Because they aren't machines, we don't understand how they work and it's very much an open question whether we ever will. OpenWorm tried and failed the get the

Because they aren't machines, we don't understand how they work and it's very much an open question whether we ever will. OpenWorm tried and failed the get the fully documented behaviours of the C. Elegans nematode (for which we know the complete connectome and the full lineage of every one of the 959 cells of its body) to emerge from simulations of its 302 neurons. We don't understand how an individual neuron works. We don't even understand what an individual neuron really does and the brain contains 100 billion of them. The hubris involved in looking at biological nervous systems and thinking "how hard can it be? Give me a big data centre and 5 years!" is staggering.