1 Introduction

1.1 Overview

One of the central debates, if not the central debate, in contemporary philosophy of perception concerns whether veridical perceptual experience and sensory hallucination belong to the same fundamental category. The stakes of the debate are high. Attempts to address the matter are at the same time defenses of particular views of the nature of perceptual experience. Readers of Edmund Husserl’s works will recognize, given the prominence of reflection on the nature of perceptual experience in his works, that this issue presents a prime opportunity for mutual enlightenment. This debate may provide a novel angle through which to reconsider Husserl’s theory of perceptual experience and an inroad for then bringing his distinctive and far from fully appreciated insights about perceptual experience to bear on a weighty issue of present concern.

My interest in what follows is to remove a potential obstacle for putting Husserl in conversation with the prevailing views about whether veridical perceptual experience and sensory hallucination belong to the same fundamental category. Husserl’s mature philosophical outlook is quite foreign to that of contemporary philosophers of perception. Husserl scholars have recently raised the question of whether Husserl’s employment of phenomenological reduction in developing an account of perceptual experience opens an unbridgeable divide between his resulting theory and what is now on offer from naturalistically inclined philosophers of perception for whom metaphysical realism appears to be a non-negotiable starting point. This is a serious obstacle for the sort of mutually enlightening discourse just mentioned.

After providing background about the significance of the theory of perceptual experience for Husserl (§ 1.2), sketching in broad strokes the contemporary debate about the relation between veridical perceptual experience and sensory hallucination (§ 1.3), and refining the point I aim to address presently (§ 1.4), I argue in the bulk of what follows that the obstacle just mentioned is surmountable (§§ 2–4). I do not take a stand about how Husserl’s theory of perceptual experience compares to familiar views in the contemporary debate. Instead, I take the preliminary step of clearing a major hurdle standing in the way of making such a comparison in a principled way.

1.2 Husserl’s Concern with Perceptual Experience

Husserl’s account of perceptual experience is central and foundational to his broader philosophical program. He sees the task of phenomenology as that of making sense of the relationship between experience, meaning, and object (Husserl, 1999, 19/17; Hopp, 2020, xvii-xix, 50–51).Footnote 1 The locus of investigation for this triad is the intentional experience, whose basic form is the presentation (Vortstellung), and the perceptual presentation more specifically. Whereas other kinds of intentional act are in one way or another “founded” or existentially dependent on perceptual experience, the latter is “straightforward,” being neither founded on nor reducible to any other kind of intentional act (Husserl, 2001a, §§ 27, 47). So, perceptual experience is fundamental for Husserl.

As for the centrality of perceptual experience to his project of developing a transcendental phenomenology, it will have to be enough for now for me to gesture toward the critical role that discussion of perceptual experience plays in the “pre-considerations” leading up to Husserl’s opening up of the domain of pure consciousness in Ideas I (Husserl, 2014, §§ 41–46). It is in the analysis of perceptual experience that Husserl first catches a glimpse of the more general fact of the inadequacy of all our intentional relations to a mind-transcendent reality, a point that serves as a springboard for the “[r]adical considerations […] necessary in order to press through to the recognition that there is something like the field of pure consciousness in general” (Husserl, 2014, 96/92), and so helps reveal the proper domain of inquiry for transcendental phenomenology.

Naturally, given the fundamentality and centrality of perceptual experience, Husserl devotes a great deal of attention to trying to capture its essence through phenomenological description. These analyses are scattered throughout Husserl’s corpus. Maybe the most extended treatments occur in Wahrnehmung und Aufmerksamkeit, Thing and Space, Ideas II, the Lectures on Passive and Active Synthesis, and Experience and Judgment. In those works and others Husserl develops a comprehensive account of what the nature of perceptual experience is. In doing that he also says a great deal about the nature of perceptual error, especially in Wahrnehmung und Aufmerksamkeit (Husserl, 2004, 82, 125–129, 196–197 342–344), the Lectures on Passive and Active Synthesis (Husserl, 1970/2001b, §§ 5–15), and Experience and Judgment (Husserl, 1973, § 21).

1.3 Perceptual Experience in 20th -21st Century Anglophone Philosophy

For a Husserl scholar, what I’ve just related makes it exciting to observe the way philosophy of perception has become a major area of study over the last three decades and, moreover, to see how prominent within that discourse the issue of perceptual error has become. The opportunity has not gone unnoticed, a point I’ll come back to in a moment.

The story of philosophical theories of the nature of perceptual experience in 20th and early 21st century anglophone philosophy is too complex to canvas here.Footnote 2 Sense datum theories were popular early in the 20th century.Footnote 3 Their attractiveness brings us already to the issue of perceptual error. Sense data were introduced initially as placeholders for whatever it is we stand in a relation of conscious awareness to in perceptual experience. The possibility of hallucinatory and illusory experience, to some minds, suggested that we should not equate sense data with actual mind-transcendent particulars. They should be equated, instead, with mind-dependent, irreducibly mental entities, sensations, through which we indirectly come to be aware of the world around us.

