"Love your neighbor as yourself." What? How? I do not mean "what actions does that imply that I should do?" but "how is it even possible to love another as myself?" I know myself, or, at least, I feel like it. I have first-hand experience of things, and those experiences of my feeling such-and-such a way, of experiencing things in certain ways, those things are what I mean when I say that I am conscious. For simplicity's sake, allow the assumption that I love myself as a conscious being, when I love myself. Well then! How am I to love another as a conscious being? How can I even be aware that they are conscious? Am I going to experience what they experience? That would make no difference anyway, it would still just be my experience--my being conscious. If I experience their consciousness, that is just me experiencing consciousness, perhaps differently. What would it even mean to experience their being conscious--to experience their experiencing something?
The problem of other minds is a problem for Christians. If we cannot solve it, then this command is absurd, as is "Love God." If I cannot solve the problem of other minds, then what do I even mean by "God"? If I cannot show how it is that I am justified in believing that other humans have their own minds, how can I possibly show that I am justified in believing in such a mind that is so different than I am?
What is a mind? What do I love when I love myself as a conscious being? Even if I knew, what kind of evidence could I possibly bring to bear on the question whether other humans also have consciousness?
I am a valuing being, with values about those values (metavalues), and, perhaps, a way of thinking about things and values (one might add beliefs in here as well, but I actually think all one needs are the values with their metavalues). I do not come at the world with a fixed point of view, nor with an objective point of view. I value. Suppose all this constitutes a mind. Suppose that my consciousness consists in my metavalues, and values about the way I think about things and values. Very well, but what can I know about the existence (or not) of other minds? How do I know that you value? Is it merely self-reporting? You could be lying, although I might not want to use that word if you are not conscious. What then? Is the command "love your neighbor as yourself" absurd?
I present this as a problem greater than the problem of evil, and applicable to more worldviews. Shall we say that belief in other minds is a "properly basic belief"? Bravo! Why not call anything I can't prove one way or another a "properly basic belief"? My chair is conscious! What? Can you show me that such a belief is unjustified without showing how my belief that you are conscious is also unjustified? Shall we preach to furniture now, too? Ah, but they don't have ears. Our computers, then--the microphones should work well enough.
I could say that they act like me, and I have a mind, so they probably do. It is an argument from analogy, but really, how much like you do other people act? And if this is how you solve the problem, then you really ought to regard anything that acts like you to a similar extent as other people as having a mind (thus, if some robot were to pass the Turing test, you would have to consider it as having a mind). And what about people who don't act much at all like you? Really, is this not simply "they look like me, they act like me, so I like them"? What a selfish, easily prejudiced way of determining whether someone has a mind--if they are enough like me, I'll say they have a mind, if they are not much like me, I'll say they don't have a mind, and then, well, they aren't really people, so I don't have to love them. Monstrous! Or is there some way of showing that there is some particular thing to look for? Well, then, that isn't the same argument anymore, but good luck.
To love another as a valuer, and as a metavaluer, I must value, not necessarily their values per se, but that they value, or, perhaps more correctly, them as one who values. Well then, how do I know that anyone besides me values at all? And if I say that it is because of how they act, well: rocks fall, does that mean that they value obeying the law of gravity? Again: what allows us to distinguish between people, on the one hand, and computers with microphones, on the other, when we preach? There must be something, right? What? Metavalue? But computers could be said to have metavalues: a value implies some "act like this" a metavalue implies some "value like this" well, why do computers act like they do? That can be translated into a metavalue, whatever it is.
Certainly, love, or care about, the other person's facts. That is simple and easy to understand. What it is to love the person themselves, as a person: that is the trouble. Sure, I want them to act in a way that is more consistent with what they say they want. Do I want their good? I want their facts to fit each other and the world, but is that because inconsistency irritates me, or because I love them? It is simply that I want what you do and say to fit how I think the world is, given how I look at the world. I want you to fit into my world, but is that love? It may look the same. Am I doing it because I want to have a consistent world, or because I want you to have a consistent world? But the problem: for the second to be the case, I have to believe that you actually have a world such that its consistency is even able to be improved or doubted.