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Someday we might meet spacefaring aliens who engage us in (what seems to be) conversation. Some philosophers -- for example Susan Schneider and (if I may generalize his claims about superficially isomorphic robots to superficially isomorphic aliens) Ned Block -- have argued that such aliens might not really have conscious experiences. In contrast, I hold what I believe to be the majority view that aliens who outwardly behaved similarly to us would very likely have conscious experiences. In the phrase that Thomas Nagel made famous, there would be "something it is like" to be an alien.

I offer three arguments in defense of this general conclusion. I stipulate that the aliens I'm considering have arisen through a long evolutionary process, that they are capable of sophisticated cooperative technological behavior, and that they interact with us in ways that it is natural for non-philosophers to interpret as having comprehensible linguistic content.

The Linguistic Argument.

An alien descends from its spaceship. Upon meeting the local population, it raises an appendage and begins touching things. It touches its leg and says "bzzbl". It touches its elbow and says "tikpt". It touches a tree and says "illillin". And so forth. Furthermore, it does so in reliable and repeatable ways, so that this behavior is naturally interpreted as linguistic labeling. When a human touches a tree and says "illillin" the alien says "hi". When a human touches a tree and says "bzzbl", the alien says "pu". The pattern of hi/pu responses is naturally interpreted as affirmation and negation. From this starting point, humans seem to learn the alien language and the alien seems to learn the local human language. Learning proceeds smoothly, except for a few understandable hiccups, so that after several months, the aliens and the local humans are cooperating in complex activities with apparently complex linguistic understanding. For example, the alien emits sounds like this: "After I enjoy eating the oak tree down the road by David's house, I plan to take a half-hour nap at the bottom of Blackberry Pond. Could we meet to talk about Martian volcanology after I've finished my nap?" All proceeds as expected. The alien eats the tree, takes the nap, and afterwards engages in what appears to be a dicussion of Martian volcanology. If this was not approximately how things went, the alien would not be the right kind of outwardly similar entity that I have in mind.

To be outwardly similar -- and also just for good architectural reasons in a risky world -- the alien will also presumably be able to discuss its interior states and perceptual states. When it is running low on nutrition and needs to eat, it will say something like "I'm getting hungry". When it can't visually detect a distant object that a human interlocutor is pointing out, it will say something like, "Sorry, I can't see that. Oh, wait, now I can!" When it fears for the safety of its mate who has just wandered onto the highway, it will say something like, "I'm worried that she might be struck by a car" or "I hope she gets across the road okay!" Now suppose a human interlocutor says something like, "Do you really have conscious experiences? I mean, is there something it's like for you to experience red and to feel pain? Do you have imagination and understanding and emotional feelings?" If the alien is generally similar to us in its linguistic behavior, and if the question is phrased clearly enough, it will say yes. I think this is plausible given the rest of the set up, but we can also stipulate if necessary that if such an alien said no it wouldn't be a superficial isomorph outwardly similar to us in the intended respect.

Although I'm not sure how Schneider and Block would react to this particular case, my interlocutor is someone who thinks it still remains a live possibility that the alien really has no conscious experiences underneath it all, because it has the wrong type of internal structure. (Maybe it's made of silicon inside, or hydraulics, or maybe it engages in fast serial cognitive processing rather than parallel processing.) The thought behind the linguistic argument (which I leave undeveloped for now) is that it would be unnatural, awkward, inelegant, and scientifically dubious to interpret the alien's speech as failing to refer both to trees and to genuine conscious mental states that it possesses.

The Grounds of Consciousness Argument.

What theoretical reasons do we have for thinking that creatures other than us have conscious experiences? I'm inclined to think we rely on two main grounds: (a.) sophisticated outward behavior similar to outward behavior that we associate with consciousness in our own case, and (b.) structural similarity between the target creature and us, with respect to the types of structures we associate with consciousness in our own case. By stipulation, (a) favors the alien. So the question is whether divergence in (b) alone would be good enough grounds to seriously doubt the existence of conscious experience despite seemingly-introspective reports about consciousness.