One major downside of that approach, however, is having to posit irreducibly mental, i.e., non-physical, sensations. Not only did philosophers in the latter part of the 20th century for the most part prefer to avoid that result, but they also began to question the underlying conception of perceptual experience as a matter of standing in a relation of conscious awareness to something, whether it be a concrete, spacetime object or a non-physical, mind-dependent sensation. Once perceptual experience is conceived of in non-relational terms, the concern about illusion and hallucination begins to lose its bite.

If perceptual experience isn’t a way of standing in a relation of conscious awareness to something, then what else could it be? The most common reply has been and continues to be that it consists of representing things. Perception is then taken to be just another kind of thought, one with a distinctively sensory quality to it. And just like thought generally, it is explained in terms of its content, whether that be propositional, conceptual, or otherwise. The content of an experience is its meaning, determining the things it is about and characterizing those things as being some way or another, that is, construing them as having this or that perceptible property.Footnote 4

One of the advantages of this type of account is supposed to be the way it explains perceptual error. If I misperceive the shape or color of an object, that’s because the content of my perceptual experience fails to match the way the object actually is. Similarly, hallucination, when I seem to perceive something that’s not really before me at all, is taken to be a matter of having an experience with content that singles out an object that is not presently there to be perceived. The content makes the experience the way it is phenomenally, and the content can be tokened regardless of whether it really captures the way the object is or whether it picks out something available to be perceived in the first place. If that is right, it follows that veridical and non-veridical (i.e., illusory or hallucinatory) perceptual experience are basically the same kind of experience. What distinguishes them is not anything about their intrinsic nature, but rather the contingent relation they happen to stand in with the perceiver’s surroundings.

Despite the appeal of that view, there have been calls to return to the older, relational take on the nature of perceptual experience. Self-styled naïve realists or, equivalently, relationalists, propose that perceptual experience is standing in a conscious relation to something and that this something is always a concrete object, property, or event and not an irreducibly mental sensation.Footnote 5 Sense datum theorists, recall, avoided this option, finding it untenable because of the difficulties that come with explaining the nature of perceptual error on this scheme. If I misperceive a yellow object as green or hallucinate a yellow object when no such object lies before me, I evidently do not stand in any relation at all of conscious awareness to an instance of green or a yellow object, respectively.

Naïve realists are mostly prepared to accept this and amend the view of perceptual experience I have just related to be a disjunctive one.Footnote 6 A perceptual experience is either veridical (or possibly illusory) and so a relation of conscious awareness to a concrete worldly entity or it is non-veridical (or possibly just hallucinatory) and so understood differently. There is disagreement about just how to understand the nature of hallucination but broad agreement that, whatever its nature, hallucination is something essentially different in kind from veridical perceptual experience. The comparative lack of theoretical parsimony of naïve realism is the price paid for its purported advantages in accounting for the transparency of perceptual experience (Kennedy, 2009), getting the comparative phenomenology of perception and imagination right (Martin, 2002), grounding our use of demonstrative concepts (Campbell, 2002), securing empirical knowledge (Campbell & Cassam, 2014), and, among other things, providing an antidote to skepticism (Johnston, 2011).

In the current debate about the nature of perceptual error and hallucination, in particular, the two views that get the greatest amount of attention are the representational and the naïve realist accounts the gist of which I have just described. The labels for the corresponding views of perceptual error are, respectively, conjunctivism and disjunctivism. The disjunctivist, as I just related, holds that perceptual experience is a disjunctive category. Both veridical perception and hallucination fall under it, yet the two do not share a common nature. The conjunctivist denies this and maintains that perceptual experience is a unified category, with both veridical perception and hallucination sharing the same essential, defining characteristics.

The correspondence is not perfect, since some say the representational content of perceptual experience is object-involving, leading them to offer a similar account of perceptual error as naïve realism provides (Brewer, 2000). Another complication is that some naïve realists maintain that hallucination is basically the same as illusion and that illusion is basically the same as veridical perceptual experience (Ali, 2018). Some naïve realists have also argued that there is in fact a common essential characteristic shared by hallucination and veridical perceptual experience (Johnston, 2004). However, such complications—and others besides—have not had much of an impact on the discussion of how Husserl’s view relates to the debate as I am now presenting it, so there is no need to dwell on them. All that matters, and this will be important later, is that we recognize representationalism and conjunctivism are not equivalent notions and neither are naïve realism and disjunctivism, despite the close association.

