Sunday, May 29, 2005

Short Article Critiquing Intelligent Design Movement

A very nicely written, well argued, piece on why the Intelligent Design movement has a flawed and rather underhand modus operandi.

Monday, May 23, 2005

Requirements on Understanding for Software Brains?

Ricky writes: "Until we fully understand how the human brain operates, I don't see how it is possible to download somebody's mind and have it do anything constructive."

Ray Kurzweil believes that we can do it without needing to understand how it works. He thinks that if we can have high-enough resolution scanners, such that we can get an accurate scan of the physical structure of the brain, we can -- basically -- encode and simulate that structure within a computer. Doing this would of course require a suitable understanding of the way the low-level physical structures work, but it would not require an understanding of what the actual neurones and higher-level structures were doing.

Do I think this is possible? I don't know whether it is possible, but I'm not aware of anything that could rule it out. That is, it seems to be a matter of "we'll have to wait and see".

Perceptual Adaption At Work

Just a quick observation... I often work on my PhD stuff at a local coffeeshop, and sometimes it's a bit nosiy so I listen to music on headphones...

at first I have to have the music fairly loud to block out the other sounds enough but there's a quite noticable difference that occurs after some amount of time -- I dunno, maybe 5-10 minutes -- where the music sounds a lot louder and I can turn it down a fair bit but still effectively block out the sounds.

The transition is not that noticable, but that there has been a change (no doubt a gradual one) is. What seems to be happening is that my brain is adapting to the headphone sounds, and getting better at focusing on them and at filtering out the other sounds.

Sunday, May 08, 2005

Re: Language for Talking, and Thinking, About Evolution

A reply to a comment from Bevan on my last post:

>Some interesting thoughts here James, I've got some of my
>own opinions :-).
>In the first section (situation instead of environment) I
>would more carefully consider who is using the term
>environment when analysing the correctness of its usage. I
>certainly consider environment to be more than the physical
>landscape. My housemate for example is doing her PhD in
>ecological modeling. She (and people in similar fields) do
>use the term environment correctly. Factors such as
>biodiversity, population distribution and the presence of
>predators / prey are all important consideration for them
>when talking about environment. You are certainly not going
>to convince them to change their correct use of environment
>to situation because a portion of population use the term
>incorrectly. Isn't it a matter of educating / correcting
>people on the proper meaning the of term rather than consider
>it tainted and ditch it for a new one?

I don't want to imply that nobody uses it correctly, but I still think that in practice people -- even some experts -- think of the envrionment in a too narrow way (regarding my note of 'even some experts', I think, for example, that some such mistaken thinking by experts was cleared up by John Maynard-Smith's Evolutionarily Stable Strategies (except I don't think that article describes it very well, but it was the best link I could find) concept).

If this is the case then of course their notion of 'environment' needs correcting. But with respect to describing evolution, I think that even if with a proper understanding of 'environment', the notion of 'situation' is a more /appropriate/ (not more correct) term.

I should also make it clear that I'm not trying to change anyone else's vocabulary, I'm just trying to figure out what I think is the clearest way of thinking about these concepts.

>Regarding the use of increase and optimise - note the s not
>the z you seppo :-). I agree that changes due to natural
>selection is better expressed using "optimise" rather than
>increase. There are however cases where an organisms fitness
>does increase due to natural selection. If a change in the
>organism results in that organism being far more successful
>in its environment does this note denote a increase in the
>fitness with respect to that environment? Success can be

I don't have any problem with the concept of fitness as something that can be increased or decresed. I think that optimisation -- with an 's' just for you! :-) -- leads to increased fitness. I think that it can cause problems however, to characterise evolution as a process that "increases fitness".

I think that doing so paints a picture of fitness as something like a numerical quantity that can be increased or decreased, and where you can compare these numerical values across different environments and species. I think that talking of evolution optimising fitness helps avoid these problems. Any particular optimisation will lead to an increase of fitness. But there's no universal measure of fitness that is you are constantly bumping up.

I think it's easy to misunderstand this point, and think that it implies some sort of extreme "fitness relativism" where there's no means to make any comparison in terms of fitness or in terms of other concepts such as "sophistication" or "complexity" of design.

Fitness may be relative to situation, and no two situations may be /completely identical/, but situations can share a lot of similarities. After all, every situation in this universe is under the same laws of physics (or at least I don't think we have any reason to believe otherwise). And there are surely certain types of abstract problem solving abilities that have a very broad range of applicability, to give another example.

