What is the computing power of the brain? Well, it is so vast, no one really has any idea. There are some expensive research programs that are using some of the fastest arrays of supercomputers to model a neuron. But these programs are only modeling the inputs and outputs of a neuron, not the processing that goes on inside a single neuron, which is vast. The human brain has about 80 billion neurons with 100 trillion connections.
Current technology (microscopes and phosphorescence) can record 80,000 neurons firing a second. That is one millionth of the number of neurons in the human brain. Neurons fire at a rate of about once a millisecond so that is one thousand times faster than is currently recordable. So just to record the neurons firing in the human brain, current technology is nine orders of magnitude short. Plus a neuron firing is not a binary operation but a very complex phenomenon that transmits much more than one bit of information. No one really knows how much data is transmitted in a neuron firing. And again this take no consideration of the processing going on inside the neuron. Plus, the tools to analyses the information from recording 80,000 neurons firing a second is still quite basic and has not yielded much of use. I am sure this technology will continue to improve and make useful discoveries but it is so far from modeling the human brain that it is just guess work to know even how many ordered of magnitude it has to go. We do not understand many basic questions about how the brain operates such as how the brain stores information.
The movies like to show us robots that look, think, and act like humans (The Terminator series, Ex-Machina, on and on). It is easier for the movie makers to use humans for robots than to try to build an actual robot. The same goes for time travel. Instead of trying to build a whole new futuristic set, they just have the future travel back to our time and look like us. They just saved millions of dollars in production costs. But these are just stories. You can not go back in time and you can not build a human brain out of silicon chips. It is just never going to happen.
Many reasonable people are quick to assume that the brain is simply a deterministic machine. I am sure many scientists at the dawn of the industrial age thought the brain was some kind of hydrolic or mechanical geared machine like a stream engine, the leading technology at the time. Now people think the brain is some kind of digital information processor. They will tell you that consciousness and free will are illusions. If pressed, they will often resort to ad hominem attacks, which I find ironic. I find no basis for giving up on the idea of free will. Free will is an experience that I have prior to the deterministic world. Extrapolating the relatively paltry processing power of computers to what the brain does seems a particularly ludicrous argument against free will.