1.4 Husserl and the Debate About Hallucination

Husserl scholars have not passed up the chance to reexamine Husserl’s view of perceptual experience and perceptual error in light of the peculiar concerns raised in the ongoing debate whose main contours I have just sketched. Some commentators think Husserl’s views on perceptual experience and hallucination entail a version of disjunctivism (Smith, 2008; Hopp, 2011), others a kind of conjunctivism (Romano, 2012; Bower, 2020), and still others a novel view fitting neither description exactly (Staiti, 2015; Zahavi, 2017; Drummond, 2012). Søren Overgaard (2018) and I (Bower, 2020, 551–569) have presented critical reviews of how this discussion has unfolded. While Overgaard remains uncommitted, his discussion ends on a sympathetic note for disjunctive readings. I, on the other hand, defend a conjunctive reading. Overgaard and I nevertheless agree that Husserl belongs in one of these two camps and that attempts to locate Husserl’s view outside of those options are either fatally flawed or too underdeveloped to take seriously.

My focus here will be on the neither-conjunctivist-nor-disjunctivist readings of Husserl. I will not revisit the readings of this type cited in the preceding paragraph. I have nothing to add to Overgaard’s take or my previous take on them. I focus instead on a concern raised by Cimino (2021, 750–756) and Doyon (2022, 175–177). They note that there is a serious—although Cimino himself thinks, not decisive—obstacle to any interpretation of Husserl as a disjunctivist or conjunctivist. What stands in the way is that Husserl’s theory of perceptual experience is developed within the point of view of phenomenological reduction, which bars phenomenological reflection from appeal to any positive epistemic commitment pertaining to mind-transcendent reality, and the typical conjunctive and disjunctive theories of perceptual experience both operate squarely within the confines of the natural attitude and presuppose some form of metaphysical realism. In what follows I elaborate the reasoning behind this concern and argue that the obstacle is only apparent, and, at least when it comes to this specific angle on the problem, Husserl may well turn out to hold a conjunctive or disjunctive view.

2 A Divergence in Theoretical Starting Points

Husserl’s account of perceptual experience and error may seem to be worlds apart from any form of conjunctivism or disjunctivism when you recognize that their respective philosophical starting points are not just distinct, but diametrically opposed. The thought is this. If conjunctivism and disjunctivism are necessarily premised on an assumption and Husserl’s view is explicitly formed so as not to rely on the truth of that assumption or to rely on some other assumption that contradicts or entails the contradiction of the former, then Husserl’s view must be distinct from and incompatible with either of these views.

What exactly is this difference in starting point? Husserl carries out his phenomenological investigations within the methodological confines of the epochē. This is peculiar to Husserlian phenomenology. As Husserl explains in Ideas I, to exercise epochē is to systematically refrain from making theoretical use of any of your convictions about the real existence or actuality of mind-transcendent entities (Husserl, 2014, §§ 30–32). Those convictions may take the form of particular explicitly held beliefs about the existence of this entity or that kind of entity or they may be more global but implicit attitudes of taking for granted the existence of the world you are constantly confronted with in experience. When you perform epochē, you epistemically disconnect from any of these convictions, which Husserl collectively refers to as the natural attitude. They cease to carry any evidential weight in your theorizing. They may in some sense regain some evidential significance and give rise to knowledge, but only on the basis of evidence phenomenologically internal to these experiences themselves (Husserl, 1999, 29/23, 33/26).

No restriction like that is in play for extant versions of conjunctivism and disjunctivism. As Doyon correctly recognizes, parties to the ongoing debate characteristically take for granted a kind of metaphysical realism (Doyon, 2022, 175). Cimino describes their implicit attitude as one in which “the skeptical-transcendental problem” that motivates Husserl’s deployment of the epochē “is evaded” (Cimino, 2021, 748). The conjunctivist and disjunctivist table the issue of skepticism and operate within the natural attitude without calling it into question. They take for granted that veridical perception is of actually existing mind-independent objects. Both conjunctive and disjunctive views typically assume that perceptual experience involves causal relations between mind-transcendent reality, the physical human brain, and the conscious mental life of the perceiver.

It will help to be more specific about the metaphysical realist underpinnings of the opposing views of conjunctivism and disjunctivism. Recall again the relevance of causal relations between perceiver and perceived for the two views. Conjunctivists, in particular, rely on this fact to explain the difference they locate between veridical perceptual experience and hallucination. They maintain that veridical perception involves a certain causal connection between mind and world that is absent in hallucination. Disjunctivists, on the other hand, have other reasons for drawing on metaphysical realism. They tend to hold that the relation to the perceived object in veridical perceptual experience is due to an internal connection between experience and object that accounts for the very nature of the experience. Some think that the relation is due to the semantic content of the experience and others deny semantic content plays any role and deem the perceptual relation to be sui generis. Either way, an experience without that internal connection would not just be non-veridical, it would be another kind of experience.

