Quote from: Jon on February 17, 2009, 04:07:31 PM
I disagree with your definition of "random." Evolution is heavily directed and constrained by myriad events that are not very predictable, but "random" has a meaning and implication that leads one to logical fallacies if it is used to describe Natural Selection. Random implies that anything can happen and nothing is predictable. But, as is, since the changes in speciation are very, very incremental, there are really only a few places each offspring can go in change at a generational level. Random is just not the right word.
I think that we're having a micro/macro disagreement--if you look at the way any one species has evolved, sure, there is a range of possible adaptations and ways the species can evolve. It's not perfectly random (e.g. equal probabilities) whether we'll grow a superflous third nipple ala Krusty or sprout wings or develop a better immune system.
But how our immune system may grow stronger is "random" in the sense that we don't have control over to what it's exposed. Say some weather phenomenon seriously alters an ecosystem...you're going to get a different evolution within that system as a result.
Random and weighted probabilities are consistent--but random is a perfectly good proxy for "influenced by uncontrollable phenomena." The key element of random is "chance," not "equal chance." I haven't heard a scientist claim that any evolution was guaranteed and not ultimately subject to some degree of chance (and hence, randomness).
