Immortal Curiosity

11 /26/2005
Notes and thoughts from Stephen Hawking’s The Universe in a Nutshell, chapter 6, Star Trek or Not.

The world’s population plotted through time is a measure of our technological ability to preserve life. During recorded history, this measure has only increased. Of course, there are certain exceptions: the Black death etc. within the last 200 years, population growth has become exponential. Currently, the world population doubles every 40 years. Other measures of technological growth include power consumption and the number of scientific articles published. All three of these measures cannot continue to grow at the same rate that they are now. So what are the possibilities?

Putting self-destruction aside, one major consideration in considering how future development will be shaped would be whether faster than light travel is possible. Since we do not yet possess a complete theory of physics, we cannot rule such a possibility out. However, we do know laws of physics which apply to almost all “normal” situations.

Our own bodies are the most complex systems currently in human possession. However, following biological evolution, the human genome basically follows a random path through genetic possibilities. The complexity of the human genome, i.e. the number of bits encoded, is roughly equivalent to the number of nucleic acids present in the molecule of DNA. The increase in the complexity of life over the first 2 billion years of its existence, was on average one bit per century. Over the last few million years, this rate has increased to about one bit per year. However, this rate was greatly changed when human writing was invented. To get a sense of this, consider that an encyclopedia could contain the same information as the entire human genome. And it is not only the amount of increase in information which became a factor when writing was invented. With writing, such information can be readily updated once it is created, i.e. not only can new information be purposely created, but they can be change purposely in useful ways. The human genome is increasing in the information it contains by about one bit per year. But the information contained by human writing is increasing by about a million bits per second. Even if only one bit per million of this increase is useful, that still leaves the medium of writing 100,000 times more effective than human genome and its method of increasing in information. Transmission of data through external, non-biological means, is what has allowed the human race to dominate the globe.

The next great change in the series of developments, one most likely be the increase in the information contained by the human genome being altered and shaped by humans themselves. Genetic engineering would allow humanity to alter its encoded genetic information in a useful and highly accelerated way. Humans are to continue expanding their grasp, e.g. in spaceflight, it would be much more effective for them to alter the physical forms in useful ways.

In addition it will become necessary for humans to increase the biological information encoded by their genetic structure in order to allowed to keep up with electronic systems, i.e. computers. Although currently computer systems only encode the informational equivalent of the genome of an earthworm, it seems likely that this will increase minimally until they have reached the informational equivalent of the human brain. As soon as computer systems reach the level of intelligence, they will be able to create systems with greater complexity than their own.

In the human future, even with genetic engineering, there will be a limitation on the possible intelligence of humans. This is, of course, the ability of only a certain size of brain to be birthed by the human form. This limitation could be overcome by creating processes by which humans could be grown outside of the body. Even at this point there will be a limitation: the speed by which the processes in human brains can occur. In comparison with electronic circuits, biological, i.e. chemical, circuits are far slower.

Electronic circuits too will face limitations. Even though the speed by which information courses through their circuits, i.e. the speed of light, is far faster than that by which information travels in human brain, it is still a practical limitation on the potential suite of computers. This could be decreased by decreasing the size of circuits but this too will face a limitation because of the atomic scale of matter.

The current advantage the human brain has over electronic circuits is that it utilizes purely parallel computational methods. Of course, many of the above limitations could be overcome, by interfacing the human brain with electronic circuits.