I just read a very interesting interview with David Deutsch about the multiverse. Deutsch is a physicist who studies quantum mechanics. One of the craziest (but best proven) laws of quantum physics is the way photons and electrons behave both as a particle and a wave at once. In the famous experiment with light going through two slits, photons interfere with each other as if a wave and create an interference pattern. They do this even when only a single photon is sent through at a time and even if a detector is setup to see which slit each photon went through. Somehow even single photons are interfering with something. Deutsch’s explanation is that the photons are interfering with other photons in other universes (the multiverse). He then suggests that since we are made up of small particles like this, the same thing must happen to us as well. Therefore there are many parallel universes where we all exist.

Deutsch’s explanation of the light experiment is intuitively appealing to me. The traditional explanation of this sort of thing in quantum physics is that the particles exist as a probability wave which collapses to single point (or particle) when you view it. But the idea of particles as probability waves and our viewing affecting it is very awkward. The idea that the particle is interfering with infinite numbers of particles in other universes makes intuitive sense to me. And the extrapolation that even people are existing in multiple parallel universes is an interesting one.

In our reading group this week, we read John Searle’s classic paper “Minds, Brains, and Programs.” In the paper, he makes the claim that digital computers doing symbol manipulation cannot have intelligence. His motivating example is what he calls the Chinese Room Experiment. Basically, a man is inside a room. He is given a set of instructions to follow when he receives papers full of Chinese symbols. By following the instructions, he creates a second set of symbols which he returns. Although he does not personally understand Chinese, to an observer outside the room, they have just received fluent answers to questions in Chinese. Searle claims that this shows that intelligence cannot be created in a digital computer (the man) with a program (the instructions) because in this example the man clearly does not understand Chinese. I would argue that the room as a whole understands Chinese, as its the whole system that understands it (you wouldn’t expect a computer to be intelligent without its program). He argues that the system as a whole cannot have intelligence, and that some subsystem must have it. But the same systems rule applies to the brain, the brain as a whole has intelligence, but you can’t ascribe the intelligence to any subsystem of the brain such as a neuron or brain region.

The other main thing that bothers me about Searle’s essay is that he claims that human intelligence can never be replicated on a digital computer because a computer does not have the same “causal properties” as the brain. He claims that our intentionality is somehow created by these “causal properties” inherent to the brain that cannot be replicated in a computer. He makes no claim as to what they are or why they can not be replicated. I find it highly unlikely that our intentionality is due to some specific physical feature of the brain as opposed to an emergent property of the coalition of neurons in our brain. It seems like Searle is searching for some little homonculi in our brain that is directing things, and that we can’t recreate that homonculi in a computer. But there is no little man inside our brains.

One interesting point that Searle brings up is the separation of mind and brain. The separation of mind and brain may not be the same as the separation of a program and a computer. While a program can be run on any number of equivalent computers, the mind may be dependent on specific properties of the brain, or may be integrated in the brain rather than being some program that can be applied on top of the brain. I can agree that there are probably some aspects of the brain that are essential to mind, although I don’t see why we won’t be able to simulate those somehow in a computer.

In this talk, Seth Lloyd talks about the universe as a giant computer and the implications of that notion.  As I’ve described before, the universe is a giant computer because all of the atoms and molecules in the world represent information through their various qualities such as spin, etc.  Every interaction between atoms or molecules is, in fact, a computation.  Since the universe is infinite, this giant computer will compute everything possibly computable.  Since a computer can simulate any other computer, this includes computing more computers.  Namely, us.  As the universe computes all possible computations, some of this create increasing complexity, eventually leading to bacteria, animals, humans, and the computers we have today.

I find this idea pretty interesting.  In essence, the universe is a giant computer simulating us (who are also computers).  You hear about this philosophical “Brain in the Vat” question where we may just be brains getting simulated inputs and outputs from somewhere (the Matrix).  This takes it to a whole new level, essentially our whole existence in the universe is inside a giant computer that is computing everything.

Here’s an interesting article by Freeman Dyson on “Our Biotech Future.”  Basically he predicts that we will soon have personal biotechnology devices and all be able to be genetic engineers.  He suggests that this will create solutions to many problems and also perhaps help eliminate poverty.  One aspect that I found particularly interesting was that with this genetic engineering, there will be more competition between genes of various species.  So perhaps this new era of personal biotechnology would lead to faster evolution?  Although instead of being guided by Darwinian evolution, gene selection would be guided by lots of genetic engineers.  It certainly could result in some interesting (or dangerous) things.