Information and Genetics

quote:

---

Rei, this is so bizzare I cannot put it into words. I hope you are simply misunderstanding my argument, so I will try one last time. When engineers at GE set up the commercial GA to aid in producing a more efficient compressor, were they determined to use the result no matter what it produced? Yes or No.

---

Do you actually think that a design team of any kind will be "determined to use the result no matter what"? I have preformed a lot of software design and we frequently throw out the result of the design efffort when we realize it isn't going to be suitable.Why do engineers produce prototypes? To find out what is wrong with a design and correct it for one thing.Do GA's produce usable designs? YES.

I am trying to sort out what Fred is having trouble with here. Fred, excuse me if I get this wrong but I am going to try to word your arguement for you. If I inadvertently setup a strawman while doing so please correct me.Fred is saying that there has to be intelligence put into (or built into ) the GA use for it to work. Exactly where this is he hasn't made clear. So let me try.For a GA to be run there has to be computer hardware and software that is build by an intelligence. In addtion, the GA itself is designed by someone. I think he is saying that this is where the intelligence is needed. Do I have this right Fred? Is there anywhere else that you think it is neeed?The analogy here is that to "run" evolutionary processes we need a physical universe and it's laws. For evolution to take place we have to have replicating things with selection taking place. These requirements are, to me analogous to the "intelligent" input to the GAs. If this is the case, Fred is agrguing against the GAs, by analogy, by arguing against the big bang and abiogenesis I think.Do I have this at all right, Fred.(edited to correct one of the spelling errors -- the others are left as an exercise for the reader)[This message has been edited by NosyNed, 09-28-2003][This message has been edited by NosyNed, 09-28-2003]

You are right, I was thinking too conventionally. With the GAs used this way, of course, almost by definition, the output would be used.I don't know enough about them to have a reliable opinion I suppose. Is it not possible that after a solution is reached it may still be rejected? For example you might produce software that, while "better" than you might have designed, may be so complex (as evolved things in nature tend to be) that you might not want to maintain it?

And it was I who later realized I misunderstood the nature of the use of the GAs. In this case, they produce a better result so, of course, they will be used. Rei is, after all, actually working in with these things.Separately from that you have not shown that they don't emulate evolution. Any objections I have seen you raise seem to have been answered.

Fred, I don't know the GAs that are being talked about (none in fact) I just have a rough idea of how they work.I sit back and see two camps making very specific statments about speicific GAs and their use. Why are these apparently basic facts being disagreed about? For example, the truncation selection issue. It looks like, when I read the back and forth, that it has been explained and it is NOT an issue. You say it is?Could you explain that please using a much more detailed description based on your knowledge of Avida and what settings it has and how they work. This will help all of us, since you and the others all know Avida already and the rest of us watching the discussion don't and therefore don't get what is being said properly.Rei, has been making specific factual claims about GAs. In the details of how they work or may be used. Exactly what is untrue about those.The bit about the engineers using the output was explained very clearly by Rei. This insight into the nature of their use enabled me to understand what was being said. I don't know why you don't understand that.As I understand what was said, there are cases where the GAs are only going to produce better results with each "generation". The decision has already been made to use the GA as a tool to solving the problem at hand. This decision has already considered issues like the nature of the result (not maintainable if it is code for example). Thus, obviously the output will be used. What do we disagree on on that?

I'm sorry to take someone's time, but could someone post a description of what "truncation selection" is and why it is an issue here? It would help those of us who are not cogniseti like Fred and Rei to understand the points being made?

Yes, thank you. I understand better now. But let me try to phrase it in my own words to see if I understand.In real life, individual organisms have different phenotypes and there may be some of those that are an advantages or disadvantages that natural selection may act on.When a GA is set up it employess evolutionary mechanisms to allow novel outputs to evolve. These include some way of generating different "organisism" and some way of selecting them.In real life, organisms may die by purely random events that have nothing directly to do with there phenotype. (e.g., an asteroid landing on you). In the GA this fact of life may or may not be used. If only the criteria that define "better" are used to select then we have truncation selection. If instead a mix of randomness is used to kill of "organisms" we do not have truncation selection.It seems to me that this isn't either or. There is some parameter that specifies the amount of influence that random death will have or there should be such a parameter to allow one to use the GA in a variety of ways.If I'm in a hurry I turn the randomness down and get truncation selection, if I'm more interested in simulating "real life" I turn it to some other value. E.g, "real life" at the end of the cretaceous had a very suddenly large random component.(as an aside, in real life, is there ever a really random component. The creteaceous extinction appears to be random relative to long term evolutionary pressures, but isn't it really a sudden change in the nature of selective pressures? After it being small and a scavenger may have been a great survival advantage. Isn't it always "truncation selection"? That is selecting for what is desired? But nature keeps changing (slowly or quickly) what is "desired"? )

I agree. Isn't the point that complexity can arise from things which model the evolutionary process? It seems to me that creationists insist that no such compleity can arise from any "random", unguided process. GA's show that this statement is false.Creationists also specifically insist that life 'as we know it', could not arise from such a process. The GA's do not precisely show that this statement is false. They do not perfectly model the unfolding of life on earth.However, given the degree to which GAs do produce novel results of some complexity they do strongly "suggest" that evolutionary process might be capable of producing life as we know it. And we are left with no good argument as to why we shouldn't go with that suggestion.Darwin said that processes of this kind would produce diversity and complexity. He could not test that directly in the lab. We can now and his prediction has been fulfilled.To rebut this wouldn't someone have to say exactly what the process is and why a particular model of it isn't close enough?Fred seems to have attempted to rebut this without being clear on what he thinks a "real" evolutionary" process is like and why, in particular, it has not been modeled.He has, to me, made statments about one use of a GA as if it applied to all uses of all GAs. This doesn't, to me, rebut the point being made.