you are conscious at some time or other) to an obvious falsehood (you have been conscious for an infinite amount of time). This looks suspiciously similar to the structure of an argument that would have us conclude that a single grain of sand counts as a “heap” on the basis of an analogous inductive premise. If one suspected that the concepts used to formulate and argue for The Inductive Premise were infected by vagueness, then one might naturally conclude that the argument in the previous section must fail in the same way that other soritical arguments fail (whatever that way might be). be a conscious being that only exists throughout the interval [t- L/2, t + L/2], where for any time during that interval, the conscious being is conscious in virtue of instantiating a phenomenal property over the temporal interval [t – L/2, t + L/2]. 18 The intuitive idea behind this kind of argument- that there is a tension between the claim that our experiences are temporally extended and the claim that our experiences do not depend on the future- has been stated before. For example, Dainton (2018) mentions this tension in his survey of the literature on the experience of time. However, to our knowledge, this tension has not been formulated precisely. Moreover, once one formulates this tension precisely, a number of subtleties emerge. First, it is important to distinguish between our experiences being future-dependent and our experiences being wholly future-dependent. The mere claim that our experiences are future-dependent does not generate the kind of worries behind Two Rooms. Second, there is no inconsistency in holding that our experiences are both temporally extended and not wholly future dependent. There is only the threat of the (logically consistent) absurd conclusion that we have an infinite past. Third, in order to derive this absurdity, more is needed than the mere claim of Positive Duration. One also needs a principle like Minimal Positive Duration. Finally, as we will discuss in the next section, a full discussion of this kind of tension should also be supplemented with a discussion about the potential soritical nature of the argument. For all these reasons, we believe that this kind of tension deserves a more precise formulation than it has previously been given.11 We have two responses to this prima facie worry, one more general and one more specific. The first general response is that there are good theoretical reasons for believing that claims about the metaphysical structure of conscious experience, unlike claims about heaps, are not vague. Many philosophers have argued that conscious experience is fundamental and irreducible. Dualists, Panpsychists, and Idealists all agree on this point.19 However, if any of these views are true, then attributing vagueness to the metaphysical structure of conscious experience is tantamount to attributing fundamental, metaphysical indeterminacy into the world. This kind of fundamental worldly indeterminacy, as opposed to the usual linguistic indeterminacy associated with words like “heap”, is highly controversial.20 More importantly, many philosophers, physicalists and non-physicalists alike, have felt that conscious experience isn’t the kind of thing that could be vague. If consciousness were vague, there could be borderline cases of consciousness; but as many philosophers have acknowledged, it is difficult to make sense of a borderline state of consciousness. Jonathan Simon (2017) gives a helpful analogy: Intuitively, asking whether someone is phenomenally conscious is like asking whether the light is on. The light may be brighter or dimmer, but if there is any luminescence at all, then it is on. Experience may be more or less intense, more or less attentive, closer to waking or closer to dreaming, but if at some specific moment it is not completely, totally, absolutely dark inside, then at that moment there is some phenomenal consciousness. (2105-2106).21 Our second main response is that, even if our two claims regarding consciousness are ultimately vague, the main problematic sources of vagueness can be alleviated. Perhaps the most worrying case of vagueness is the vagueness associated with picking a value for “L” in Minimal Positive Duration. If the exact endpoints of temporally extended phenomenal properties are indeterminate (so that phenomenal properties are “fuzzy” at their borders), some choices of L might not make Minimal Positive Duration into a determinate truth. However, it seems to us that anyone who is sympathetic with Minimal Positive Duration will grant that there is some L such that it’s perfectly determinate that all temporally extended phenomenal properties have length at least L (e.g. L might be half of the Planck time). With respect to Not Wholly Future Dependent, it seems to us that it’s problematic to think that in Two Rooms your perfect duplicate’s conscious state at noon even indeterminately depends on what may go on in the future. It should be a perfectly 19 For classic defenses of dualism, see Jackson (1982) and Chalmers (1996). For defenses of panpsychism, see Strawson (2003), Chalmers (2013), and Goff (2017). For defenses of idealism, see Kastrup (2018) and Chalmers (2019). 20 See Barnes (2010) for an overview of the arguments against metaphysical indeterminacy. 21 See also Searle (1992: 3), Strawson (1994: 153), Chalmers (1996: 106), and McGinn (1996: 14). Antony (2006, 2008) and Tye (2021) also defend the claim that consciousness is sharp rather than vague, while Hall (Forthcoming) defends the view that there could be borderline states of phenomenal consciousness. See Lee (2020) for a disambiguation of different questions that often get associated with vagueness and consciousness.12 determinate matter that your duplicate’s conscious state at noon is fully determined by the state of the world up to and including noon. Let us consider the argument again. Suppose it’s a perfectly determinate fact that you are conscious at time t (presumably now is such a time). Then, you must instantiate some temporally extended phenomenal property such that it’s perfectly determinate that that phenomenal property is at least length L (by our choice of L above), and it must be perfectly determinate that that phenomenal property does not extend into the future (otherwise, it would be indeterminate whether we have violations of Not Wholly Future Dependent). Consequently, it will be a perfectly determinate matter that you must be conscious at time t−L, which supports the (perfectly determinate) truth of The Inductive Premise. 