Should we only believe in what is verifiable? If so, we should be skeptical of claims that anything lacks consciousness.

I should be clear about what I mean by consciousness, since people tend to talk past one another on this topic. I am not talking about reasoning, self-modeling, or any particular kind of mental activity or mental content, but rather just bare experientiality. If there is any sort of subjectivity, any experience at all, there is consciousness. This does not require self-awareness or a constructed self-model.

Most consider general anesthesia a clear case of unconsciousness. But maybe instead of making us incapable of experiencing pain, it just paralyzes us and prevents the retention of any memory of the experience. Failure to remember or report an experience is certainly not evidence of a lack of experience. How would we know if this is the case? Is there any way to tell?

Consider split-brain patients. The severing of the corpus callosum seems to split the mind into two distinct parts. Each hemisphere fails to report what is exclusively observed by the other. The ability to integrate information between hemispheres is lost. Unlike the left hemisphere, the right hemisphere can't speak. So if you talk to the patient and get a verbal answer, you generally only hear from the left hemisphere. But there are other ways of asking the right hemisphere questions and getting answers, such as by having it point to objects with the left hand.

...when an object is shown in the right visual field, the visual information travels to the left hemisphere and the patient is effortlessly able to name it. When shown to the left visual field, however, the information travels to the right hemisphere, and when asked, the patient will typically answer that no object was seen. This phenomenon is easily explained by the fact that most people’s speech centre is located in their left hemisphere. When the hemispheres are separated, the left will be capable of naming an object, while the right hemisphere stays mute. Moreover, the left hemisphere will also eagerly answer the question intended for the right hemisphere. When it hears the question directed to the right hemisphere asking what the object was, the left hemisphere correctly and honestly reports that it did not see anything at all.

Now picture yourself listening to the completely normal looking person sitting in front of you saying that he did not see the object. He sounds absolutely sure about this. One might jump to the conclusion that the right hemisphere did not perceive the stimulus. Yet this interpretation drastically changes when the right hemisphere is asked to communicate non-verbally. For example, when instructed to point out the object from a group of objects with the left hand, patients reliably identify the object that had been presented to the right hemisphere. Not just better than chance. Every time. — Lukas J. Volz, Michael S. Gazzaniga

It could be that there are regions of the nervous system that have experiences that never get reported because they aren't connected to language processing and motor areas in the right way. Suppose, for example, that there is something like a separate brain in your liver, and that there is some subjective experience associated with this, perhaps of a sort very different from what we are familiar with. This liver-brain may not be connected to the left hemisphere in the skull in such a way that the left hemisphere is aware of what is happening there. This experience never gets reported and so remains unknown to science.

There might actually be many functions in our nervous system that involve experiences that never get reported because those areas are not highly integrated with areas that can express themselves through behavior. We aren't conscious of regulating our heart rate and generally lack voluntary control of it. But some part of the nervous system controls it. That part may simply not be well-connected to the executive regions. The failure to report such experiences is not evidence that no consciousness of this exists anywhere.

Imagine a room, buried deep underground, with a person inside who has no way of communicating with the outside world. We never hear reports of their experience and we never see behavior. We can stand on the ground and ask toward that room underground if there are any experiences there. Should we interpret the silence as evidence for lack of any experience in that room?

Even in deep sleep, anaesthesia, and so on, it may not be that experientiality switches off entirely. Rather, it could be that the brain simply begins operating in a manner that is less integrated, dissociating into many smaller regions. Or maybe it switches to a very different mode of integrated functioning. Information about what happens during this time might not be available to the waking brain, or might not have a form that would be intelligible to the waking brain. In such a state, a story like those we normally tell ourselves might not be constructed and so none may be available to report. Even with normal dreaming, remembering is often difficult, if not impossible. So people often say, incorrectly, that they didn't have any dreams that night.

When we (the waking brain with ability to report through speech) try to remember what happened during "dreamless" sleep, we come up empty. So we assume that there is no experience whatsoever. We might be making a mistake. Our coming up empty is experienced as finding nothing. We think this means there is nothing there, as if we are directly knowing the nothingness of that unconscious state. But notice that if you mentally try to remember the experiences of another human, you similarly find nothing. Is this evidence that other people lack consciousness? Of course not! All we have here is a failure to access memories of an experience. It is a failure of integration, not a lack of experience.

Usually, when we can't directly access experiences, such as those of other people, we make a judgment about whether they have experiences or not by observing their behavior and making an inference. If they behave like we do during times in our lives that we can remember being conscious, we assume that they too are conscious. Some of this attribution of mind to others like us might also be part of our social instincts.

With animals, we tend to think it more likely that they have experiences when they behave in a way most similar to how we behave during times when we remember being conscious. If they scream when injured, we tend to think they must experience pain. Even a simple retraction from a damaging stimulus is often suggestive to us. But notice that our gradient of consciousness-attribution tracks fairly tightly with similarity to ourselves. This seems a bit suspicious! The more mammal-like the behavior, the more consciousness there must be. Anyone see a problem here?

My dad loved to go fishing. Even as he would use a pair of pliers to pull a hook out of the throat of a fish, even as that fish would struggle in his hands with all its might, attempting to get away, he would tell me with confidence that none of this hurts the fish. As a kid, I believed him. But how could he know this? It seems to me that if the fish would have screamed or cried, he would have thought differently. He never hunted rabbits again after being shocked upon hearing a rabbit scream when struck with an arrow. But of course fish can't scream! They evolved for a very different environment and lack lungs and vocal cords! Is their lack of report of pain evidence that there is no pain? Hardly!

Notice the pattern here. We only attribute consciousness where we have access to reports of experience that have a form we recognize, a form that is very similar to mammal behavior. If there are no reports of experiences, there must be none! This is obviously problematic.

Notice that in the past, this attribution of consciousness tended to be even more restricted to those who looked and behaved exactly like the person making the attribution. Humans doubted experience in animals altogether. White men denied souls, which they thought responsible for consciousness, to animals, and in some cases even to other human races and to women, even despite the fact that these report their experiences.



If we are to be scientific, we should be careful about believing in claims that cannot be verified. Nobody has ever verified the reality of unconsciousness of any kind in any sort of entity ever. We have no evidence whatsoever that such a condition is possible. Where we find no recognizable report of experience, that's all we have, simply a lack of a report, not evidence of unconsciousness.

What does evidence of consciousness look like? It always amounts for us to human-like behavior, and is often only seen as definitive when it involves verbal reports. This is obviously flawed. For one thing, we can create robots that move like humans and speak, making noises that sound like a person claiming they are conscious. Is this evidence? There are also situations like locked-in syndrome where even waking human experiences cannot be reported verbally.

It could be that mycelial networks are conscious. How would we know?

You probably see where this is going. We have no solid reason to believe that there is anything happening in nature at all with no consciousness associated with it. People who consider themselves to be scientific and to only believe based on evidence commonly believe in non-conscious, dead matter, saying that consciousness is "produced by the brain" under very special circumstances. Are they justified in their belief in non-conscious matter? Is this scientific? Should we believe in entities that have never been observed and cannot, even in principle, be observed by us? Is the existence of non-conscious matter falsifiable?

I am not suggesting that a rock might be conscious of being a rock, that rocks have thoughts, animal-like senses or any such thing. Rocks surely lack the right kind of integration for anything like that. But there could be very simple, poorly integrated experientiality in the matter that makes up rocks. This same matter, when arranged in the right way, might even become capable of reporting experience.

It might be that rather than producing consciousness, brains simply amount to a kind of organization that makes recognizable reports of experience possible.

Thoughts?