I think in practice we don’t know for sure—that’s part of the problem—but there are various reasons to think why this might be possible with vastly less complexity than the human brain. First, the task is vastly less complex than what the human brain does. The human brain does not handle only conscious rational thought, it does a bunch of other things that mean it still fires at full cylinders even when you’re unconscious. Second, lots of artificial versions of natural organs are vastly less complex than their inspiration. Cameras are vastly less complex than eyes. Plane wings are vastly less complex than bird wings. And yet these things outperform their natural counterparts. To me the essence of the reason for this is that evolution deals in compromises. It can never design just a camera. The camera must be made of organic materials, it must be self organising and self repairing, it must be compatible with everything else and it must be achievable via a set of small mutations that are each as or more viable than the previous one. It’s all stumbling around in the dark until you hit something that works under the many, many constraints of the problem. Meanwhile, artificial intelligent design on our part is a lot more deliberate and a lot less constrained. The AI itself doesn’t need to do anything more than be an AI—we’ll provide the infrastructure, and we’ll throw money at it to keep it viable until it doesn’t need it any more, because we foresee the future and can invest on it. That’s more than evolution can do, and it’s a significant advantage that can compensate for a lot of complexity.
I think in practice we don’t know for sure—that’s part of the problem—but there are various reasons to think why this might be possible with vastly less complexity than the human brain. First, the task is vastly less complex than what the human brain does. The human brain does not handle only conscious rational thought, it does a bunch of other things that mean it still fires at full cylinders even when you’re unconscious. Second, lots of artificial versions of natural organs are vastly less complex than their inspiration. Cameras are vastly less complex than eyes. Plane wings are vastly less complex than bird wings. And yet these things outperform their natural counterparts. To me the essence of the reason for this is that evolution deals in compromises. It can never design just a camera. The camera must be made of organic materials, it must be self organising and self repairing, it must be compatible with everything else and it must be achievable via a set of small mutations that are each as or more viable than the previous one. It’s all stumbling around in the dark until you hit something that works under the many, many constraints of the problem. Meanwhile, artificial intelligent design on our part is a lot more deliberate and a lot less constrained. The AI itself doesn’t need to do anything more than be an AI—we’ll provide the infrastructure, and we’ll throw money at it to keep it viable until it doesn’t need it any more, because we foresee the future and can invest on it. That’s more than evolution can do, and it’s a significant advantage that can compensate for a lot of complexity.