Keith

Yes.

Keith

Keith

Now you're admitting that nature does display purpose even if we don't understand, or we mis-read what that purpose is. I completely agree. And I would add that traits that serve to facilitate the survival of a species obviously do serve a purpose.

Keith

Keith

Functionality only reinforces my point. We can have reasonable differences of opinion as to some object's purpose, but to conclude from this (that for some objects we cannot be certain of its purpose) that the object under consideration has no objective purpose does not follow.

Keith

Keith

You've just made my point far more eloquently than I have, or could. Thanks!

Keith

Keith

How can be know this? You are claiming to understand the goal--making changes that are going to be useful now. If you understand the goal, then there must be a goal. And of course, if evolution has a goal, it would be contradictory to also say that evolution is a purposeless process.

Keith

Keith

I forgot what it is you are saying I'm supposed to define. Regarding sieves, most people would probably say that a sieve has a purpose. Question: does an evolutionary "sieve" have to exist, or is it just something that happens for no particular reason?

Keith

Godless Dave

What you mean by "purpose"

I would say it doesn't have to exist, but there are reasons it happens.

Starboy

What purpose would the eyes and ears serve and whom would they serve?

Starboy

Monkeybot

I'm going to repeat what MyKell said. We're getting tripped up in the language here.

Keith, what exactly do you mean by "purpose"?

It seems like you are using two definitions interchangeably:

A) Function: "The purpose of my eyes is to see."

B) Goal: "My eyes developed with the purpose of allowing me to see."

A is pretty much a no-brainer. An empirical fact. Eyes see. Ears hear. Nobody really questions this.

B is a lot more debatable. In fact, I'd say it's dowright false. I didn't choose to have eyes, species didn't choose to develop eyes, nature didn't consciously up and decide to give them to us, and no platonic ideal of "eyes" was floating around waiting to come into being.

The entire concept of "choice" is an illusion here. Organisms just happened to, at some point, develop light-sensitive areas of their bodies. The organisms with these light-sensitive areas had an advantage in finding food, avoiding predators, and reproducing. Their genes (which included the package for light-sensitive organs) were passed on in greater frequency. Their light-insensitive counterparts, meanwhile, had LESS success in surviving and reproducing and died off in greater numbers. So over a few generations (I don't know how many, this is a really generalized example), you might go from a majority of light-insensitive animals to a majority of light-sensitive ones.

What is the purpose of that? Do you see any conscious selection at play in that example?

Happy Wonderer

Maybe to expand -- in my back lot are trees that have been affected by various windstorms. Many have fallen and been converted to firewood. Some have leaned massively and tangled their upper branches with other trees. Some are supported to an extent that they have been able to survive this way for several years.

One function of the upper branches of these leaning trees is now to support the leaning tree -- if I were to (foolishly) cut those branches the trees would fall (and me with them.) However, one certainly couldn't argue that the purpose of upper branches was to 'grabbing neighboring trees in case a windstorm comes along.'

Or perhaps another way of looking at it. Keith's function at the moment is to relieve the boredom that has been prevalent in the E/C forum recently due to a lack of theists challenging evolution (Thanks Keith!) I doubt that is his purpose.

To segue back into bats, echo-location clearly evolved from functions that other mammals have -- sound production and sound reception. It is not that big of a stretch for a mammal given the properties of sound. Before radar, ships on this coast used to blast their horns in the fog in certain of the fijords here; the length of time it takes for the sound to return would be used to estimate how close to the cliff you are. It isn't all that complicated: long time between sound and echo = far away. This is an example of dual-use; foghorns are used to warn other ships of your location but also have the property that they can help with echo-location in some situations.


HW