Originally Posted by Vis
The mammals from which the monkeys evolved also had tails. The precursors to mammals had tails.
Nothing triggers the mutations for a purpose. It's entirely random. Mutations that have no use or are detrimental, don't survive. Those that help are naturally selected.
Evolutionary change is stuck with the prior structures. It can never go back to the drawing board. Consider recurrent laryngeal nerve in mammals. It takes a very circuitous course, looping from the brain stem down around the aorta and then back up to the larynx.
OK, the example you offer makes perfect sense especially where you state: "natural selection couldn’t manage that, for severing and rejoining a nerve is a step that reduces fitness"
So let's look at it from another perspective.
On the subject of tails, it is said that we all once had tails (the coccyx being the artifact) but what caused us to lose our tail?
There must have been some causative moment at which our tail began to recede and there must have also been some evolutionary time frame and skeletal example of that receding tail, but where is it and how long did it take to recede to its current state?
I find the nano-molecular theory fascinating and I wonder if there may actually be a connection between wishing for something (either consciously or unconsciously) and then having it become reality over an evolutionary time scale.
If I'm understanding that theory correctly, it seems to state that molecules on a nano level can join in what can only be described as a purposeful configuration, sharing similar movement and eventually affecting a change in development favoring such movement and there also seems to exist an undeniable relation to Quantum Entanglement.
Since Quantum Entanglement has been included in theoretical explanations of human consciousness, it may be too that some form of cognitive influence concerning evolutionary mutation could also exist and perhaps such mutations might not be completely random after all.
I love stuff like this!