If the structural situation is bad enough, that can ground plausible denial. A remote-controlled puppet with a speaker in its mouth might exhibit sophisticated outward behavior, but we would not want to attribute consciousness to the puppet. (We might want to attribute consciousness to the puppet-manipulator system or at least to the manipulator.) Similarly, we might reasonably doubt the consciousness of an entity programmed specifically to act as though it is conscious, even if that entity passes the Turing test or similar, because there is possibly something suspicious about having such a programming history: Maybe the best explanation of the entity's seeming-consciousness is not that it is conscious but only that it has been programmed to act as though it is. (I'm not saying I agree with that position, only that it is a reasonable position.)

To avoid these doubts about the structural story, I have stipulated that the aliens have a long evolutionary history. The question then becomes whether a naturally-evolved cognitive structure underlying such sophisticated and apparently linguistic behavior might not be sufficient for consciousness, if it is different enough from our own -- such as maybe a fast serial cognitive process rather than the massively parallel (but slowish) structure of neurons, or relying on a material substrate different than carbon. My intended sense of "might" here is not the thin metaphysical sense of "might" in which we might allow for philosophical zombies, but rather scientific plausibility.

A good approach to this question, I think, is to consider what it is about neurons aligned in massively parallel structures that explains why such neurons give rise to consciousness in our case. There must be something functionally awesome about neurons; it's not likely to be mysterious carbon-magic, independent of what neurons can do for us cognitively. So what could be that functionally awesome thing? The most plausible answers are the kinds of answers we see in broadly functionalist approaches to consciousness -- things like the ability to integrate information so as to respond in various sophisticated ways to the environment, including retaining information over time, monitoring one's own cognitive condition, complex long-term strategic planning, being capable of creative solutions to novel predicaments, etc. If serial processing or silicon processing can do all of the right kind of cognitive work, it's hard for me to see good theoretical reason to think that something necessary may be missing due merely to, say, the different number of protons in silicon or the implementational details of transfer relations between different cognitive subprocesses. It's a possible skepticism, but it's a skepticism without warranted grounds for doubt.

The Copernican Cosmological Argument.

According to the Copernican Principle in scientific cosmology, we are unlikely to be in a privileged position in the universe, such as its exact center. It's more reasonable, according to the principle, to think that we are in mediocre, mid-rent location among all of the locations that possibly support observers capable of reflection about cosmological principles. (However, the Anthropic Principle allows that we shouldn't be surprised to be in a location that supports cosmological observers, even if such locations are uncommon. For purposes of this post I am assuming that being an "observer" requires cognitive sophistication but does not require phenomenal consciousness if the two are separable. We can argue about that in the comments, if you like!)

The Copernican Principle can, I think, plausibly be applied to consciousness as follows. Stipulate, as seems plausible, that complex coordinated functional responsiveness to one's environment, comparable to the sophistication of human responsiveness, can evolve in myriad different ways that diverge in their internal structural basis (e.g., carbon vs non-carbon, or if carbon is essential because of its lovely capacity to form long organic molecules, highly divergent carbon-based systems). If only one or a few of these myriad ways gave rise to actual conscious experience, then we would be especially lucky to be among the minority of complex evolved seemingly-linguistic entities who are privileged with genuine conscious experience. There would be systems all across the universe who equally build cities, travel into space, write novels about their interactions with each other, and monitor and report their internal states in ways approximately as sophisticated as ours -- and among them, only a fraction would happen to possess conscious experience, while the other unfortunates are merely blank inside.

It is much more plausible, on Copernican grounds, to think that we are not in this way especially privileged entities, lucky to be among the minority of evolved intelligences who happen also to have conscious experiences.

Eric Schwitzgebel

http://schwitzsplinters.blogspot.com/2018/12/three-arguments-for-alien-consciousness.html