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Posted: 04 June 2010 06:46 AM   [ Ignore ]   [ # 31 ]
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Just to be even clearer, the claim that “survival of the fittest” is circular is not correct. Fitness is determined by expected likelihood of survival and reproductive success. As George intimates, this is gauged by adaptedness to their environmental niche. It is an empirical matter as to whether the likeliest to survive and reproduce actually do survive and reproduce. To take one example, the large dinosaurs may well have been the fittest members in their niches when the asteroid hit the Yucatan. To take another example, the alpha male in a group might get hit by lightning. The fittest don’t always do well.

The point of “natural selection” is that nature uses a nondirected, noncognitive process of selection, which on average tends to pick out those traits which are best adapted to survival and reproduction in the given niche. But this is only a general tendency and doesn’t always work properly or optimally. ‘Mistakes’ happen, and otherwise less fit animals or traits may be selected for instead.

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Posted: 04 June 2010 07:21 AM   [ Ignore ]   [ # 32 ]
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dougsmith - 04 June 2010 06:46 AM

To take one example, the large dinosaurs may well have been the fittest members in their niches when the asteroid hit the Yucatan. To take another example, the alpha male in a group might get hit by lightning. The fittest don’t always do well.

That does not hold: mouse and rat similar animals were better adapted to asteroids falling on earth; crocodiles, sharks, etc also survived. But the dinosaurs could not cope with it….

I think evolution is more or less the same as Conway’s game of life: the only way to predict the future is going it all through. There is no ‘shortcut’ to predict the future, except letting it unfold. Evolution theory cannot predict which organism will be the most successful, or which become extinct in 100 million years. It is obvious why: we do not know which other asteroids will fall down in the future. But that does not make the theory false, of course.

To George: there is nothing circular in the mechanism, but in my opinion, there is in the definition of its concepts. That does not make the evolution false or anything. I think it is true for all scientific theories, except logic and mathematics.

But this thread is a discussion about time: maybe my evolution example is not quite ok, but I hope you see what I mean. The mass-force example was given by a physics professor in his lecture about fundamentals of physics, so at least that should give no discussion. My central point is that a scientific theory can be circular in his concepts, but as long as its observables are consistent with observation and experiments, the theory is valuable and, at least for the moment, true. Until a better theory comes, that explains more phenomena, or explains it with less assumptions.

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Posted: 04 June 2010 07:22 AM   [ Ignore ]   [ # 33 ]
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dougsmith - 04 June 2010 06:46 AM

‘Mistakes’ happen, and otherwise less fit animals or traits may be selected for instead.

Hmm, if or when an animal is selected it automatically, by a definition, becomes more fit (compared to one who didn’t make it). Therefore I would be more inclined to define “survival of the fittest” those animals who experience greater reproductive success as opposed to those with “expected likelihood” of survival and reproductive success.

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Posted: 04 June 2010 07:30 AM   [ Ignore ]   [ # 34 ]
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GdB - 04 June 2010 07:21 AM

That does not hold: mouse and rat similar animals were better adapted to asteroids falling on earth; crocodiles, sharks, etc also survived. But the dinosaurs could not cope with it….

That’s only correct because you’ve decided to change the fitness calculation. Fitness is determined with regard to a particular niche. The point is that the niche changed because of the introduction of the asteroid.

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Posted: 04 June 2010 07:32 AM   [ Ignore ]   [ # 35 ]
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George - 04 June 2010 07:22 AM
dougsmith - 04 June 2010 06:46 AM

‘Mistakes’ happen, and otherwise less fit animals or traits may be selected for instead.

Hmm, if or when an animal is selected it automatically, by a definition, becomes more fit (compared to one who didn’t make it). Therefore I would be more inclined to define “survival of the fittest” those animals who experience greater reproductive success as opposed to those with “expected likelihood” of survival and reproductive success.

This is not correct, not from what I’ve been led to believe is standard in evolutionary biology. (And it would make “survival of the fittest” into a definitional rather than an empirical matter).

EDIT: for more on this see the talkorigins archive post HERE.

This is all completely OT in this thread, BTW.

