Motivating Disjunctivism

1 Introduction

In his excellent and thought-provoking book, Perception and Knowledge, Walter Hopp offers his readers a tour de force, tackling a range of central topics in epistemology and the philosophy of perception. Although his views and arguments are often heavily inspired by Husserl, Hopp’s agenda is systematic rather than exegetic. In Chap. 6 of the book, Hopp criticizes some prominent versions of the disjunctive theory of perceptual experience and offers his own “moderate disjunctivism” as an alternative.¹ In this paper, I raise some critical questions vis-à-vis some of Hopp’s objections to supposedly less moderate versions of disjunctivism. In particular, I suggest that Hopp distances himself from certain ideas that are absolutely central to standard motivations for disjunctivism, thereby leaving his own adoption of disjunctivism insufficiently motivated. With one or two exceptions, I shall not discuss how Hopp’s views relate to those of Husserl. Just like Hopp himself, I will focus on the systematic issues at stake.

I start by contrasting disjunctive and conjunctive theories of experience and briefly indicating the main motivation for embracing the former sort of view. I also suggest that disjunctivism is prima facie implausible and hence can only be reasonable to adopt if the conjunctive alternatives are seriously flawed. Then I discuss Hopp’s criticisms of the disjunctive views that he collects under the heading of “the relational view” of experience. I argue that there are several indications that Hopp rejects the most common motivations for disjunctivism. Finally, then, I suggest that it is not clear that Hopp offers any good alternative motivation for his “moderate disjunctivism”; nor does he seem to make any attempt to address the standard objections to disjunctive theories.

Before beginning my critical discussion of these issues, let me emphasize that I hold Perception and Knowledge to be one of the most important contributions to phenomenology to have appeared in recent years. The lucidity of Hopp’s prose, and his ability to make phenomenology speak to issues in analytic epistemology and philosophy of mind, make his book accessible and relevant to philosophers who do not normally pay attention to phenomenology. Hopp has produced a philosophical work of the first rank which deserves to be carefully read and critically engaged with.

2 Conjunctivism Versus Disjunctivism

Conjunctive theories of perception hold that a case of genuine perception²—seeing a black horse, say—breaks down into two components. First, a subject is having a sensory experience as of a black horse. In and of itself this experience is not a case of genuine perceptual contact with a mind-independent object. Second, this experience has a certain aetiology, which, inter alia, will typically involve an actual horse reflecting light onto the subject’s retinas.³ On the conjunctive view, then, the perceptual experience one enjoys when actually perceiving is of the very same type as the experience one may have when hallucinating—the two only differ with respect to aetiology. As Dretske writes:

Although my present black-horse experience is an experience of a black horse (I am, that is, seeing a black horse), I can nonetheless have exactly the same type of experience, a black-horse experience, without its being an experience of a black horse or, indeed, an experience of any object at all (Dretske 1995, p. 24).

It is not only intentionalists (or “representationists”) who agree with this. Qualia theorists and indirect realists, for example, will typically qualify as conjunctive theorists. The crucial point is not whether or not you believe that there are non-representational sensational components in perceptual experiences; what matters is that you believe that the very same type of experience could be had even in a situation where there was no mind-independent object for it to be a perception of. Therefore, you can also be a conjunctive theorist while maintaining that the experience cannot be had in the absence of an internal or mind-dependent object. The important thing is that the same type of experience can be had independently of how matters stand in the external, mind-independent world.

Disjunctivists reject the conjunctive picture. They maintain that a genuinely perceptual experience is an experience of a different fundamental kind from a hallucinatory experience. Unlike the latter, a genuinely perceptual experience, in and of itself, is a case of perceptual contact with our mind-independent environment. The disjunctivist holds that this is so even if the subject is unable, through undergoing the experience or reflecting on it, to distinguish the genuinely perceptual experience from a possible hallucinatory counterpart. The actual horse itself, as it is sometimes put, is a “constituent” of the genuinely perceptual experience (e.g., Campbell 2002, p. 117; Martin 2004, p. 39). It is therefore not possible to have this sort of experience in a case where there is no horse there to be seen.