There is good reason, then, to suspect that Husserl’s account of perceptual experience could not in principle be reconciled with either conjunctivism or disjunctivism. It is not just that these two views do not explicitly put out of play the epistemic commitments definitive of the natural attitude. Apparently essential and definitive elements of the two views are elaborated overtly in terms of a positive epistemic commitment to the existence of a mind-transcendent world.

2.1 Starting Points and End Points

That Husserl’s account of perceptual experience, on the one hand, and those contained in conjunctive and disjunctive views, on the other, tend to diverge in this way—Husserl employing epochē and conjunctivists and disjunctivists helping themselves to the natural attitude—does not suffice as a reason for thinking Husserl can be neither a conjunctivist nor a disjunctivist. Perhaps Husserl could not, for the reason just mentioned, sign off on any particular variant of these two views currently on offer. But we should not expect for Husserl’s view to be a perfect match with any presently available view in the first place. Rather, what we should be determining is whether Husserl’s view satisfies one of the two general descriptions of which these views are variations.

Conjunctivism is just the view that veridical perceptual experience and hallucination have the same underlying nature and defining attributes. On this view, whatever sets apart veridical perceptual experience from imagining, remembering, thinking, having an emotion, feeling pain, etc., is also what sets apart hallucination from those kinds of experience. And disjunctivism involves attributing distinct underlying natures and defining attributes to veridical perceptual experience and hallucination, so that what sets either one apart from the experience of imagining, remembering, thinking, having an emotion, feeling pain, etc., is some distinct property not shared by the other.

Framed in that way, there is a great deal of latitude for how precisely these views might be developed, a fact that is apparent from the considerable variation in how they have in fact been defined by particular proponents of them. For instance, disjunctivists disagree not only about whether the phenomenal character of hallucination can be positively characterized, but also about whether hallucination has phenomenal character at all. Disjunctivists disagree, further, about the nature of the perceptual relation, e.g., about whether it is grounded in the tokening of a special kind of object-involving content or is a sui generis type of relation. The divergence in how to conceive the terms the debate centers on is at least as dramatic between disjunctivists and conjuctivists. They often exploit their accounts of perceptual error, after all, as a way to defend their peculiar views about the nature of perceptual experience and hallucination. The discourse carries on, in other words, despite the fact that, within at least one of the camps and between the two of them, there is little common ground about just how to understand key notions involved in the debate like that of veridical perception and hallucination.

Note, further, that it is not as if Husserl refuses to deploy the same notions made use of by conjunctivists and disjunctivists. Everyone will grant that Husserl still freely speaks of veridical perception, illusion, and hallucination, even if his terminology is not the same and his particular conception of these ideas differs, perhaps dramatically, from those of the typical conjunctivist or disjunctivist. The upshot is that even if it turns out that, given his abstention from the natural attitude, Husserl has to offer a highly idiosyncratic and non-standard analysis—one, to be specific, that rejects or refuses to endorse metaphysical realism—of the nature of veridical perception and hallucination, it is still entirely possible that his view may nevertheless count as either a kind of conjunctivism or disjunctivism.

2.2 Conjunctivism/Disjunctivism Without Metaphysical Realism

There is another way to see what is wrong with the idea that, because of their antithetical philosophical starting points, Husserl’s account of perception belongs in an entirely different class than that of conjunctive and disjunctive accounts. The key premise seems to be that if Husserl is not committed to metaphysical realism and conjunctivists and disjunctivists both are, then Husserl’s view can’t be either a version of conjunctivism or of disjunctivism. Now, the claim ought to hold good if generalized somewhat. It is not Husserl’s abstention from metaphysical realism in particular that is at issue. If correct, the same reasoning must apply to other views similarly uncommitted to metaphysical realism. On the other hand, if there exists an anti-realist account of perceptual experience that fits our generic characterization of conjunctivism or disjunctivism, then the key premise I have just identified should be rejected.

Is there such a view? Here I would point to George Berkeley’s theory of perceptual experience as an example. Berkeley famously holds that for concrete material objects that esse est percipi, that is, to be is to be perceived (Berkeley, 2017, 44). As he explicates it, this thesis means perceptible objects just are ideas “in” our mind.Footnote 7 You might think that means there could be no way on this view to draw a distinction between veridical and non-veridical perception and that, therefore, there could be no such thing as a hallucination if Berkeley were right. Yet, that is not the conclusion either Berkeley’s or his interpreters have drawn.