[ Edited: 04 June 2010 07:39 AM by dougsmith ]
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Posted: 04 June 2010 07:33 AM   [ Ignore ]   [ # 36 ]
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GdB - 04 June 2010 04:45 AM

No. Time is what makes change and motion possible. Change and motion are the way we see time. One cannot do with the other. We cannot define one concept without referring the other. And that is perfectly OK: it is the same with e.g. evolution and newtonian mechanics.

No, according to the definition, time is what our mind/brain creates to interpret the presence of motion and forces in the universe and the prime mover is the expansion of space. In that sense, it is an illusion.

From the same website on Time is not a dimension

Time is related to the expansion of space. Slower time is associated with slower expansion and negative curvature in space in a higher dimension which was first described by Einstein.  This extra dimension is not a time dimension in which we can travel. Time is just the presence of motion and forces and is caused by the expansion of space.

 

GdB - 04 June 2010 04:45 AM

Critics of evolution say that it is a circular definition: how do you recognise the ‘fittest’? It is the one who survives and replicates. And why do they survive? Because they are the fittest… But still evolution theory is the best theory we have, i.e. that fits the empirical data best (fossiles, DNA etc).

“Survival of the fit enough” is probably closer to what actually occurs in evolution.

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Posted: 04 June 2010 07:44 AM   [ Ignore ]   [ # 37 ]
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dougsmith - 04 June 2010 07:30 AM

That’s only correct because you’ve decided to change the fitness calculation. Fitness is determined with regard to a particular niche. The point is that the niche changed because of the introduction of the asteroid.

What is the definition of a niche?

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Posted: 04 June 2010 07:50 AM   [ Ignore ]   [ # 38 ]
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kkwan - 04 June 2010 07:33 AM

No, according to the definition, time is what our mind/brain creates to interpret the presence of motion and forces in the universe and the prime mover is the expansion of space. In that sense, it is an illusion.

The brain creates the illusion of time, which is a process, a change, which exists in time… Tell me how the brain works, when it does not exist in time. Sorry, it is circular to the bones.

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Posted: 04 June 2010 07:53 AM   [ Ignore ]   [ # 39 ]
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GdB - 04 June 2010 07:44 AM
dougsmith - 04 June 2010 07:30 AM

That’s only correct because you’ve decided to change the fitness calculation. Fitness is determined with regard to a particular niche. The point is that the niche changed because of the introduction of the asteroid.

What is the definition of a niche?

HERE is one definition. I was using it to include the ecosystem or (selective) environment.

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Posted: 04 June 2010 08:22 AM   [ Ignore ]   [ # 40 ]
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Doug,

Just looked in your talk origins link:

‘Fitness’ to Darwin meant not those that survive, but those that could be expected to survive because of their adaptations and functional efficiency, when compared to others in the population. This is not a tautology, or, if it is, then so is the Newtonian equation F=ma [Sober 1984, chapter 2], which is the basis for a lot of ordinary physical explanation.

Interesting that they give exactly F=ma as example… However, I would not say it is tautological, because there is an a in it that can be defined independently of F and m, but it is circular. One needs m to define F, or the other way round: m=F/a.

I am wondering if it is possible to define a niche without reference to survival, even if it is hidden behind a lot of words:

The ecological niche describes how an organism or population responds to the distribution of resources and competitors (e.g., by growing when resources are abundant, and when predators, parasites and pathogens are scarce) and how it in turn alters those same factors (e.g., limiting access to resources by other organisms, acting as a food source for predators and a consumer of prey)

(From your ‘niche link’)

What is the difference with ‘environment where the species can survive’?

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Posted: 04 June 2010 08:23 AM   [ Ignore ]   [ # 41 ]
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GdB - 04 June 2010 07:50 AM
kkwan - 04 June 2010 07:33 AM

No, according to the definition, time is what our mind/brain creates to interpret the presence of motion and forces in the universe and the prime mover is the expansion of space. In that sense, it is an illusion.

The brain creates the illusion of time, which is a process, a change, which exists in time… Tell me how the brain works, when it does not exist in time. Sorry, it is circular to the bones.

GdB

As I quoted in my last post:

Time is just the presence of motion and forces and is caused by the expansion of space.

This is just what time is, if the writer is correct. Our mind/brain interpret that as “time” with the properties of past, present, future and the flow of “time”, which is an illusion. This is not circular. In other words, we exist in a universe which has the “presence of motion and forces caused by the expansion of space” which we think is “time” and that is an illusion.

