[Tuna-Fish]

Broad understanding of how the brain functions it not necessary (and would not be sufficient) to replicate it. To make a model of a brain that runs on a computer, we only need to be able to replicate it's basic building blocks, and then copy the structure of a brain over.

The basic technologies to do this already exist, and are presently used to reverse engineer microchips (among other things). What you do is first freeze a brain, and then carefully slice a few micrometers off the top. Then record all the connections between neurons in the top layer. Slice another layer off and continue.

This would take a very long time, and cost hundreds of billions. It would not, however, require any advancement in technology over our present level. The key technology we presently lack is a computing substrate sufficient to run the simulated brain.

[owyn]

That's one approach, but I don't think there's any evidence that you would end up with a working brain at the end, let alone a copy of the individual you started with. And good luck finding a volunteer. :)

The brain's functionality is not just due to the physical connections between neurons, it's the chemical and electrical connections as well, operating on various simultaneous levels (that is, the frequency of firing as well as the strength of firing of neurons matters). A frozen brain isn't working, and you need to copy all that stuff too, and the technology to do that doesn't exist. We can barely measure it, let alone reproduce it.

I don't think you can say that a thorough understanding of all those multiple levels of complexity in the brain just isn't necessary. I really don't think it is that easy.

[yummyfajitas]

To make a physics analogy, I don't need to understand gas laws to reproduce them by simulating newtonian mechanics.