Berkeley maintains that even if all ideas exist necessarily by being perceived, that we can nevertheless distinguish between real and illusory ideas and proceeds to offer criteria for how to do that (Berkeley, 2017, § 34).Footnote 8 Howard Robinson remarks on this issue as it concerns Berkeley’s view of perception that “metaphysical mind-independence is not needed to guarantee objectivity” (Berkeley, 1996, xiv). The reality or objectivity Berkeley and Robinson, respectively, speak of is supposed to explain possible differences between how things perceptually seem and how they are, and so also the possibility of non-veridical perception, without taking on board any kind of metaphysical realism. Rather than basing the distinction between veridical and non-veridical perception on how such experiences relate to a mind-independent reality, Berkeley proposes a criterion concerning how experiences like these relate to one another (Dicker, 2011, 155, 240–241).

Despite being an avowed anti-realist, then, Berkeley has the resources for drawing a genuine distinction between veridical and non-veridical perceptual experience. And that is enough for us to be able to legitimately inquire further about whether his view qualifies as a conjunctive or disjunctive one, as at least one commentator on Berkeley has done (Richmond, 2009, 53–54). We do not need to let the details detain us. The important thing is to recognize that if perceptual error is possible, then it is appropriate to ask, in the case of hallucination, whether that type of experience is basically the same in nature as veridical perception or not. If the two are the same at bottom, then the account is conjunctive and if they are basically different, then the account is disjunctive. Richmond has proposed that the former option is the one that should inform our reading of Berkeley.

The price of admission to the contemporary debate about hallucination is not conceptual common ground or a shared metaphysical outlook. Rather, the goal is to work toward an understanding of what it means for a perceptual experience to be veridical or non-veridical and whether that difference marks, at least for veridical perception and hallucination, a point of substantive and fundamental divergence or not. So, Husserl’s performance of phenomenological reduction does not absolve him from being a party to the debate at all. Of course, he could not agree to any version of conjunctivism or disjunctivism that takes metaphysical realism for granted, just as Berkeley could not. Nevertheless, his view may end up fitting the generic description of being disjunctive or conjunctive, again, just as Berkeley’s seems to do.

2.3 Disjunctivism and Naïve Realism

The conclusion I have drawn in §§ 2.1 and 2.2 might be resisted by singling out disjunctivism to further clarify the nature of the contention about the methodological between Husserl’s view and those of typical conjunctivists and disjunctivists. As I related in § 2, many opt for disjunctivism because they are naïve realists and take naïve realism to be incompatible with conjunctivism. And the core of naïve realism is the idea that perceptual experience consists in a relation of conscious awareness to an actually existing object. Husserl’s view, due to its abstention from the natural attitude, apparently cannot accept a metaphysics of perceptual experience like that, since the epochē forbids making theoretical appeal to attitudes countenancing the real existence of their objects. Naïve realism and disjunctivism, taken as a package deal, are thus in principle not amenable to being refashioned sans metaphysical realism.

None of what I have just related justifies the main point of contention at present, which is that Husserl’s view cannot be identified with any form of conjunctivism or disjunctivism. If anything, it might be used as prima facie evidence for thinking Husserl is a conjunctivist. To secure the point of contention, it would be necessary to show further that conjunctivism, too, is incapable of any modification that sheds its commitment to metaphysical realism. But as I indicated earlier when appealing to Berkeley’s view of perceptual experience and error (§ 3.2), logical space has room for a conjunctive view not burdened with metaphysical realism, even if this turns out not to be the correct view.

Setting that matter aside, I doubt that the first step of the argument, the point about disjunctivism and naïve realism, is secure. As formulated, and as Doyon observes (Doyon, 2022, 181, n. 15), it does not apply to disjunctivism per se, but to disjunctivism combined with naïve realism or any view that takes perceptual experience to consist of a relation to the perceived and the perceived to include mind-transcendent concrete particulars. If there are motivations for disjunctivism that are independent of any commitment to naïve realism, then that again shows there is greater leeway in the relevant domain of logical space than there might appear at first. One might accept a representational view of perceptual experience that admits the possibility of non-veridical perception (i.e., illusion) but that nevertheless takes hallucination to be a basically distinct kind of experience, perhaps on phenomenological or empirical grounds. Regarding the latter point, one might be moved by the arguments of Keith Allen that hallucination is best understood as a species of imagining (Allen, 2015). Søren Overgaard and Julia Jansen both tentatively propose a reading of Husserl broadly reminiscent of the view I’m describing (Overgaard, 2018, 43, n. 35; Jansen, 2016, 75), although Jansen does not regard her view as supporting the disjunctive reading of Husserl I am now gesturing toward. I do not mean to endorse that reading, however. I call attention to it only to suggest that it would be premature to rule out the possibility of a Husserlian form of disjunctivism.

