Dr Adequate writes:
Ok then, give me an example of such direction. Say a feather was floating south for a minute, a gust of wind blew it north, then the wind changed and carried it south-east. What was the direction the wind was speeding it up in?
When the direction of the feather changed from south to north, it was accelerated in a northerly direction. When it then went southeast it was being accelerated southeast (feathers have a high area/mass ratio, so I'm discounting its momentum).
It seems unless you know where you want the feather to go, you can hardly talk about whether the feather was slowed down or sped up in any particular direction at any turn of the wind.
It is actually possible to determine the position, speed, and acceleration of objects without knowing where I want them to go. This is a shame, otherwise I should have a unique and lucrative job.
The word's definition is directional change. You think it's a good term for that? I don't know. Especially in the singular. When there are so many directions. Change and transformation of species might be better. Even in the title it says origins and not evolution. He used it sometimes but not overwhelmingly like it is used now.
I really don't see the problem. But if there is one, it's probably too late to change the English language now.
That is all true what you say about measuring the motion of isolated objects. I reckon that your analogy breaks on closer examination though. Your missed my initial point already because as a breeder you are the first to define what the object in motion is, let alone the direction. Consider it for example growth of a tree. The trunk and crown if taken as a whole may be assumed to move sunwards, yet it is going wider at the same time, branches are growing in all directions, the vectors of that growth are not quite parallel, each leaf is getting wider too.
What is the direction of the growth of a leaf? Even if you roughly define that somehow, the same leaf could be still divided into smaller parts that are growing and you can to consider the direction of each and every part and those directions are far too many again and the closer you look the more complicated it will get since smaller parts instead of just growing may be dividing and getting replaced.
Then if your consider more than one season, the leaves themselves may be falling and new ones appearing to replace them in spring and so on. The directions are way too many to start talking about the rate of acceleration without first isolating some that you might desire to measure.
To talk about a particular direction you need to isolate a particular segment of that growth or consider the tree as a whole, otherwise the vectors may remain ill-defined. The direction of motion of changing life is more like the growth of that tree than the motion of a feather on the wind.