It is important to note that the disjunctive theory objects to the conjunctive picture as such—not merely to indirect realist versions of it. In other words, the disjunctivist’s complaint is misconstrued if identified with the claim that conjunctive theories posit intermediate entities (a “veil of appearances”) between the experience and the external world. This is fortunate, for on most current versions of conjunctivism, the idea is that perceptual experiences are a species of representational states. And this, it is commonly believed, precisely eliminates the need for sense-data or other intermediate entities (for a clear statement, see Martin 2002, p. 397). So if disjunctivism were exclusively or primarily a reaction to indirect realism, it would be something of an anachronism.

Many philosophers have argued that disjunctivism is deeply problematic. In particular, the disjunctivist is believed to encounter difficulties accounting for the case of a possible “causally matching” hallucination.⁴ For present purposes, we can illustrate the problem as follows. Suppose in one case I am perceiving a white coffee mug. In another case, there is no mug in front of me, but neuroscience has advanced a bit further than its current state, and a scientist is stimulating my optical nerve (say) directly in the same way as it would be if I were perceiving a white mug in front of me. Ex hypothesi the proximal causes (everything “downstream” from, and beginning with, the stimulation of my optical nerve) of this experience would be exactly the same as in the first case; only the so-called “distal causes” would differ. Disjunctivists, however, are committed to the claim that the two experiences are of fundamentally different kinds. Thereby it seems they are just denying the obvious. This problem is widely believed to be close to fatal for the disjunctive theory.

So what might the disjunctive theory have to recommend it? In order to see what, from the disjunctivist’s point of view, is wrong with conjunctivism, reflect on a case where you are (non-veridically) hallucinating a female character who looks just like your mother. Your mother—the woman herself—is not there. And yet you are having an experience as of your mother (or someone looking just like her). Thus, in this case, your experience must “fall short” of your mother in the sense of being compatible with her absence—she is absent, after all, and you are having that experience. Now, since the conjunctive theory accepts that what goes for hallucinatory experiences goes for genuinely perceptual experiences, it must be the case that the latter sort of experience, too, falls short of your mother in the sense of being compatible with her absence. Your mother’s actual presence is relevant to the causal story and thus to the question of whether your experience counts as genuinely perceptual or not; but as far as the experiential episode itself is concerned, the actual presence (or even existence) of your mother is not part of the story at all. But if your mother’s presence or absence makes no difference with respect to the sort of experience you are having, then it seems that whatever your experience makes you aware of—or “acquaints” you with, to use Russell’s term—it cannot be your mother. For the experience does whatever it does—“representing” your mother as standing in front of you, or putting you in touch with a “maternal” sense-datum—regardless of whether or not she is present. This is crucial. The conjunctivist, as McDowell writes, is compelled to posit “a highest common factor of what is available to experience in the deceptive and the non-deceptive cases alike” (McDowell 1998, p. 386). Since the conjunctivist believes that the very same (type-identical) experience can be had in perceptual and hallucinatory cases, whatever the experience as such accomplishes in the one case, it must accomplish in the other case too.⁵ Obviously, the experience does not acquaint you with your mother in the hallucinatory case. It follows that it cannot do so in the perceptual case either. So now the idea that, when all goes well, your visual experience brings you in contact with people, things, and states of affairs in the world, looks deeply problematic.

I think the standard motivation for disjunctivism precisely resides in the alleged inability of conjunctive theories to establish (direct) contact between mind and world.⁶ On the disjunctive view, the answer to the question of whether you are hallucinating or perceiving your mother tells us something about the experiential episode you are undergoing, not merely about the aetiology of that episode. And since this answer is not independent of the actual presence or absence of your mother (the answer cannot be “perceiving” if your mother is absent), then we are able to view your experience as essentially connecting, in the perceptual case, with your mother. If your mother is not there, then neither is that specific type of experiential episode. The commonsense notion that your experience, in the perceptual case, acquaints you with or presents you with your mother herself now seems secure. At least so most disjunctivists seem to think.

