Why Do We Have Consciousness?

"Why do we feel?" is a philosophical puzzle often addressed by zombie talk.

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When philosophers talk about consciousness, zombies often come up. A philosophical zombie, unlike a horror movie zombie, does not shuffle around looking for brains to eat. A philosophical zombie, in fact, looks and acts just like an ordinary person. The difference is that a philosophical zombie does not have an internal conscious experience.

A non-zombie might feel hunger, anticipation, maybe some concern or excitement while fixing themselves breakfast. A zombie makes the same breakfast but feels nothing.

According to philosopher David Chalmers, we can imagine a being with no internal conscious experience having the same types of cognitive processes we conscious folks do*. That raises a question: Why does it feel like something to go about our days, cognitively processing? Why aren’t we philosophical zombies, just getting on with our daily tasks without feeling any pesky feelings inside?

I’m writing this post because I just finished an excellent book, The Hidden Spring by neuroscientist and psychoanalyst Mark Solms, which presents another response to this philosophical puzzle. In the book, Solms argues that there are some higher-level information processing functions, like turning input into the eye into recognition of visual forms, that can be easily imagined to happen unconsciously. (AI models released in recent years have shown that with the correct information processing setup, a computer can extract visual forms from the raw input of an image.) There is, however, one function of the brain that we cannot imagine being anything but conscious: feeling.

More specifically, Solms argues that affect, that core element of mood and emotional experiences, is necessarily conscious. No philosophical zombie could have affect (or mood or emotion), because that is a process that is necessarily conscious. It always “feels like something” to be in a mood. Moreover, Solms and several other prominent neuroscience researchers are coming to the consensus that affect is the core of consciousness. The core of what is needed for conscious experience—in people and animals—is affect.

Affect in this model—and in decades of psychology research—is thought of as conveying information about internal states. It comes from a mismatch between your current needs—for hunger, for rest, for shelter, for social connection—and your current state. Negative feelings come from “not enough” and positive feelings come from satisfied needs. We have them because they help summarize what our body is processing about our internal state. Feelings help guide us toward actions that avoid threats and take advantage of opportunities.

We can all recognize the motivating power of feelings in our daily lives. If we feel like we are on the right track in some task, we get excited and want to continue our activities. If we feel like we’re in a threatening situation, we get scared or angry and want to take action to get out of or change that situation. We need feelings, according to Solms, because they help us decide which actions to take next. A positive feeling is the body’s shorthand way of communicating a “best guess” that an action will be beneficial, while a negative feeling is shorthand for “don’t do that!”

How much information you can hold in your conscious mind is, famously, limited. Research on working memory finds that we generally can only hold around five pieces of information in our mind at one time. The way around this limit is generally a process called “chunking.” If we can remember only five pieces of information, then one way to get more into memory is to remember complex patterns as a single piece of information. Think of the way a phone number is broken into three- or four-digit “chunks” when you write it down: the area code, the first three digits, and then the next four digits. It’s easier to remember when the information is summarized in chunks.

Feelings account for information about bodily processes.

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We can think of affect, then, as a sort of “chunk” of information about predicted future states. Positive feelings are a summary that’s easy to keep in mind. If we’re choosing between multiple options, we could just compare the feelings they elicit to get a sense of what our body and unconscious mind have predicted will result from each option. (And, just as the “chunk” of an area code can be further examined in terms of its three digits, we can also imagine further examining a summary feeling to understand its parts. Processing feelings like this is at the heart of psychotherapy.)

Neuroscience research backs up Solms’ claim. First, there is the pioneering work described by Antonio Damasio in Descartes’ Error. In that book, Damasio describes patients with brain damage that severely limits their ability to experience emotional reactions. As a result, they are able to do detailed “higher level” logical calculations but unable to simply commit to a decision. He describes patients who can tell you everything about the pros and cons of which restaurant to go to lunch at (how long it takes to get there, how pricey the food is, how long it’s been since they’ve eaten there) but can’t turn those details into a single summary judgment of which restaurant to go to. No affect, no summary signal allowing for decision-making.

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There is also evidence, reviewed in detail in Solms' book, that consciousness comes from deep brainstem areas. In particular, Solms identifies the reticular activating system as the seat of consciousness. This is, crucially, not the prefrontal cortex, where decades of research shows we do most of our complex processing and decision-making. Instead, the reticular activating system summarizes information coming into the body about sleep, pain, heart rate, and other basic biological functions. It is a basic structure seen in many animal species. Consciousness comes from the part of the brain that keeps track of “how you’re doing” at a fundamental level: Are you breathing right, is your heart beating right, is anything hurting, etc.?

So why do we have conscious experiences? In Solms’ model, it’s because conscious experiences are what allow animals to anticipate the consequences of their actions at a basic level. As Solms puts it on page 295: Consciousness “is fundamentally affective.” The core of consciousness is the body and mind’s summary judgment of what will and won’t be helpful. It’s also the one thing we can’t even imagine being part of a philosophical zombie: feeling.

* One response to the idea of philosophical zombies is to say that just because we can imagine them, doesn’t mean they are actually possible in real life. In fact, it may be that to do something as complex as living a full day in a human life, you need consciousness. We just have a false intuition that you don’t. I’m sympathetic to that argument, but I find the argument presented here even more compelling. Both likely help address the philosophical puzzle put out by Chalmers.