6. Time-Slice Internalism Presumably those who accept Minimal Positive Duration will want to deny that we have all lived forever. Some of us have lived 80 years, and some have lived even 100 years or more; but certainly none of us have lived before the Big Bang! Unfortunately, the only way to avoid this absurdity is to deny Not Wholly Future Dependent. In light of the fact that Minimal Positive Duration leads to rejecting Not Wholly Future Dependent, is the appropriate response to reject Minimal Positive Duration, or is it to simply bite the bullet and deny Not Wholly Future Dependent? The right answer to this question will depend on how (im)plausible the alternatives are to Minimal Positive Duration. Insofar as there are plausible alternative accounts of the temporal structure of experience, there is more reason to reject Minimal Positive Duration in favor of one of these alternative accounts, and insofar as there are no plausible alternatives, there is more reason to bite the bullet and reject Not Wholly Future Dependent. In order to bolster our argument against Minimal Positive Duration, we will therefore turn to arguing for the plausibility of an alternative account of the temporal structure of experience, which is centrally committed to the following thesis: Time-Slice Internalism: If x is conscious at time t in virtue of instantiating a phenomenal property P, then P must be instantiated at the instant of time t (rather than over a temporally extended interval). Moreover, given the psycho-physical laws (if there13 are any), the phenomenal properties had by x at time t supervene on the intrinsic physical properties of x at time t.22,23 In short, on this view basic phenomenal properties are both instantaneous and intrinsic. We will start by canvassing some preliminary motivations for finding Time-Slice Internalism attractive (section 7), after which we’ll respond to some of the main criticisms that it faces (sections 8-10). 7. Preliminary Motivations The first and most obvious reason to accept Time-Slice Internalism is that it implies Not Wholly Future Dependent. We think this feature of Time-Slice Internalism should be especially powerful to those who believe that phenomenal properties are fundamental, such as Dualists, Panpsychists and Idealists. It is easy to think of examples of non-fundamental properties that are dependent on the future. For example, whether a plane has the property of being five minutes from take-off obviously depends on the future. However, other examples of fundamental properties, such as mass, charge, or spin, are all plausibly not dependent on the future. Whether (say) a fundamental particle has a particular mass or electric charge at a particular time does not depend on what may or may not happen to that particle after the relevant time.24 Although it is consistent to think that fundamental phenomenal properties differ from all other fundamental properties in this respect, we think it is much more natural to treat fundamental properties similarly in this respect. A second reason to accept Time-Slice Internalism is structurally similar to the first. When one considers other plausible examples of fundamental properties, such as mass, charge, or spin, none of these properties are temporally extended properties. Basic units of (say) mass are had at particular times, rather than over (say) hundreds of milliseconds. In fact, it would seem objectionably arbitrary if fundamental properties were instantiated over some temporally extended length (e.g. 173 milliseconds). Why that temporally extended length rather than some 22 Although a view like Time-Slice Internalism has been historically defended by, for example, St. Augustine and Thomas Reid, nowadays it is much less popular. However, for contemporary discussion and defense of this kind of view, see Chuard (2011, 2019, 2020). It should be noted however that Chuard only defends the view that basic experiences are “very short, perhaps even instantaneous” (2020: 621). 23 There is certainly logical space to hold views that are distinct from both Time-Slice Internalism and Minimal Positive Duration. For example, one could adopt “Time-Slice Externalism”, which accepts the first sentence of Time-Slice Internalism and rejects the second sentence. However, because we think there are strong reasons for endorsing Phenomenal Internalism, we won’t further pursue this view here. One could also adopt Positive Duration and reject Minimal Positive Duration, but because we think most of the motivations for Positive Duration support Minimal Positive Duration (as we argued in section 2), we also won’t explore this option further. 24 A possible exception to the general rule that fundamental properties are not future-dependent are certain interpretations of quantum mechanics that involve “backwards causation”, but such interpretations are highly controversial. For an overview of such interpretations, see Friederich and Evans (2019).14 other temporally extended length?25 Again, while it is consistent to think that fundamental phenomenal properties are unlike every other fundamental property in this respect, it seems to us to be more natural to treat fundamental properties similarly in this respect. A third reason is that Time-Slice Internalism is neutral on broader questions about the metaphysics of time.