If this way of looking at matters is right, then it seems that, on the conjunctive picture, experiences cannot themselves make perceptual contact with items in the world—they are not in themselves perceptive of such items. Conjunctivists can accept this and nevertheless argue that, contrary to the disjunctivist’s claims, to picture experiences as “falling short” of the world in this sense is not to picture experience as out of touch with the world in any epistemologically or metaphysically problematic sense (for a candid statement, see Crane 2006, p. 141; cf. Millar 2007). As already indicated, they can also point out that there are strong, independent reasons to be skeptical of the disjunctive theory. It would seem, then, that the dialectical situation is this: disjunctivism is prima facie an implausible view, and whatever appeal the view has depends on the disjunctivist’s ability to show that nothing short of a disjunctive view will enable us to make sense of the commonsense notion that when all goes well, our perceptual experiences make (direct) contact with particular worldly objects. Independently of some argument to the effect that conjunctive theories cannot make sense of our genuinely perceptual experiences being the sort of accomplishment we all pre-theoretically believe them to be—or some other equally overriding set of reasons—disjunctivism seems the wrong view to adopt.

As we will see next, it is doubtful whether Hopp adopts disjunctivism for anything like the reasons just outlined. The way he treats disjunctivists’ attempts to articulate those reasons suggests that he has little sympathy with their arguments.

3 Hopp’s Criticism of “The Relational View”

Hopp develops his so-called “moderate disjunctivism” in a critical confrontation with a more radical type of disjunctivism that he (following John Campbell, among others) calls the “relational view” (p. 149). What, precisely, Hopp takes the relational view to be committed to is not entirely clear to me, and for this reason I am not quite sure what Hopp’s own view amounts to either. First of all, Hopp says that “the relational view contends [that perception is] the sheer, content-free awareness of physical objects” (p. 190). But he also maintains that McDowell is an advocate of the relational view (namely of the “weird object” disjunctivist variety).⁷ I should have thought it fairly obvious that McDowell does not conceive of perceptual experience as “sheer, content-free” object-awareness. McDowell, after all, explicitly takes issue with Charles Travis and Bill Brewer over this, insisting, as against them, that experiences “directly bring objects into view […] precisely by having the kind of content they have” (McDowell 2008a, p. 10; cf. 2008b). And surely Hopp must agree that McDowell cannot be an advocate of the relational view if it involves the rejection of perceptual content, since Hopp dedicates much of Chaps. 3 and 4 to criticizing McDowell for holding the view that perceptual experiences have conceptual content (e.g., pp. 81–92). This is probably a minor point, though. More serious—and interesting—questions are raised by Hopp’s treatment of the main motivation for disjunctivism (McDowell’s in particular) and the idea that physical objects may be “constituents” of experience.

Hopp presents McDowell’s argument for disjunctivism as turning on a consideration of four collectively inconsistent propositions:

• (1) Intrinsically identical experiences have the same (kinds of) objects.

• (2) Hallucinations and perceptions are intrinsically identical.

• (3) The objects of hallucination are mere appearances.

• (4) The objects of perception are worldly facts. (p. 154)

Hopp comments that McDowell rejects (2)—this is precisely what makes his view a version of disjunctivism—whereas it is (3) that “should (also) be rejected” (p. 154). (The little parenthesized word indicates, of course, that Hopp embraces a type of disjunctivism himself.) Roughly stated, Hopp’s argument for rejecting (3) is that if the intentional objects of hallucinations were “mere appearances”—i.e., “weird objects”, not things likes chairs, tables and (pink) elephants—then they wouldn’t be or involve errors about what items are out there in the world. For “in order to nonveridically or falsely represent some object or fact, one’s experience or thought must minimally be about it” (p. 155; cf. p. 160). Hence McDowell’s argument fails to motivate a disjunctive view: “There might be a lot of good reasons to endorse disjunctivism, but the conjunction of (1), (3), and (4) is not among them” (p. 154).

