The Disunity of Consciousness in Everyday Experience

A substantial philosophical literature explores the "unity of consciousness": If I experience A, B, and C at the same time, A, B, and C will normally in some sense (exactly what sense is disputed) be experientially conjoined. Sipping beer at a concert isn't a matter of experiencing the taste of beer and separately experiencing the sound of music but rather having some combined experience of music-with-beer. You might be sitting next to me, sipping the same beer and hearing the same music. But your beer-tasting experience isn't unified with my music-hearing experience. My beer-tasting and music-tasting occur not just simultaneously but in some important sense together in a unified field of experience.

Today I want to suggest that this picture of human experience might be radically mistaken. Philosophers and psychologists sometimes allow that disunity can occur in rare cases (e.g., split-brain subjects) or non-human animals (e.g., the octopus). I want to suggest, instead, that even in ordinary human experience unity might be the exception and disunity the rule.

Suppose I'm driving absentmindedly along a familiar route and thinking about philosophy. Three types of experience might occur simultaneously (at least on "rich" views of consciousness): visual experience of the road, tactile and proprioceptive experience of my hands on the wheel and the position of my body, and conscious thoughts about a philosophical issue. Functionally, they might connect only weakly: the philosophical thoughts aren't much influenced by the visual scene, and although the visual scene might trigger changes in the position of my hands as I adjust to stay in my lane, that might be a causal relationship between two not-very-integrated sensorimotor processes. (Contrast this with the tight integration of the parts of the visual scene each with the other and the integration of the felt position of my two hands and arms.) Phenomenologically, that is to say experientially, must these experiences be bound together? That's the standard philosophical view, but why should we believe it? What evidence is there for it?

One might say it's just introspectively obvious that these experiences are unified. Well, it's not obvious to me. This non-obviousness might be easier to grasp if we carefully separate concurrent introspection from retrospective memory.

In the targeted moment, I'm not introspecting. I'm absorbed in driving and thinking about philosophy. After I start introspecting, it might seem obvious that yes, of course, I am having a visual experience together with a tactile experience together with some philosophical thoughts. But this introspective act alters the situation. I am no longer driving and thinking in the ordinary unselfreflective way. It seems at least conceptually possible that the act of introspection creates unity where none was before. Our target is not what things are like in (presumably rare) moments of explicit self-reflection, but rather in the ordinary flow of experience. Even if experiences are unified in moments of explicit reflective introspection, we can't straightaway infer that ordinary unreflective experiences are similarly unified. To move from one type of case to the other, some further argument or evidence is necessary.

The refrigerator light error is the error of assuming that some process or property is constantly present just because it's present whenever you check to see if it's present. Consider a four-year-old who thinks that the refrigerator light is always on because it's on whenever she checks it. The act of checking turns it on. Similarly, I suggest: The act of checking to see if your experience is unified might create unification where none was before. It might, for example, create a higher-order representation of yourself as conscious of this together with that; and that higher-order representation might be the very thing that unifies two previously disparate streams. Concurrent introspection cannot reveal whether your experience was unified before the act of introspective checking.

[illustration by Nicolas Demers, p. 218 of The Weirdness of the World]

Granting this, one might suggest that we can check retrospectively, by remembering whether our experiences were unified. However, this is a challenging cognitive task, for two reasons.

First, you can't do this easily at will. Normally, you won't think to engage in such a retrospective assessment unless you're already reflecting on whether your experience is unified. This ruins the test; you're already self-conscious before you think to engage in the retrospection. If you reflect retrospectively on your experience just a moment before, that experience won't be representative of the ordinary unselfconscious flow of experiences. Alternatively, you might reflect on your experiences from several minutes before, when you know you weren't thinking about the matter. But retrospective reflection over such an extended time frame is epistemically dubious: subject to large distortions due to theory-ladenness, background presupposition, and memory loss.

The best approach might be to somehow catch yourself off-guard, with a preformed intention to immediately retrospect on the presence or absence of unity. One might, for example, employ a random beeper. Such beeper methodologies are probably an improvement over more informal attempts at experiential retrospection. But (1.) even such immediately retrospective judgments are likely to be laden with error; and (2.) I've attempted this myself a few times over the past week, and the task feels difficult rather than obvious. It's difficult because...

Second, the judgment is subtle and structural. Subtle, structural judgments about our own experience are exactly the type of judgments about which -- as I've argued extensively -- people often go wrong (and about which, in conscientious moments, many people appropriately feel uncertainty). How detailed is the periphery of your visual imagery, and how richly colored, and how is depth experienced? Many introspectors find the answers non-obvious, and the answers vary widely between people independently of cognitive performance on seemingly-imagery-related tasks. Another example: How exactly do you experience the bodily components of your emotions, if there are bodily components? That is, how exactly is your current feeling of (say) mild annoyance experienced by you right now (e.g., is it partly in the chest)? Most people I've interviewed will confess substantial uncertainty when I press them for details. Although people seem to be pretty good at reporting the coarse-grained contents of their experiences ("I was thinking about Luz", "I was noticing that the room was kind of hot"), regarding structural features such as the amount of detail in our imagery or the bodily components of emotion, we are far from infallible -- indeed we are worse at such introspective tasks than we are at reporting similar mid-level structural features of ordinary objects in the world around us.

