Parallel Evolution

There is a biological concept called parallel evolution which refers to the phenomenon by which the same trait is evolves in the same manner in two different species. For example, all eyes came from the same base creature. But eventually marine and vertebrate animals both evolved the same set of eye advancements, despite lacking a common ancestor that had all those advancements. There are also cultural examples of parallel evolution for concepts like writing and the wheel. In each case, these concepts fit three basic criteria:

• Very useful when obtained
• Not completely obvious
• Little to no room for implementation differences

The key point is the last one. There's just one way to do a working wheel or for writing to work, so in that respect it's not surprising that the ancestors of the Mayans and the ancestors of Chinese came up with the similar concept of putting symbols on surfaces to record concepts. (And yes, the wheel is not a completely obvious concept, because it also requires the design of an axle.)

So I often wonder what an alien life form would be like, evolved totally independent of life on Earth. What concepts are there about life that really only have one good solution? For example, the structure of the carbon atom makes it highly likely that all life would be carbon based. It's theoretically possible to have silicon based life, because carbon and silicon have similar structures (both have four possible atomic links), although silicon is much heavier, but carbon is by far the most likely. Also, water is a fascinating molecule in liquid form, used for a variety of purposes in life, so it would be very surprising to see a life form that did not use water.

All of life exists somewhere in the density spectrum between water (liquid) and carbon (solid). Some are closer to the water side, like a jellyfish. And some life forms are closer to solids, like trees. Land based animals ("fleshlings") are in the middle, and seem to offer a good mixture between the mobility of a jellyfish and a protective shell of a tree. So it seems likely that any sentient life form will be made of some kind of flesh.

So while we can guess about the physical form of another life form, deducing the nature of an alien brain is much harder. That's primarily because we don't know enough about the human brain to guess which features only have one simple solution. We've only encountered one kind of sentient life: humans ourselves. Would aliens need to sleep? Our research into sleep implies our brains use sleep to process memories, similar to defragmenting a hard disk. Important memories are stored, unimportant ones are discarded. But is our brain's implementation of memory the only way to solve this problem?

Well, computers solve the storage of data-- thoughts and memories-- through completely different means. Human thoughts are fluid. People can easily forget things that happened five seconds ago, or even remember the details incorrectly. Even photographic memory isn't perfect, and seems to decay with age. Short of hardware errors, however, a computer's memory management is perfect. All the data can be retrieved without error. The human brain seems to sacrifice accuracy for much greater storage capacity, access speed, and perhaps processing speed. It's possible there exists an alien life form that has found a solution to the memory problem that incorporates human memory capacity with computer memory accuracy, but I doubt it.

So this line of thought makes me think two things about the field of AI research. The first is that it's crucial to identify the portions of intelligence that only have one good solution and solve them first. For video game AI, these are problems like navigation and visualization. At this point everyone knows the navigation solution is A*, but there's still the question of how the mind identifies the potential way points A* requires. For general AI, the most fundamental problem is language processing, which is devilishly difficult and could take centuries to solve. But having a library of known solutions to basic AI problems will accelerate the ability to create good AI. This is similar to how an operating system abstracts away simple solution to problems a programmer doesn't want to worry about very much, such as processor scheduling and disk space access.

The second thought I have is this nagging feeling we may be designing AI on a fundamentally flawed hardware platform. The computer is excellent when what you want is ultimate precision. Designing AI on a computer involves writing sophisticated algorithms to artificially create the "randomness" that real life seems to incorporate. Perhaps one reason artificial intelligence is so hard is that sentient life requires a system of memories that trades precision for increased data capacity and faster access time the way a human brain does, and we'll never create satisfying AI until we start programming on that kind of a hardware platform. I don't know if that hardware platform is still based on transistors or if it's something more like DNA, but deep down I feel like designing AI on a computers is pushing a square peg into a round hole.