Much, however, depends on whether Hopp is right to attribute (3) to McDowell. Granted, some of McDowell’s formulations do point in that direction, as Hopp usefully documents (see, e.g., p. 154). But I think it is clear that McDowell’s real worries have nothing to do with the question of whether or not hallucinations have “weird objects”. This is evident at various points throughout “Criteria, Defeasibility and Knowledge”, the paper from which Hopp quotes. For example, McDowell characterizes the sort of argument his disjunctivism is designed to resist as follows:

[S]ince there can be deceptive cases experientially indistinguishable from non-deceptive cases, one’s experiential intake—what one embraces within the scope of one’s consciousness—must be the same in both kinds of case. In a deceptive case, one’s experiential intake must ex hypothesi fall short of the fact itself, in the sense of being consistent with there being no such fact. So that must be true, according to the argument, in a non-deceptive case too (McDowell 1998, p. 386).

Pace Hopp, the point here is not that hallucinatory experiences “fall short” of the world in the sense of being “about” something altogether different (sense data or whatever), but simply that they fail to bring the world “into view”, or “acquaint” us with it. Remarkably enough, Hopp seems to miss this even as he quotes from some of the passages (including the one I have just quoted) in which McDowell articulates his real worries quite unambiguously. Hopp writes:

The problem with McDowell’s argument is that he treats the conjunctivist as committed to (3). Part of the reason is that he claims that, on such a view, a hallucination must “fall short of the fact itself” because one’s “experiential intake” is “consistent with there being no such fact.” […] But this is not the case. While the conjunctivist may be committed to the claim that (1) the occurrence of such an experience is consistent with there being no such actual fact corresponding to it, he need not be committed to the claim that (2) the correctness of the experience’s intentional content is consistent with there being no such fact. And the former claim does not entail that the experience is not about a worldly fact (pp. 154–155).

Clearly McDowell’s talk about a hallucinating subject’s “experiential intake” being consistent with there being no such object or fact as the subject seems to perceive has nothing to do with the second claim Hopp discusses in this quote. But it has everything to do with what I have called “the standard motivation” for disjunctivism. Qua hallucinating, we are not experientially aware of the things around us. How could we be? Disregarding cases of so-called veridical hallucination, when we hallucinate there isn’t an item of the sort that we (seem to) experience for us to be aware of. If perceptual and hallucinatory experiences are experiences of the same fundamental type, however, it seems we are compelled to accept that even in a genuinely perceptual case, our experience fails to constitute an awareness of the things around us. For how could the very same type of experience bring us in touch with—make us aware of—the world in the one case but not in the other? On this sort of (conjunctive) picture, the only real difference between the genuinely perceptual experience and its hallucinatory counterpart is that the former, but not the latter, is caused in the right way by an actually present object of the right sort. And that, McDowell urges, is not sufficient to make sense of experience as—in the good case—bringing objects into view.

It is initially somewhat surprising that Hopp spends so much energy dispelling the view that the intentional objects of hallucinations are non-worldly, “weird” objects, without ever getting around to discussing McDowell’s (as I see it) real motivation for advocating disjunctivism. Equally puzzling, at first, is Hopp’s discussion of another, closely related core idea of at least some versions of disjunctivism: the idea that, in the perceptual case, physical objects are “constituents” of the experience. Apart from the point, already touched upon, that the relational view construes perception as sheer, content-free object-awareness and thus fails to do justice to “the massively complex intentional acts and their contents that are required for perceptual consciousness” (p. 170), Hopp’s only objection to the “constituent” idea seems to be this: “If objects are constituents of our experience, in any remotely acceptable sense of ‘constituent’, then every part, feature or property of those objects must be a constituent of our experience” (pp. 170–171). Since, as Husserl has shown in detail, any perceptual experience of a physical object must be “inadequate”—must be “of” much more than is strictly given or presented—objects cannot be constituents of the experience. And so “the relational view is not right” (p. 171).