A.D. Smith’s disjunctive reading of Husserl is, I think, likewise immune to the concern about naïve realism (Smith, 2008). Again, the crucial point is that disjunctivism and naïve realism are not equivalent notions and accepting one doesn’t entail accepting the other (see § 1.2 above). Smith does not take Husserl to be a disjunctivist on the grounds that Husserl’s account of perceptual experience is a form of naïve realism. Smith does not attribute to Husserl the view that perceptual experience fundamentally consists in a relation of conscious awareness of a perceiver to a perceived object. Rather, he builds his case for a disjunctive reading of Husserl based on a reflection on Husserl’s notions of perceptual horizon and of perceptual manifold. And that reflection, moreover, seems to respect the methodological stricture of phenomenological reduction and so not to run afoul of the underlying concern about disjunctivism.

3 A Complication Concerning Husserl’s Approach

There is a further problem with the contention that Husserl’s methodological commitment to phenomenological reduction makes his view incomparable to either conjunctivism or disjunctivism. The issue is that Husserl’s account of perceptual experience may not be as intimately connected to the phenomenological reduction as one might suppose. Up to this point I have assumed an intimate connection between Husserl’s account of perceptual experience and the performance of phenomenological reduction. There are good grounds that I will explore now for doubting the connection is so intimate.

If you attend to Husserl’s own practice, you find that in some places he develops the foundational elements of his account of perceptual experience prior to performing or without having performed the phenomenological reduction (§ 3.1). In some later texts he modifies his approach to suggest that a quasi-reduction is needed for properly grasping the nature of psychological phenomena like perceptual experience, but this does not obviously have the consequences one would need to draw to show Husserl’s account of perceptual experience is incommensurate with either disjunctivism or conjunctivism (§ 3.2).

3.1 Husserl’s Reflections on Perceptual Experience Independent of the Reduction

Husserl’s Ideas I is a programmatic work not dedicated so much to developing a theory of perceptual experience as to spelling out his vision for phenomenological philosophy generally. Nevertheless, reflection of perceptual experience plays a prominent role in doing that for him, especially in §§ 35–46, which lay the groundwork for carrying out the phenomenological reduction in Chap. 3 of Part 2 of Ideas I, which picks up with § 47. The sequencing of the train of thought in this work thus indicates that the account of perceptual experience found in §§ 35–46 does not presuppose epochē or phenomenological reduction. Husserl, moreover, encourages us to follow along with him in these sections in such a way that “we do not trouble ourselves with any phenomenological epochē” (Husserl, 2014, 60/69). This is a fairly well-recognized feature of the relevant passages of Ideas I (Jacobs, 2017).Footnote 9

What Husserl says about perception in the relevant pre-reduction sections of Ideas I (Husserl, 2014, §§ 34–46) covers a substantial portion of his overall view of the matter. It is supposed to show that perceptual experience is a kind of intentional state (§§ 34, 36), that it directly presents concrete particulars (§§ 39, 43), that it presents them “inadequately” (§§ 42, 44), that the presentation of mind-transcendent objects is inherently fallible (§ 46), that perceptual experience includes a mind-dependent sensory component (§ 41), and it is supposed to show that these are necessary truths revealing the basic nature of perceptual experience (§ 34). Husserl retracts none of these points after performing phenomenological reduction. He adds to the account (e.g., § 85, 97), but subtracts nothing from it. Most importantly, Husserl’s view about perceptual error is already at least partly contained in these sections (§§ 42, 44, 46). It is critical, even indispensable setup for his attempt to reveal the domain of pure consciousness in later sections.

I take this to show that grasping the nature of perceptual experience as Husserl conceives it does not presuppose phenomenological reduction and that the two issues are orthogonal. If that is correct, then Husserl’s commitment of phenomenological reduction presents no obstacle to substantive comparison between his view of perceptual experience and that of those who abstain from phenomenological reduction.

The point I have just made is not idiosyncratic to the way Husserl formulates his views in Ideas I. Elsewhere, in Phenomenological Psychology, Husserl similarly discusses the nature of perceptual experience at length (Husserl, 1977, §§ 28–36), yet without “surrendering the natural standpoint,” that is, without epochē and phenomenological reduction (150/115). It is true that Husserl subsequently says that the phenomenological study of perceptual experience, presumably including the sections just cited, involves phenomenological reduction, if only in some implicit way (188/144). That apparent reversal can be explained in a way that does not, I think, contravene my present contention.