To get a sense of how subtle and structural the unity question is, notice what the question is not. The question isn't: Was there visual experience? Was there tactile/proprioceptive experience? Were there conscious thoughts about philosophy? By stipulation, we are assuming that you already know that the answer to all three is yes.

Nor is the question about the contents of those visual, tactile/proprioceptive, and cognitive experiences. Maybe those, too, are readily enough retrospectable.

Nor is the question even whether all three of those experiences feel as though they belong among the immediately past experiences of my currently unified self. Presumably they do. It doesn't follow that at the moment they were occurring, there was a unified experience of vision-with-hands-on-the-wheel-with-philosophical-thoughts. There's a difference between a unified memory now of those (possibly disunified) experiences and a memory now of those experiences having been unified then. Analogously, from the fact that there are three balls together in your hand now it doesn't follow that those balls were together a moment ago. Your memory / your hand might be bringing together what was previously separate.

The question is whether those three experiences were, a moment ago when you were engaged in unselfconscious ordinary action, experienced together as a unity -- whether there wasn't just visual experience and tactile experience and philosophical thought experiences but visual-experience-with-tactile-experience-with-philosophical-thoughts in the same unified sense that you can presumably now hold those three experience-types together in a single, unified field of consciousness. What I'm saying -- and what I'm inviting you to set yourself up (using a beeper or alarm) to discover -- is that the answer is non-obvious. I can imagine myself and others going wrong about the matter, legitimately disagreeing, being perhaps too captured by philosophical theory or culturally contingent presuppositions. None of us should probably wholly trust our retrospective judgments about this.

Is there a structural, cognitive-architecture argument that our experiences are generally unified? Maybe yes. But only under some highly specific theoretical assumptions. For example, if you subscribe to a global workspace theory, according to which cognitive processes are conscious if and only if they are shared to a functional workspace that is accessible to a wide range of downstream cognitive processes and if you hold that this workspace normally unifies whatever is being processed into a single representational whole, then you have a structural argument for the unity of consciousness. Alternatively, you might accept a higher-order theory of consciousness and hold that in ordinary cognition the relevant higher-order representation is generally a single representation with complex conjoined contents (e.g., "visual and tactile and philosophical-thought processes are all going on"). But it's not clear why we should accept such views -- especially the part after the "and" in my characterizations. (For example, David Rosenthal's higher-order account of phenomenal unity is different and more complicated.)

I'm inclined to think, in fact, that the balance of structural considerations tilt against unity. Our various cognitive processes run to a substantial extent independently. They influence each other, but they aren't tightly integrated. Arguably, this is true even for conscious processes, such as thoughts of philosophy and visual experiences of a road. Even on relatively thin or sparse views of consciousness, on which only one or a few modalities can be conscious in a moment, this is probably true; but it seems proportionately more plausible the richer and more abundant conscious experience is. Suppose we have constant tactile experience of our feet in our shoes, constant auditory experience of the background noises in our environment, constant proprioceptive experience of the position of our body, constant experience of our levels of hunger, sleepiness/energy, our emotional experiences, our cognitive experiences and inner speech, etc. -- a dozen or more very different phenomenal types all at once. You adventurously outrun the currently available evidence of cognitive psychology if you suggest that there's also constantly some unifying cognitive process that stitches this multitude together into a cognitive unity. This isn't to deny that modalities sometimes cooperate tightly (e.g., the McGurk effect). But to treat tight integration as the standard condition of all aspects of experience all the time is a much stronger claim. Sensorimotor integration among modalities is common and important, yes. But overall, the human mind is loosely strung together.

Here's another consideration, though I don't know whether the reader will think it renders my conclusion more plausible or less. I've increasingly become convinced that the phenomena of consciousness come in degrees, rather than being sharp-boundaried. If we generalize this spirit of gradualism to questions of phenomenal unity, then it's plausible that there aren't only two options -- that A, B, and C are either entirely discretely experienced or fully unified -- but instead a spectrum of cases of partial unity. Our cognitive processes of course do influence each other, even disparate-seeming ones like my philosophical thoughts and my visual experience of the road (if there's a crisis on the road, for example, philosophy drops from my mind). So perhaps our ordinary condition, before rare unifying introspective and reflective actions, involves degrees of partial, imperfect unity, rather than complete unity or complete disunity. (If you object that this is inconceivable, my reply is that you might be applying an inappropriate standard of "conceivability".)

The arguments above occurred to me only a week ago. (As it happened, I was absent-mindedly driving, thinking about philosophy.) So they haven't had much time to influence my phenomenological self-conception. But I do find myself tentatively feeling like my immediate retrospections support rather than conflict with the ideas expressed here. When I retrospect on immediately past experiences, I recall strands of this and that, not phenomenologically unified into a whole but at best only loosely joined. The introspective moment now strikes me as a matter of gathering together what was previously adjacent but not yet fully connected.

If you know of others who have expressed this idea, I welcome references.

[for helpful conversation, thanks to Sophie Nelson]