mijopaalmc
Philosopher
- Joined
- Mar 10, 2007
- Messages
- 7,172
http://www.simonyi.ox.ac.uk/dawkins/FAQs.shtml
I have sought, without success from a number of scientific authorities an answer to the following question, viz. how does the environment influence the gene, e.g. the development of the giraffe's long neck. Random mutations are not fully explanatory.
Perhaps you would be good enough to suggest a hypothesis or perhaps direct me towards further reading.
letter from P. Dawnay
Dawkins response:
You rightly say that random mutation is NOT a good explanation for the evolution of giraffes' necks or, indeed, of anything else! Fortunately, nobody has ever suggested that it IS a good explanation. The correct explanation -- and it is indeed an excellently satisfying one -- is Darwinian natural selection. Darwinian natural selection is emphatically NOT the same thing as random mutation. Although random mutation does play a role in the theory, natural selection itself is the most important ingredient, and natural selection is the exact OPPOSITE of random.
Three of my books, The Blind Watchmaker, River Out of Eden, and Climbing Mount Improbable, are devoted to explaining how Darwinian natural selection works, and why it is such a satisfying explanation.
As mentioned before, my science dictionary defines random as being unrelated to past or future events. It also says that it refers to all possibilities being equally likely. Evolution is wholly dependent on past events--mutations are relatively random--what survives to reproduce is not.
If that does not answer Mijo's question, then I suggest that nothing can.
I would suggest that you are deliberately using a definition of "random" that allows you to ignore the probabilistic processes of evolution. Evolution is by definition a non-trivial stochastic process because it is based on probabilities of individuals' passing on their genes to the next generation in greater proportions to other individuals. Now, I fully admit that if it can be determined all the individuals who pass on their genes to the next generation in greater proportions to other individuals differ in a distinguishable way (i.e., by a specific genetic polymorphism or set thereof) then the process of natural selection is deterministic, because identical individuals are selected in identical ways. If, however, it can be determined some the individuals who pass on their genes to the next generation in greater proportions to other individuals are indistinguishable for others who don't, barring a catastrophe that no individual would survive no matter how fit it was, then the process of natural selection is stochastic, because identical individuals are selected in different ways.
At our current state of knowledge it appears that the latter situation is most likely the case. However, this assessment, as Ichneumowasp has wisely pointed out, could be due to our incomplete knowledge of the genetic compositions of the the individuals who pass on their genes in greater proportions to other individuals and the individuals who don't. I just don't see what the problem is with saying some like I just said above. First, we would acknowledge that the appearance of stochasticity of evolution at the generational level may be because of our incomplete knowledge of just how many genes and polymorphisms thereof effect the fact of whether an individual passes on its genes to the next generation in greater proportions to other individuals and then we would provide for the fact that if identical individuals are selected identically evolution is deterministic whereas if identical individuals are selected non-identically evolution is stochastic.
It may not be the simplest explanation, but it avoids the ambiguities of calling evolution "non-random" or "random".