Husserl is describing the same path he traversed in Chaps. 2 and 3 of Part 2 of Ideas I. He is not actually performing the phenomenological reduction in §§ 28–36 of Phenomenological Psychology in the same sense as he is in Chap. 3, Part 2 of Ideas I. Rather, his point that properly uncovering the essence of perceptual experience, as the joint upshot of the restriction to intuitive evidence and the subject matter disclosed therein, entails taking on an attitude that if extended can “lead you so far that you can see the all-inclusive nexus of pure subjectivity as a realm of its own, as a self-contained world, and as the field of tasks for a pure psychology” (Husserl, 1977, 195/149). It can then serve as an enabling condition for transcendental reduction (which I take him to be describing in the last clause of the quotation just given), just as Chap. 2 does for Chap. 3 of Ideas I Part 2. The scope of the phenomenological reduction is, after all, considerably broader than what the phenomenological treatment of perceptual experience concerns (Husserl, 1977, 193/147).

3.2 The Psychological Epochē

In the Crisis Husserl reflects at length on the relationship between the study of (perceptual) experience and performance of phenomenological reduction (Husserl, 1970, §§ 69–72).Footnote 10 There he seems to have modified his views as contained in texts like Ideas I or Phenomenological Psychology or at least offered a markedly different redescription of them. This is apparent in his comment that “Psychology”—understood as the study of conscious, intentionality-laden mental life—“requires epochē” (Husserl, 1970, 252). The nature of this epochē or reduction, as Husserl notes, is abstractive. It is a methodological precept, or collection of precepts, for how to direct our thought—indicating what we ought to attend to and what we ought to refrain from attending to—in reflecting on the nature of perceptual experience and conscious psychological phenomena more generally.

Crucially, the “phenomenological-psychological epochē” Husserl considers in the Crisis is distinct in a very basic way from the transcendental reduction he introduced in Ideas I. He says of the psychological epochē that it is not “genuinely transcendental” (Husserl, 1970, 262).Footnote 11 That is because, as he puts it, “It would naturally be wrong to say that there can be no psychology as a science on the ground of the pregiven world” (257). Indeed, he adds, “What interests him [the psychologist] is […] [that] which exists in the world” (263). The psychological epochē does not reveal pure consciousness as giving the world its “meaning and validity” like the transcendental reduction does (Husserl, 1970, 262; Husserl 1997b, 340–341/246). It falls short of putting the “given” character of the world itself in brackets. That means the psychological epochē does not involve leaving behind metaphysical realism, even if its “pure” elaboration would “necessarily” lead to the transcendental (Husserl, 1970, 256). Because, as we have been considering, metaphysical realism appears to be the obstacle to positively comparing Husserl’s view to either conjunctive or disjunctive views of the nature of perceptual experience, the existence of a psychological epochē provides no reason to abstain from doing so.

Husserl makes a further germane point in his discussion of the psychological epochē. He posits an “identity” or strictly “parallel” relationship between psychology and transcendental phenomenology (Husserl, 1970, § 72). Husserl thinks that in studying conscious mental life by means of the psychological epochē eventually—even inevitably—leads you to the standpoint of transcendental phenomenology by “taking leave of the ground of the world” (Husserl, 1970, 263). The pertinent implication is that nothing about the ontology of conscious experience gained under the auspices of the psychological epochē is diminished, altered, or lost upon taking on the transcendental standpoint. In the Amsterdam Lectures he goes so far as to say that the “whole of mental content” discerned in the former “remains conserved” in the latter (Husserl, 1997b, 342/247). As this whole contains Husserl’s preferred account of the nature of perceptual experience, it follows the question of the nature of perceptual experience can be addressed independently of the transcendental-phenomenological reduction.

4 Dialogical Implosion

So far, I have been trying to show that Husserl’s commitment to phenomenological reduction is by itself not reason to hold that his account of perceptual experience is incommensurate with conjunctive and disjunctive views of perceptual experience. I have argued that his account of perceptual experience may not presuppose performance of phenomenological reduction (§ 3) and that, even if it did, the relevant conclusion would not follow (§ 2).

Reinforcing the argument of § 2 above, I will now develop a reductio ad absurdum of the idea of using phenomenological reduction to drive a wedge between Husserl’s account of perceptual experience on the one hand and conjunctive and disjunctive accounts on the other. Analogous arguments in the very same spirit could be put together to reason that Husserl’s view is incommensurate with anything on offer in other philosophical debates in which the norm is to take metaphysical realism for granted. For instance, it would be impossible to locate his view in relation to other views about the nature of universals or abstracta, of meaning, knowledge, etc. But there are interesting and noteworthy parallels that Husserl scholars have drawn between Husserl’s views on these issues and those of various metaphysical realists.