I find it hard to believe that clever people like John Campbell, Michael Martin, and John McDowell should have overlooked the fact that when I see a coffee mug, say, there are always aspects (rear side, innards, etc.) of it that are not strictly presented. And McDowell, for one, at least indirectly acknowledges the fact in question: “In a visual intuition, an object is visually present to a subject with those of its features that are visible to the subject from her vantage point”.⁸ But then perhaps it is not McDowell’s view that perceived objects are constituents of the experience anyway? If this is Hopp’s reply, then this constitutes one more reason to think that, ultimately, Hopp does not regard McDowell as an advocate of the “relational view” at all (pace pp. 153–154). However that may be, I strongly suspect that most if not all of those who do embrace the idea of objects as constituents of experience have in mind something that does not commit them to the view that physical objects can be adequately perceived. No doubt Hopp will object that, if so, their use of “constituent” cannot be even remotely acceptable, but I am not convinced. Once again, we are touching on something that is central to the motivation for disjunctivism, and once again, it is at first blush puzzling that Hopp seems to ignore it completely.

It is crucial to the disjunctivist that what the genuinely perceptual experience accomplishes is very different from what the hallucinatory experience does: the former is a presentation of worldly objects to consciousness, the latter is not. Now, as Martin (2006, p. 354) explains, if we take experiences “to be episodes or events”, then the disjunctivist will maintain “that some such episodes have as constituents mind-independent objects”. To see the reasoning behind this, ask yourself how, on a disjunctive picture—disregarding any non-psychological features of the situation—we are to understand the genuinely perceptual experiential event or episode. Obviously not along the lines of “it appears to you that a white coffee mug is on a table in front of you”. That is (roughly) the conjunctivist’s story about the experiential event. Rather, the event must be something like this: you are visually aware of the coffee mug. On what (I hope) is a fairly straightforward understanding of what it means for something to be a constituent of an event, the coffee mug is a constituent of the event of being-visually-aware-of-the-coffee-mug. Nothing is implied here about the adequacy or otherwise of the givenness of the mug; what is implied is that without the mug this type of experiential episode could not occur, for the simple reason that one of its constituents would be missing.⁹

What moves the disjunctivist to claim that objects are constituents of the veridical experience is again the central idea that nothing less will enable us to make sense of our experiences as putting us in touch with those objects. And as initially surprising as Hopp’s dismissive treatment of the claim is, surprise gradually gives way to the suspicion that he ultimately means to reject the standard motivation for disjunctivism. This impression is enhanced by a passage in Chap. 7, where Hopp seems to echo certain remarks Husserl sometimes makes. Consider the following quotes from the latter:

According to eidetic law it is the case that physical existence is never required as necessary by the givenness of something physical, but is always in a certain manner contingent [zufällige]. This means: It can always be that the further course of experience necessitates giving up what has already been posited with a legitimacy derived from experience. Afterwards one says it was a mere illusion, a hallucination, merely a coherent dream, or the like. […] Anything physical which is given “in person” [leibhaft gegebene] can be non-existent (Husserl 1983, p. 102).

Obviously, the foregoing characterization is not to be understood in the sense that there would pertain to the essence of every perception as such the existence of the perceived Object, the existence of that which stands there in the mode of presence in the flesh. In that case, talk of a perception whose object did not exist would indeed be countersensical; illusory perceptions would be unthinkable. […] To perceive a house means to have the consciousness, to have the phenomenon, of a house standing there in the flesh [leibhaft dastehenden]. How matters stand with the so-called existence of the house, with the true Being of the house, and what this existence means—about all that nothing is said (Husserl 1997, p. 12).

At first blush, Husserl here seems to side with the conjunctivist: even the genuinely perceptual experience, he seems to suggest, “falls short” of its object in the sense of being compatible with its non-existence. On closer inspection, however, remarks such as these seem ambiguous. On the conjunctivist interpretation, as just mentioned, Husserl’s point would indeed be that any possible perceptual experience—including the ones we enjoy if and when we genuinely perceive—is, qua experience, compatible with the non-existence of its object. But another interpretation is perhaps also possible, according to which Husserl’s point is merely that, for all we know as we are enjoying a putative perceptual experience, it is possible that the experience will be unmasked as a hallucination, or that it is in fact a hallucination, although it is not revealed as such. (Although if this is what Husserl means, his use of “perception” [Wahrnehmung] in the second quote is misleading.) The two interpretations are importantly different. The latter turns on the idea that any genuine perception can be indistinguishable from a hallucination or dream whose intentional objects do not exist, but no assumption is made about the nature or achievement of (genuinely) perceptual experience. The former precisely implies such an assumption, for on this interpretation even the genuinely perceptual experience is such that it—or an experience of the very same kind—could have been had even if its intentional object did not exist.

