Is it possible for you to get into my mind?
Can you see into my consciousness enough to verify that I’m conscious like you?
Or are you simply using your idea of your own consciousness to predict my movements? I mean, you haven’t even seen me in real life, so for all that you know I’m just a computer program. But actually there’s a reason why you think that I’m more than just a computer program: In real life, the only things that you’ve ever seen capable of communicating like this with you are other humans; so, when that changes (for example when you see a program that really does act like you or me), you won’t be able to directly know whether you’re talking to a human or a program. Wait, no, on second thought, you won’t ever be able to know: For example, imagine this: You’re responding to a program on a computer and it seems like it has the intelligence and capabilities of a person. How could you tell the difference between it really being a computer program (whatever that means), or it simply being a computer secretly connected to an input device somewhere else, with somebody writing the responses? Well, if the “program” acted exactly like another person (as far as the writing), we wouldn’t have any way of distinguishing between those two scenarios.
But what does that have anything to do with this question? Well, just like you can’t “see into the consciousness” of anybody else, you also can’t see into the consciousness of non-human animals. So why do we consider other people as conscious? If we can’t verify that they’re “actually” conscious (whatever that means), then why the hell do we act as if they are? Well, it’s simply because it works to do that: If I model your movement as being caused by the same things that I know cause my movement, then I’m able to predict what you’re going to do next (in terms of the movement of your body, or actually in terms of the words that appear on my screen) better that I would be able to without that model. In other words, the fact that I think that you’re conscious isn’t anything but a model. I can’t say anything but that it works to consider you (and everybody else on this forum and so on) as acting beings. It’s a good model to predict a certain kind of sensation that I experience: certain objects in outside world (which is also a model!), such as those of language (the sequences of sounds making up spoken words, the sequences of 2D images making up written words, the sequences of 2D images making up other people’s gestures, and so on), those of other people (the 2D images making up other people’s bodies), and so forth. And, in case the point got lost in the length and all of the parenthetical statements, let me re-state the point of this paragraph: I can’t see into the consciousness of anybody else; all that I can do is find that the best model for predicting a certain subset of the perceptions or sensations that I experience is to consider them as conscious. And I get the idea of their consciousness from my consciousness.
So, with that said, we can’t draw a dichotomy between other human’s consciousness and other animal’s consciousness; all that we can say is whether the model works or not. And (as you mentioned in your post, where you talked about how it seems as if your pets have a sense of property rights) it’s pretty obvious that our model of our own consciousness not only works pretty well for understanding how other people behave, but it also works pretty well (but maybe not as well) for predicting how animals behave. Indeed, as Mises said in Human Action, without our understanding of the category of action, we’d be at a loss to understand the behavior of animals. In other words, saying that it “appears that they have concepts of property” is enough to say that they do have concepts of property. I mean, you don’t have any other reason for assuming that I have the concept of property than that it appears as if I do. You can’t say anything about anybody else (whether it’s an animal or another human) except that they appear as if they’re conscious. And what’s that mean anyway? What’s it mean to appear as if you’re conscious? Simple, it means that considering you as conscious is the best model (or simply a good model) for predicting some of what words I’m going to see (or not see) on my screen in the future.