To cite an example, Husserl scholars have long found it useful to compare his account of essences with Platonist and sometimes also Aristotelian views of essences (Rosado Haddock, 1987; Tieszen, 2011; Moreland, 1989; Thomasson, 2017; de Warren, 2020). The interpretation of Husserl’s notion of noema and his account of knowledge have advanced in a similar way with frequent comparisons, respectively, to Gottlob Frege’s notion of sense (Sinn) (Mohanty, 1974; McIntyre and Smith, 1975; Drummond, 1985; Føllesdal, 1990; Brown, 1990; Hill & Rosado Haddock, 2000) and foundationalism in analytic epistemology (Føllesdal, 1988; Drummond, 1990; Philipse, 2004; Berghofer, 2018; Hopp, 2008 and 2020). The point is that it is not a deal-breaker for substantive comparison of Husserl’s views with those of other philosophers for the latter to typically take some form of metaphysical realism for granted.

The point can be further extended. It is not as if being a metaphysical anti-realist is sufficient for exiting the natural attitude. Metaphysical anti-realists may be as far from Husserl’s outlook with their views as are metaphysical realists. So, by parity of reasoning, one would have to hold also that Husserl’s views cannot be located in relation to views maintained by many anti-realists, either. Here, too, Husserl’s interpreters have nevertheless found it is salutary to do just that. To illustrate, numerous Husserl scholars have made the case that Husserl embraces a kind of verificationism (e.g., about meaning) (Luebcke, 1999; Stone, 2005; Mulligan, 2017; Hopp, 2020). Verificationism is usually construed as a form of metaphysical anti-realism (Rogerson, 1991; Khlentzos, 2016).

Paradigmatic varieties of verificationism, though, are inimical to the kind of turn Husserl urges in encouraging us to take leave of the natural attitude. Consider Rudolf Carnap’s view. For him, accepting verificationism does not lead to a deeper grasp of the fundamental concepts in play in philosophical discourse like it is supposed to for Husserl. In fact, it does the opposite, barring us in principle from developing substantive philosophical accounts of the nature of, e.g., spacetime particulars, numbers, concepts, etc. For Carnap, any talk of what those sorts of things really are can have only a non-cognitive—perhaps practical or pedagogical—import (Carnap, 1950). Husserl, on the other hand, believes the phenomenological reduction is the necessary precondition for clarifying exactly those kinds of issues (Husserl, 1989; Husserl, 1997a).

By implication, Husserl’s view would be hermeneutically sealed off from engagement with any view that remains beholden to the natural attitude and does not begin as Husserl’s does with the performance of phenomenological reduction. If the unacceptability of that consequence is not compelling, let me extend my point a final step further. It would for essentially the same reason block attempts to read the views of the Husserl of Ideas I and other transcendentally-inflected texts, insofar as they are made from the point of view of transcendental reduction, in light of their similarities to those of the Husserl of the Logical Investigations and other pre-transcendental texts of Husserl’s, texts in which phenomenological reduction is absent and many interpreters find instead a kind of realism (Ingarden, 1975, 4–8; Hopp, 2020, 270–274).Footnote 12 Husserl’s views would thus be hermeneutically isolated not only from those of virtually all other philosophers, but also his own at certain points in his intellectual arc. The only apt comparison would be negative in character.

It may be that the phenomenological reduction ought to be discussed in any treatment of Husserl’s theory of perceptual experience and perceptual error and that Husserl scholars have been failing in this regard. And perhaps recognizing the peculiarities of Husserl’s approach to theorizing about perceptual experience is a necessary corrective to problematic tendencies pervasive in contemporary philosophy of perception, as both Cimino (2021) and Doyon (2022) argue in detail. Either of those points can be acknowledged without going so far as to say that Husserl’s view is in a sui generis class of its own, incomparable to any existing alternative.

5 Conclusion

I have argued here that Husserl’s commitment to phenomenological reduction by itself gives no compelling reason to think that his account of perceptual experience is incommensurate with conjunctive or disjunctive views of perceptual experience. In conclusion, I would like to mention three reasons for thinking it is worth our while to settle how Husserl’s view fits into the contemporary debate about hallucination with an openness to his view being lumped in with those already available, like conjunctivism and disjunctivism.

First, efforts along these lines serve to make Husserl’s view intelligible to contemporary readers. Similarities, even if they are not perfect matches, between Husserl’s view and contemporary views are points of contact and potential bridges for mutually enlightening discussion. Second, as attempts to situate Husserl in the contemporary debate make apparent, there is no widely recognized, satisfactory account of how veridical perceptual experience and hallucination relate to one another in Husserl’s thought. That is, attempts like these have highlighted an aspect of Husserl’s thought that stands in need of clarification. Third, advances in Husserl interpretation on other topics have been facilitated by similar attempts to situate Husserl’s thought in relation not only to the views of other phenomenologists and contemporaries of Husserl’s, but also in relation to the views most prevalent in current debates on the pertinent topics. I believe I have illustrated that amply in § 4 above and I do not see why we should expect anything different in this case.