I'm a strong believer in actually building things rather than just talking. But like everyone else in the field, I've got some informal thoughts on what it's all about. Here's my current set of conclusions. I have written a popular science talk on this.
I don't think we have to be over scrupulous about this. The standard I would set is simply that an AI model should be evolutionarily-plausible. I want to see the path along which it could have evolved incrementally from simpler models by natural selection. For me, symbolic AI currently fails this test. (How do symbols evolve from nothing in the infant mind?) As does supervised learning. (Who is the teacher supplying explicit I/O pairs?) I would like to think that I am working on evolutionarily-plausible methods of action selection.
I also think that a sound model of human-level intelligence has to wait until we have a much better model of the underlying animal. It seems to me that language etc. is something which requires as a substrate an already fully-functioning, mobile, pre-linguistic creature. I don't see how you can be intelligent without being a mobile, tactile animal first (that is, I don't believe in the possibility of disembodied, linguistic-only, Eliza or HAL like intelligence). In lyrical terms, if we ever want to make a H.sapiens, the challenge now is to make a H.erectus.
What I'm not into What I am into design evolution, learning, self-organisation symbolic AI, logic, knowledge representation self-modifying stochastic systems embedded in the world simulation, trickery how nature really works one self, global control Society of mind, Minds should not have a Single Thread of Control intelligence, consciousness, NLP, the Turing Test robotics, sensory-motor behavior, action selection, symbol-grounding quantum physics nonlinear physics, biology conceptual models (analysis) algorithms, things you can build (synthesis) A-humans A-life, A-animals
So while I love Moravec's originality, I'm unconvinced that non-human machines will take over the world. They will run into many of the same boring troubles that we have run into. Read Jared Diamond on evolutionary history to understand how easily cultures fail, and how hard our human success was.
So AI is possible in theory (materialism is true) but pretty much impossible in practice (the planet is full). And even if it were possible in practice, the process would not be fun, and could easily stall before full intelligence was reached because of non-cooperation by the creatures themselves.
And of course this also means: Us going immortal. The mind, the body, and why they die, are scientific problems and some day they will be solved. Not in our lifetimes, not in fifty years or any of the other absurd estimates made by AI promoters. Two hundred years would be a more reasonable estimate. But someday, if civilization continues, someday these problems must fall. Immortality is inevitable, real immortality, not in an imaginary spirit world, but here in the real world. The only world there is.
Still sceptical? Well what alternative future do you imagine then? Do you really think that humans are going to go on being forced to die by nature for the next thousands and thousands of years?
The methods below offer only the slimmest of chances of surviving to see that day, but the alternative is no chance at all. Anyway it's great to see people challenging this huge taboo. Death may be natural, but that doesn't mean we have to accept it. We're in charge now, not stupid uncaring nature.
My family tree pages are really a labour of love for ordinary, mortal, unknown humans, those who will have no biographies written about them, those who died too long ago to be missed. No matter what disasters happened to your life, or how early it ended, these carefully compiled pages show that you too once lived, your heart once beat, you were young and anything could happen. And then the moment passed and you vanished into the night.
Someday, when death is voluntary, there will be a record of the earliest-born person in history to go immortal. The methods above may be hopelessly optimistic, but on the other hand, it is just about credible that that person's birthdate might be as early as the twentieth century.

OK back to work.
All these things have been said before by others anyway.
Just thought I'd let you know which positions I find convincing.
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