What is it like to be a bat? A bat’s brain includes a complex auditory cortex to support its echo-based navigation system; scientists claim to understand those brain mechanics quite well. But how does it actually feel to live in that world of high-pitched sounds that form themselves into objects? We don’t know. No matter how complete our technical knowledge of the creature’s brain, its “mind” or “consciousness” will always remain something extra beyond our understanding.

The philosopher Thomas Nagel uses the bat example to illustrate the brain/mind distinction in relation to humans: no matter how far we go towards understanding the human brain in a “mechanistic” sense, we will never fully comprehend that extra component of mind or consciousness. In fact, many scientists and philosophers say, we do not even really know what consciousness is and maybe we never really will. According to the purely mechanistic approach, on the other hand, if we could understand scientifically everything about the brain, then we would also understand mind or consciousness: anything we don’t yet know about those things is only a result of our incomplete scientific understanding of the brain.

For years now in Switzerland a project has been underway to produce a complete detailed plan of the human brain and ultimately to reproduce its effects. The Blue Brain Project (BBP) is a joint undertaking, begun in 2005, between IBM and the École Polytechnique in Lausanne. Using IBM’s Blue Gene supercomputer, BBP initially produced at the end of 2006 a “model” of a human neocortical column (the basic unit of the major part of the brain, loosely similar to the micro-chip). That model is serving as the basis for BBP’s work on producing a complete simulation of the human brain.

IBM has previously been involved in various types of artificial intelligence (AI) projects. In 1997, an IBM-developed computer, Deep Blue, defeated world chess champion Gary Kasparov in a match (the “Blue” in the name of many IBM projects refers to the company’s official colour). Kasparov claimed that some human-like aspects of Deep Blue’s play were actually due to intervention by the computer’s programmers rather than the computer itself, but the 1997 match nevertheless gave an important stimulus to computer chess development and AI research in general.

The promoters of BBP insist that the project is directed at helping research on the brain, particularly in relation to psychiatric disorders such as autism, and not at developing AI or the creation of a particular kind of intelligence. However, they state that the tools developed by the project may give a better understanding of the nature of intelligence and consciousness.

But even BBP itself admits that full replication of the effects of the human brain is impossible with current technology. Such replication would require simulation of human brain activity at the molecular level in order to reproduce the activity of neurons. Even the most sophisticated computers available today like Blue Gene are far from powerful enough to achieve this. Some theorists speculate that the computing power necessary for projects like human brain simulation will be available within 40 years.

Once simulation were achieved, various possibilities already examined in science fiction would open up. Perhaps the most significant would be “mind uploading” – the transfer of a complete human mind to a computer or to another body. The idea of mind uploading is not only very mechanistic but is also based on the philosophy of artificial intelligence known as “strong AI”: machine intelligence is not only possible, but from the outside would appear identical to human intelligence.

The concept of mind uploading raises many ethical issues. Would the copied mind be the same “person” as the original? Does a “person” existing only inside a computer have the same human rights as a biological person? If a mind is copied and therefore exists initially in two or more places at once, will each mind’s different future experiences make it become a different person, or is it the same person experiencing different things simultaneously?

Mind uploading also creates a new path towards one of humanity’s oldest dreams: immortality. This approach to immortality is even more radical than that based on the rejuvenation or replacement of body parts to extend human life. If mind uploading became possible, a human mind could theoretically be transferred from one mechanical or biological body to another for as long as an electronic copy of that mind could be preserved.

This kind of immortality would represent for the first time in human history a complete break with Christianity and other religions that are based on an indissoluble connection between the soul (or “mind” in more modern terms) and its body. According to Christian belief, after physical death the body and soul are temporarily separated, but will be reunited upon resurrection. The resurrection body will be somehow transformed, but still recognisable.

The pursuit of immortality through mind uploading would be an attempt to leave the dead physical body behind and to launch the mind alone through eternity. This application of the mechanistic view of humanity – often held by atheists – resembles various early Christian heresies, which readily accepted the immortality and great value of the soul, but refused to give any similar sort of dignity to the body. Some of those heretics, although having no doubt about Christ’s divinity, claimed that the body in which He appeared on earth was just an illusion.

A lack of dignity given to the human body is just one of many concerns expressed about mind uploading and similar projects. Other concerns are similar to those relating to life-extension programmes based on rejuvenation of the body. Although the preservation of the minds of scientists and other important people might be seen as beneficial, it is feared that totalitarian regimes or other groups could use the technology to maintain their power and status indefinitely. Also, there is concern that the expected extreme cost of any such technology would make it available only to the very rich and would therefore help to perpetuate inequalities in society.

However, concerns such as these are unlikely to stop any projects that build upon the advances of BBP in the direction of brain simulation, mind uploading or similar ideas. Research into all these areas offers synergies with many other fields, including computer science and neurology. Financing and support will likely come from a wider group of powerful interests as more people start to believe in the possible applications of the technology. For military and scientific purposes, human brain power enhanced by computers could be a powerful tool for problem solving and invention. Robots equipped with simulated human brains could become important for space exploration.

And all this might be done by replicating the effects of the human mind and consciousness without our even knowing or caring what those things are. Probably a bat does not understand how its mind works, but at least it finds its way in the dark. Let’s hope we manage to do the same.