There is a strikingly similar passage in Hopp’s book. He writes: “the object perceived, or allegedly perceived, might always prove, in the further course of thought and experience, to have properties other than those it appeared to have, or even not to exist at all” (p. 200). Now, as it stands, this does not seem quite right. If I perceive (i.e., genuinely perceive) a white coffee mug, then a further course of experience might show that the mug has ceased to exist (if someone has smashed it to pieces, say), but it cannot reveal that it never did exist. When I perceive a coffee mug, the mug exists. Of course, if I only “allegedly” perceive it—have an experience “as of” a white coffee mug—the mug need not exist. Perhaps, then, Hopp means to be speaking not about the object perceived but only about the object allegedly perceived. Perhaps, in other words, the sentence should be read as saying: “the object perceived, or rather allegedly perceived, might always prove, in the further course of thought and experience, […] not to exist at all”. But then the point seems almost too trivial to bear repetition at this point in Hopp’s argument. Having an alleged perception as of a coffee mug is, on everyone’s view, compatible with the non-existence of the intentional object.

The quote is taken from Hopp’s discussion of Husserl’s theory of fulfilment, and this context indicates that Hopp’s point might be another one: even when I genuinely perceive (see) something like a coffee mug, my perception is, in Husserl’s terms, “inadequate” to its object. As already mentioned, my perception emptily intends “more” than what is strictly visually presented to me—an “inner”, a “rear side”, etc.—and it is always a possibility that those empty intentions will be frustrated if I decide to explore the mug further. I might walk around it only to discover that it was merely a mug façade, not an actual mug. Or indeed, I might discover that there is nothing there at all—I was merely hallucinating. So in the sentence I have quoted, Hopp is stating a corollary of the Husserlian insight into the inadequacy of perceptual experience—one of the insights allegedly contradicted by the relational view. But does his point ultimately come down to the (trivial) observation that I cannot be sure my alleged perception of a white mug is a perception of one, as opposed to an illusion or hallucination? Perhaps, but, first, this would be surprising given that Hopp’s intention seems to be to say something that holds for the genuine perception too. And, second, we don’t need the Husserlian insight into the “inadequacy” of perception to make us aware of the possibility that what we thought was a perception might be a dream or a hallucination—a familiar point to anyone who has read Descartes. Yet if this is not the possibility Hopp is referring to, then it seems he is saying that even the genuinely perceptual experience is, qua experience, compatible with the non-existence of its object. And that would place him squarely in opposition to precisely the sort of commitment most disjunctivists think is required of anyone who wants to make sense of experience as establishing direct contact with the world around us.

Let me note one final passage where, as I read him, Hopp unambiguously distances himself from what I have called the standard motivation for disjunctivism. After having rejected the idea—allegedly common to several disjunctivists—that hallucinations are not about the world, Hopp writes: “perception might just be a case in which the intentional content that it shares with a possible hallucination is satisfied. Such a view in no way entails that the intentional content falls short of the world in either case” (p. 161; my emphasis). As already mentioned, and as I’ll show in a little more detail in the next and final section, Hopp ultimately denies the conjunctivist claim that hallucinations and perceptions can have the same content. But in the quote he seems to suggest that his reasons for doing so have nothing to do with the idea that there is any sense in which perceptual experience, on the conjunctive picture, “falls short” of the world.

