The complexity and detail in our universe create an incredibly vast search space, which may hinder development rather than promote it. To speed it up we need to be able to narrow the search space by cutting some stuff out and simplifying the model. Do we need to model atoms? Molecules? Organelles? DNA? Some other made up building block?
I have been intrigued by artificial life because I think it takes a more holistic look at that question than AI. I feel like starting with the neuron is kind of a huge assumption, how have we ruled out or accounted for the importance of all the more basic building blocks and developmental milestones of life?
I also think the environment is critical. We formed and evolved as a product of our environment, we have to find food in it; our goals, behaviors and fitness level are largely dependent on/derived from it. An AI doesn't have an environment. It doesn't have any sense of living and being in a place. It can't care about anything. It's not going to see an apple fall and wonder why that happens. It's not alive or doing anything when it's not called to process an input into an output. It makes things up by stitching together words that it has no actual context or experienced meaning for. I find it hard to believe that we're going to achieve anything resembling the interesting characteristics of humans with these abstract Chinese Rooms.