Why is asking 'can machines think?' assuming our thinking could be modeled as a machine? It's raising the possibility that our thinking could be modeled as a machine. Given that, as you acknowledge, we don't have a clue how our mind works, it seems premature to rule out this possibility. Rather, I would say that ruling it out betrays an assumption that we understand how the mind works enough that we can say that it is definitely not replicable by a machine, and that assumption seems unjustified.