Definition of Evolution

Can we drop the 'living systems' and stick with 'populations'? What I'd like to know then is what do we call the 'unobservable changes in populations that occur outside an observed time frame'? No - mechanisms should be the realm of theories. Events should just be described as they happen and we should develop theories to explain them as best we can. Consider it acknowledged. I'm not sure why you needed that - I thought it was obvious!

If evolution is change in populations over time - observability of this phenomenon doesn't change the phenomenon so why should we give it a different name?I understand you argument is that we cannot be sure of events that happened before direct observation - but that should have no bearing on the name we give something - otherwise you'd have to call Creation 'fantasy' since that was also inherently unobservable.This doesn't really make much sense - why not stick to one word to describe one phenomenon?

It isn't in the definition of evolution. You are thinking of natural history not evolution. Evolution is a different thing. Right - so fantasy is a pretty useless term in a definition, then. Well - that would make a lot of historical science speculative - but that is hardly a bad thing. This includes all creation stories - moreso in fact. As would I -where common descent means from a universal ancestor of some kind. That should not be in the definition of evolution as a broad term that the theory of evolution explains. Common descent should be limited to discussions on evolutionary history of life on earth. That's a different thing to just 'evolution' though.

The problem with this position is that it must be applied to all definitions and it is unnecessary. If the allele's of a population change, it is evolution. If they haven't changed - it isn't. It would be like saying murder is unlawful killing that evidence demonstrates occurred. It isn't - murder is any unlawful killing (I appreciate there are other conditions depending on the legal system, but none of them change the point I'm making). Whether we can say a murder has happened in any given case depends on the evidence.Likewise, whether evolution happened in any given case depends on the evidence.One must be open minded, and this how being open minded works (since I am sure you consider yourself to be so, I doubt you will argue this):
Assume natural history as described by scientific consensus happened - what would we call the process that generated this history? We would call it evolution.The question of whether natural history happened the way they say it did or not is irrelevant to the name we would give the process that led to it if it did. The definition of evolution make no inferences whatsoever. The definition of evolution does not infer natural history in any way shape or form. The definition of evolution does not even infer that it happens at all and nor should it. The definition merely states that if a change in allele frequency happens, then biological evolution has occurred.

It is the crux of the EvC argument it shouldn't be anything to do with the definition of Evolution though. Does the definition of evolution that was put forward infer this though? Naturally, if you say evolution to a layman he'll think of natural history, but changing the definition won't change that. We'd have to alter natural history to do that - which is an entirely different proposition.However, the definition: 'Evolution is the change in hereditary traits within populations of species over time', makes no inference. Can you show me different?

Yes - it is acceptable. There are other acceptable definitions such as 'Evolution is the change in hereditary traits within populations of species over time'. Futuyuma wonderfully put it like this 'Biological evolution ... is change in the properties of populations of organisms that transcend the lifetime of a single individual...The changes in populations that are considered evolutionary are those that are inheritable via the genetic material from one generation to the next.'Curtis and Barnes' "Biology" gives us "evolution can be precisely defined as any change in the frequency of alleles within a gene pool from one generation to the next.""Larry Moran has collated these quotes in this rather famous article - and he has recently expanded on this article at his blog. In which he tackles some of the issues that have arisen in this thread:

quote:

---

Many people are confused about the difference between a definition and an explanation. That's why we often see incorrect "definitions" that describe how natural selection works. This is wrong. In order to be useful, a definition has to enable us to distinguish examples of evolution from non-evolution but the definition should be neutral with respect to how evolution occurs. It should not distinguish, for example, between Lamarckian evolution and Darwinian evolution even though we know that one of these explanations is incorrect.

---

He also warns us of confusing the scientific term of biological evolution with the modern vernacular definition. The latter is of little interest to us here! He concludes with

quote:

---

The amazing thing about the minimal definition of biological evolution is that it doesn't carry any baggage concerning the history of life or its future. As soon as we try to define evolution in terms of the historical record, we run into all kinds of problems because we confuse evolution as a process with evolution as a history of life.

---

To be honest - I think that should conclude things nicely, no?