It’s a complicated and slippery concept. It’s useful to start, maybe, in thinking about what may be an easier concept, what is life? You might think that was an easy thing to define. Here on Earth, you can pretty much tell whether something is alive or not. You dig down, you look in a microscope, you figure out does it have RNA, does it have cell membrane? Does it have all those kinds of things that are characteristic of life as we know it on Earth? The question is, what abstractly is something like life? And, we just don’t really know. I remember when I was a kid, there were these spacecrafts sent to Mars, and they would dig up soil, and they had this definitive test for life at some point which was, you feed it sugar and you see whether it metabolizes it. I doubt that in an abstract sense that’s a good, fundamental definition of life. In the case of life on Earth, we kind of have a definition because it’s connected by this, sort of, thread of history. All life is, kind of, connected by a thread of history. It’s sort of the same thing with intelligence. If you ask, what is the fundamental essence of intelligence? Well, in the case of the intelligence that we know with humans and so on, it’s all connected by a thread of history. If we ask, what is intelligence abstractly? That’s a much harder question, and it’s one I’ve thought about for a long time. What’s necessary to say that something is intelligent is for it to be capable of some level of sophisticated computation. If all the thing does is to, kind of, add two numbers together, and that’s the only thing it can do, we’re not going to likely consider it intelligent.