4 Manifolds and Disjunctivism

Putting all the pieces of (circumstantial) evidence together, then, I conclude that Hopp rejects the standard motivation for disjunctivism. This raises the question of what does motivate Hopp to embrace what he calls a “moderate” version of the theory. I must confess that I am far from sure what the answer is. What seems clear enough is that Hopp takes his lead from (A. D. Smith’s interpretation of) Husserl’s thoughts on intentional horizons and “manifolds”. The basic idea, as I understand it, is this. Each genuinely perceptual experience of a particular object has, as part of its content, a “‘noetic X’, in virtue of which it succeeds in picking out its object and no other” (p. 177). In other words, two subjectively indistinguishable experiences of two identical white coffee mugs have different content. For to one experience belongs a “noetic X” that picks out coffee mug A, while the other experience has an “X” that singles out another mug, B.

This might sound purely ad hoc, but the idea of the determinable X is itself explained by the notion of a “manifold”. Each individual worldly object has its manifold—its ultimately harmonious system of possible experiences of that object.¹⁰ The manifolds of two different objects have no possible experiences in common. Manifolds track, as it were, their individual objects through space and time; type-identical, but numerically different objects are tracked by different manifolds. If an object A is moved from one room to another, only experiences presenting the object in its new location will belong to its post-move manifold. And the only way to keep having experiences belonging to its manifold during and after the move—assuming there are no transparent walls, CCTV footage, or the like, to allow one to see what goes on in the neighbouring rooms—would be to engage in movement oneself, that is, to follow the object. On the other hand, if my coffee mug changes neither size nor position—mugs usually neither shrink, grow, nor move about on their own—then the activity of moving away from it must yield experiences in which the mug takes up increasingly smaller portions of the visual field; if this is not what I experience, then my experiences do not belong to the mug’s manifold. Finally, for an experience to belong to the mug’s manifold, certain counterfactual dependencies must hold: for instance, it must be the case that, were I to move away, the motionless mug would take up a smaller portion of my visual field.

It follows from this that hallucinations do not belong to any of the manifolds of real objects. For, assume that they do. Then, if I am hallucinating my coffee mug, that coffee mug must be present in front of me in the location where it seems to me to be. For if the object was elsewhere—say, in the next room—my current experience would by definition not belong to this object’s manifold. So the hallucination would have to be (at the very least partly; see footnote 10) veridical, it seems. Either its being so is a pure coincidence, or there is some systematic relation between what happens to the object, to me, or to my relation to it, and what I experience, such that I would continue to have veridical experiences if I moved around it, followed it as it was moved to an adjacent room, etc. In this latter case, though, it seems that what we have imagined is not really a case of hallucination, but actually a case of (perhaps non-standard) visual perception (p. 185; cf. Lewis 1980). But if, on the other hand, it is simply a coincidence that I happen to have an experience that matches what is actually there, then the counterfactual dependencies that must be in place for an experience to belong to an object’s manifold would not hold. It would, then, not be the case that had I turned my back to the mug, I would have ceased to see it, and had I moved closer, it would have taken up a larger portion of my visual field, and so on.

As Smith (2008, p. 330) points out, disjunctivism is now only one small step away. That step is the claim that each perceptual experience is essentially a member of whatever manifold (if any) it is a member of. For it is now clear that if I am having a veridical experience E of an object o, then E is essentially an experience of o and thus not an experience that I could have enjoyed had o not existed. Since this goes for all genuinely perceptual experiences, and since no hallucinations belong to an object’s manifold, perception and hallucination “differ intrinsically” (p. 188). According to Smith, this is precisely the conclusion Husserl draws (or is at least committed to) (Smith 2008, p. 331). Hopp clearly follows suit. What remains less clear to me is what, ultimately, motivates him to do so. As we have seen, he seems entirely unmoved by what I called the standard motivation for disjunctivism. Yet if the dialectical situation in the disjunctivism debate is anything like the way I portrayed it in Sect. 2 of this paper, then we need strong reasons to prefer the prima facie implausible disjunctive theory to the more plausible conjunctive alternatives; and it is not obvious to me that Husserl’s theory of “manifolds” fits the bill. If, on the other hand, someone believes the dialectical situation is not as I have described it, then they should explain why not.

As far as I can tell, Hopp offers us neither of these things. Nor does he engage directly with the usual objections to disjunctivism. Hopp’s adoption of “moderate disjunctivism” therefore seems insufficiently motivated.¹¹