The biggest barrier to understanding consciousness is the fact that we don't know how to recognize it. We assume other people are sentient because they seem analogous to ourselves, but we don't actually knowingly "detect" their sentience. We just assume it's there based on other things that we can detect. But that makes it pretty hard to predict it or say much about it. The problem isn't necessarily that we can't detect consciousness - only that we can't know for sure whether what we detect is conscious or not.

But that said, there's one big thing we can infer, namely, that consciousness is both affected by, and has an effect on, the physical world. We know the first part because consciousness is obviously generated by our physical body. And we know the second part because our body wouldn't have adapted to generate consciousness if consciousness weren't affecting its actions in ways that helped it to survive.

And another thing I think we can say about consciousness is that it's fundamentally willful. It has the capacity to feel good or bad, and always has a more-or-less strong desire or compulsion to feel better, which is the impetus for it having an effect on the physical world.

But we might then notice that consciousness has a lot in common with normal physical forces, like gravity and electromagnetism. Like those forces, it has an effect on matter, and can very in strength.

But where I think we often go wrong is in assuming that consciousness is fundamentally different than, and separate from, those forces. But I can't see any reason why we make that assumption. And by making that assumption (that consciousness is different from other forces), we add complexity to our mental model that need not be there.

So in other words, I think we ought to simply assume that, sentience is fundamentally forceful, and that, where there is force (e.g. gravity or electromagnetism), there, too, is sentience.