>measured in a number of ways of course: population density,
>height in the food chain, susceptibility to harsh
>environmental changes, etc. Take the example of a carnivore
>diversifying its diet to become an omnivore. This will likely
>come about due to changes in its environment, e.g. lack of
>prey. If by widening its diet it really begins to flourish
>could this not be called an increase in the fitness with
>respect to its environment?
>There is some really good reading about this: Carl Sagan's
>book Cosmos (first 50 pages for so I think) has a very good
>argument for natural selection and explanation of how it
>happens. Jared Diamond's books 'The Rise And Fall Of The
>Third Chimpanzee' and 'Guns, Germs And Steel : A Short
>History Of Everybody For The Last 13,000 Years'. For
>something easier and more entertaining I've got the David
>Attenborough's 'Life of Mammals' DVDs. They've got some
>interesting explanations about the evolution of mammals.

Ah, all books that I would like to read but haven't yet :-). "Guns, Germs and Steel" in particular.

>Good luck with the PhD...


Wednesday, May 04, 2005

Language for Talking, and Thinking, About Evolution

A lot of people recognise that the language we use to talk about evolution is, if taken literally, quite inaccurate. The following are some musings, hastily written up, on how to more accurately describe what is going on. I haven't thought these things through much, and I haven't really looked at whether the suggested alternatives would be suitable for practical situations (like considering whether they are too unweildly or not).

Use 'Situation' instead of 'Environment'

We talk of the creature's environment setting up the selection pressures. Properly understood, there's nothing wrong with this. At the same time, I think the conception of 'environment' most people have can mislead them when thinking about this. The term 'environment' can conjure up the environment of the landscape around the creature, the other plant and animal species. That it can tend to obscure is that the other members of the same species are part of the environment, and that the results of the creatures own behavior is also part of its environment. I think it can also obscure the fact that the environment is not just the physical place, but the unfolding and changing environment over time (over time the selection pressures will change). For these reasons, I think the reality is better captured by the term 'situation'. The creature's situation sets up the selection pressures.

Use 'Optimize' rather than 'Increase'

We tend to say that evolution works to increase a entity's fitness. I think there are two reasons why this can be misleading. It implies that there is some one dimensional value that is being increased... which is okay if you understand that value as an "abstract" fitness. It's just that it doesn't capture well the multidimensionality of the factors that actually make the difference to survival and propagation. "Increase" also suggests a ladder and some path of progress... but this is a bit misleading. For fitness is always relative to the current environment, and what is fit will change as the environment changes. It is not so much that we have steadily increasing fitness, but that the system's fitness "tracks" the changes in the environment. (this is not to say that because 'localized changes' don't always lead to greater general sophistication the biosphere will not end up creating greater complexity over time). For this reason, I think that it is better to talk of creatures fitness being continually optimized rather than continually increasing.

Talk of Natural Selection and Evolution as Products Not Forces, and of optimization potentials instead of implicit goals

When we talk of evolution at work, we tend to say things like "evolution created eyes so animals could hunt their prey". This language is inaccurate because it implies there's an active force pushing, or trying to push, the evolution in a particular direction. But natural selection and evolution is not so much a force that does things, but the product of certain types of situations.

It's the product of situations containing the three factors of variation, heridiblity of that variation, and, basically, competition for survival. When these three factors are present, natural selection and the evolution of forms are the consequences. That is, the natural selection process and the evolution of forms are emergent phenomena.

I started reading Stuart Kauffman's At Home in the Universe last night, and I think there is some of this confusion about evolution in his consideration of how self-organising systems relate to evolutionary processes, though I don't have time to go into the details here (so you can ignore this statement if you want :-)).

We talk of creatures, or evolution itself, evolving some feature for some purpose. This is really just a way of talking and is quite inaccurate. Creatures can't direct their evolution like this, and neither can evolution itself. Evolution does not have goals, and even if it did, it doesn't have any foresight that it could use to reach them. (thinking about evolution as if it did have goals and/or foresight seem to be very common problems). We can much more easily see this when we understand that natural selection is an emergent phenomenom, and I think part of the reason this problem occurs is because of seeing it as some sort of force at work.

It seems difficult to talk of evolution without talking about goals. We talk of evolution as coming up with solutions to problems (it's goals are to solve those problems). What's really going on, however, is that a particular situation provides certain opportunities for creatures to evolve in certain ways. That is, in any given situation, there might be various ways that a creature could potentially evolve that would improve its fitness. If the appropriate mutations happen to occur, the species will move in one or more of those directions. So it's not so much that there is a problem to solve -- a goal to be attained by solving it -- but that the environment possesses opportunities that creatures can happen to evolve towards. I would describe these opportunities as optimization potentials (and remember of course that any change in the environment, including the evolution of a particular species, may change the optimization potentials for it). So natural selection may end up meeting optimization potentials. So perhaps you can say something like "the unfolding situation made use of an optimization potential to evolve feature Y in Xs".

So we can say stuff like "The situation selected for Y", "Optimization emerges from a situation", "Xs evolved feature Y by natural selection's optimization".... but as I said at the start I haven't really thought about using this language in a practical context... and I don't have time for this right now.