Much of the current hope of reconstructing a functioning brain rests on connectomics: the ambition to construct a complete wiring diagram, or “connectome,” of all the synaptic connections between neurons in the mammalian brain. Unfortunately connectomics, while an important part of basic research, falls far short of the goal of reconstructing a mind, in two ways. First, we are far from constructing a connectome. The current best achievement was determining the connections in a tiny piece of brain tissue containing 1,700 synapses; the human brain has more than a hundred billion times that number of synapses. While progress is swift, no one has any realistic estimate of how long it will take to arrive at brain-size connectomes. (My wild guess: centuries.)
Miller goes on to explain all of the additional difficulties future scientists would encounter in this endeavor due to the enormous complexities of our brain’s anatomy. His argument is fascinating even if you aren’t hoping to live for eternity on Google Drive; I had no idea just how complex the components of our brain such as neurons and synapses are. Each synapse is a world in itself.
Kurzweil’s rebuttal would be that although all of these tasks appear intractable now, the exponential growth of scientific knowledge will reduce the difficulty of each problem Miller identifies far faster than the pace of current scientific progress suggests. One of Kurzweil’s favorite examples is the Human Genome Project, which took 7 years to sequence the first 1% of the humane genome and just another 7 years to sequence the last 99%. I suspect, however, that even exponential growth might not save Kurzweil in this case. After all, not all rates of exponential growth are equal and it’s not like we have full-brain “sequencing” machines just yet.
Adding complexity to our models does not necessarily give us a more realistic picture of brain circuits because we do not know enough about the details of this complexity to model it accurately, and the complexity can obscure the relationships we are trying to grasp.
That adding more detail to a model does not always increase model performance is an effect that has been well-studied in the domain of climate science. Are there philosophers studying brain modelling as well?
Source and Image: Will You Ever Be Able to Upload Your Brain? – The New York Times