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Posted: 04 June 2010 08:30 AM   [ Ignore ]   [ # 42 ]
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kkwan,

But then the brain is an illusion to, because it exists in space and time. And even if the mind cannot be localised exactly (it is ‘spread over the brain’), it at least underlies the change in time as well. No time, no change; no change, no time.

And locally, space does not expand. Until the size of a cluster of galaxies, everything is held together by gravity.

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Posted: 04 June 2010 02:34 PM   [ Ignore ]   [ # 43 ]
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kkwan - 04 June 2010 02:54 AM

I wanted to start a post on time in the philosophy section, but it is convenient to tag on to Doug’s post here, because the nature of time and how we experience time is essentially a metaphysical query. Science only considers time as a sequence of moments in a linear order (clock time) and scientists normally do not consider other concepts of time. OTOH, we subjectively experience time as a sequence of “presents” and the “flow” of time as non linear. We intuitively know that we cannot change the past (we can only remember it), but we can change the future (free will) by what we do now. However, we cannot stop the “flow” of time. We can stand still in space (wrt to the earth), but we cannot stand still in time (wrt to anything). Why is it so?

I just googled this:

http://serendip.brynmawr.edu/local/scisoc/time/chennotes.html

1) The Conventional View
“In daily life we divide time into three parts: past, present, and future. The grammatical structure of language revolves around this fundamental distinction. Reality is associated with the present moment. The past we think of having slipped out of existence, whereas the future is even more shadowy, its details still unformed. In this simple picture, the “now” of our conscious awareness glides steadily onward, transforming events that were once in the unformed future into the concrete but fleeting reality of the present, and thence relegating them to the fixed past.”—Paul Davies, “That Mysterious Flow”

I wonder what one could want to understand about time more than the mysterious flow? Is it an illusion? If so where does it come from? Would we find some amazing stuff out about consciousness by finding out? Equally what if it’s not an illusion, then would we find some amazing stuff out about consciousness and the universe?

What question about time could be more interesting for philsophers and scientists alike than the question of “the mysterious flow”

I suppose what I’m really questioning here is the indifference to the question on this thread, as if it’s not significant, and as if it’s not to do with science.

Stephen

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Posted: 04 June 2010 09:15 PM   [ Ignore ]   [ # 44 ]
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GdB - 04 June 2010 08:30 AM

But then the brain is an illusion to, because it exists in space and time. And even if the mind cannot be localised exactly (it is ‘spread over the brain’), it at least underlies the change in time as well. No time, no change; no change, no time.

And locally, space does not expand. Until the size of a cluster of galaxies, everything is held together by gravity.

Not so. The mind/brain exist and it can be shown that it is so and it is not the creation of some other sentient entity. The universe constantly changes under the influence of motion and forces and the expansion of space. An unchanging universe will be timeless.

Locally, even though space is not expanding, there is still motion and forces (after the Big Bang) which is change. Gravity is the dominant force locally.

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Posted: 04 June 2010 10:22 PM   [ Ignore ]   [ # 45 ]
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StephenLawrence - 04 June 2010 02:34 PM

I wonder what one could want to understand about time more than the mysterious flow? Is it an illusion? If so where does it come from? Would we find some amazing stuff out about consciousness by finding out? Equally what if it’s not an illusion, then would we find some amazing stuff out about consciousness and the universe?

What question about time could be more interesting for philosophers and scientists alike than the question of “the mysterious flow”

I suppose what I’m really questioning here is the indifference to the question on this thread, as if it’s not significant, and as if it’s not to do with science.

If time is “just the presence of motion and forces and is caused by the expansion of space”, this would explain the flow of time and it’s direction. After the Big Bang, space expanded continuously and is still expanding (flow of time). Expansion is unidirectional (the arrow of time).

If time is just “the presence of motion and forces caused by the expansion of space” and space can expand faster than the speed of light, how and why is it so and what are the implications for the “speed” of time?

Scientists and philosophers consider time from different perspectives. Scientists use the operational definition of time.

From the wiki on Time

An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life.

OTOH, philosophers are interested to find out what time is, metaphysically. Philosophy is not science and does not need to adhere to a operational definition of time. From the same wiki:

Time has been a major subject of religion, philosophy, and science, but defining it in a non-controversial manner applicable to all fields of study has consistently eluded the greatest scholars.

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