Evolution and complexity

What you have described is "information" not complexity.Information is very high in a completely random string and very low in a monotonous repetition. However, a random string has something missing. It is not as "interesting" as the bits of a computer program which may have high information content and even look random. But it is not random, it has some meaning in the right context.The word "complexity" is an attempt to capture this extra idea which is different from the Shannon information. I don't know a lot more than that but it is, apparently, hard to get a good definition of "complexity" so that it may be quantified.I'll let you know if I find something.

---

Common sense isn't

Nice analogy, Mr Jack. I think it might help some understand the message.

---

Common sense isn't

Welcome here SaviorMachine.I do have to say that I find your post rather rambling. It does? You'd have to define complexity to me to convince me. And "often" is a bit of a waffle here isn't it? How often is that?The last paragraph I just don't follow. Sorry

---

Common sense isn't

Since this thread has complexity in the title I would think that complexity would be defined. So far it has been defined synonmously with information. I think we might find that to be unsatisfactory.Can you define the term you are using and diferentiate it from information?Given one level of complexity of life then making random changes to it offers a wider range of choices in the population. I presume that this results in an increase in complexity in your mind. Is that correct? This complexity is in the overall population of course.If we have two organisms of identical complexity and they both have offspring that are not identical to the parent is it not likely that some of the offspring will have a different level of complexity? If not why not?If these kind of changes in complexity keep occuring then the total complexity of population could well be higher and also of individuals.Is there something wrong with this? Since I don't know what you mean by complexity I can't tell for sure.

---

Common sense isn't

I'm not sure you can make this statment so easily. For one thing do we know that a microbe today is necessarily more complex, however you define it than a microbe 2 billion years ago?Is a bird more complex than a theropod dinosaur?I would expect that the average complexity of all life on the planet hasn't changed much at all in some 100's of millions of years. It may be that, depending on how you calculate complexity it hasn't done more than nudge up a percent or less in the last couple of billion (on average, remember).

---

Common sense isn't

Lol, I think I beat you too it by 30 seconds Crash.

Sure. However you choose to define complexity I'm sure there are some mutation and/or other genome changes (I'm not sure adaptations is the right word here but it may not matter) that would be a complexity adder. OK, now what?

But you haven't defined complexity yet.We haven't agreed that complexity as gone up all that much.These questions don't make any sense until you define what you are talking about. Starting from the KT boundary; is an elephant more or less complex than a triceraptops? How would I tell? How much more or less complex?I gave you that some changes add something you call complexity. I didn't say that everything is more complex now than at some point in the past.Why do you think there has been some large change in some quantity you haven't yet defined? Even if there has been some significant change in overall complexity there are several billions of attempts a year to get that increase (make that trillions) as each living thing is a new chance to have a complexity increasing change.[This message has been edited by NosyNed, 02-06-2004][This message has been edited by NosyNed, 02-06-2004][This message has been edited by NosyNed, 02-07-2004]

So complexity is just information times a constant of some sort? But then a completely random series has maximum complexity by the information theory definition. I don't think that is a useful defintion. In fact, that is why there are attempts to define complexity in some rigorous way that also meets our intuitive understanding of it.For our purposes here you have not defined anything new. Increase or decrease or staying the same we can't tell if we can't quantify what we are talking about.I would suggest that a good guess is that from the KT boundary(at least) forward "complexity" has had about the same maximum. The overall biosphere "whatisit" has probably gone up if you start from right after the KT boundary ( I think a kazillion megatonne blast would simplify things a bit) but probably not changed a lot since a time just before the KT boundary.I'll offer reasons why I might guess this if you will define terms. Uh, there is a small matter of some 10's of Myrs between the KT boundary and paleomastodons. I would guess that any of the elephant relatives over the last handful of millions of years are genetically within a few percent of the same as modern elephants and closer than that in genetic "information content". You are doing more than coupling so far. A simple constant in the definition keeps complexity conceptually the same as information just in different units.If we use genetic information content as the measure then we know that not all creatures are the same. We have bacteria with 100's of base pairs in their genome's to creatures with billions.The rest of the post doesn't seem very relevant since any mutation that isn't bad enought to be selected out adds to the total information content of the population genome (and that is a large fraction if not the majority).(Note: in all the above I'm using numbers of base pairs as a quantifiable measure of something. I'm using the word information because I think it is at least intuitivly correct. I didn't follow the "information in DNA" well enough to know if it is technically correct. Until I get something else to quantify I guess that will have to do.
Note: If we are talking about increase,decrease then we are talking in quantitative terms so we needs some kind of measure.)

Yes, that is why "information" content of the genome (or of anything else is not a 'well-behaved' measure of complexity.So you are not, in fact, talking about anything 'proportional to information'. Whatever complexity is it isn't as you've defined it there. I will look at the post 23 and 26 information tomorrow. I'll have to ask you some more questions about your types later. I don't see why you have them all mixed together.How do I measure variablity in the natural environment? Has it increased, decreased or stayed the same over the past 50 million years?How do I distinguish between the amount of variety and genetic material in a population? Why is it necessary to add up the total number of base pairs in a population? Do I cross species lines when I do that? What is variety? Is that a synonym for information?

Oh, I was about to say what rats? But now I have a vague memory on that. It was weak warfarin resistent rats wasn't it.Thanks. You obviously have a better memory than I. I might just lend you money.

Ok, I'm going to have to do a bunch of careful reading. I'm a bit busy so it may take a day or so.

Kolmogorov complexity is, as best as I can tell, not the same as information and not proportional to information.You need to decide what measure of complexity you are going to use. In your other examples (types 1,2,3 and 4) you use information.This whole area is quantitative. You can't make any progress without being precise.yes, I agree that biological systems are some kind of "complex".[This message has been edited by NosyNed, 02-12-2004]

Well, I think that is a very good thing to do.However, neither of us has to "believe" anything.First we need a clear definition of complexity then we have to see if we can demonstrate that evolutionary processes can or cannot account for changes in it.As far as I can tell any definition you have given so far is accountable for with darwiniam processes.

How do i calculate the "density"? This just introduces a term that isn't defined either. It seems to me, at first glance, that a completely random pattern would have the maximum density.As I noted elsewhere, the problem of defining complexity so that it fit with intuitive ideas of what it should be and doesn't reach a max on a random pattern is hard, or so it seems.Until I see a useful definition I don't know how to proceed.