"This is hugely debatable. Why is AGI inevitable? Even given great amounts of computing resources, a artificial general intelligence does not just automatically appear [...]"
Well no one thinks AGI will appear without anyone working on it, but lots and lots of people are working on it now. And since there are huge incentives to create one, the belief is that more people will work on it as time goes on.
"[...] there really isn't any evidence that I know of that a general intelligence is any closer than it was 20 years ago."
Well, in some sense I agree, in that we still have no idea how far off AGI is. If it's going to happen in 10 years, we should definitely prepare now. If it's 500 years away, maybe it's too early to think about it. But since neither of us knows, wouldn't you say it's worth putting some effort to working towards safety?
In another sense though, I disagree with you that we're not any closer to AGI. As you said jsut the sentence before, fields like comptuer vision have advanced tremendously. While this doesn't necessarily mean AGI is closer, it certainly seems that the fields are related, so advancement in one is a sign that advancement in the other is closer.
Human intelligence evolved through a (very long!) series of natural processes, to the best of my knowledge. To say it was "created" implies something closer to a religious or philosophical opinion, rather than something supported by science.
> 2. At some point, humanity will create an "artificial general intelligence". (Since we'll just keep improving science and technology, and there's no fundamental reason why this won't eventually allow us to create an intelligence.
This is hugely debatable. Why is AGI inevitable? Even given great amounts of computing resources, a artificial general intelligence does not just automatically appear, it must somehow be designed and programmed. Fields like computer vision have grown tremendously using techniques like deep learning, but there really isn't any evidence that I know of that a general intelligence is any closer than it was 20 years ago.