Dr.MarkI can give you one simple problem.
If you just move the tongue by it-self, isolated, Rowuk would be right.
I agree and that's why I'm suggesting that when we raise our tongues forward and up, this appears to have an effect on the closeness of the lips due to the tongue and the jaw being attached. The tongue can do flip-flops and it won't amount to a hill of beans if the aperture isn't the right size.
It does not effect the embouchure one bit (at least it is not noticeable), however, your embouchure changes while you talk and shape your vowels and consonant's as does the tongue to form those sounds correctly. So if the tongue is used correctly, and you allow the rest of the system (jaw, embouchure etc) to do what it would do by the movement of the tongue, then it does do something.
Isolating the tongue completely from the picture (jaw, embouchure etc) and saying "there you go does not effect embouchure" as I did, on 2nd or 3rd page when I first tried it, is incorrect way of playing in the first place, and the body does not work that way either, so that is an invalid point.
Another point I can make having been more conscious of all this since I started to look at this thread, is this:
When you 'do not move the tongue' and only go to move the embouchure etc to produce higher notes, your tongue, whether you like it or not, will move and not sit in the identical position it did on the low notes.This I noticed with myself. When I 'thought' I isolated the tongue and just moved my embouchure to achieve the notes... the tongue actually did move because everything else did.
So you can either move your embouchure and jaw and air, which will by default move your tongue, or, you can move your tongue like you do every day when you walk, to channel and shape the air, which will by default move your embouchure and jaw.
Which again comes back to the point I made near the beginning of this thread: Why only play with embouchure (which is the last phase before a sound is produced - once air leaves mouth, that is the end of controlling it) when you can control/channel it via the tongue BEFORE it leaves the mouth giving you more stability and consistency.
Great question! Because for years and even today there are people that say "faster air makes higher notes" It appears that in the process of making "faster air, the tongue is raised which has an effect on the jaw which then has an effect on the distance between the upper and lower lip.
I would like to also suggest one other point I have noticed in my practice trying no tongue for a few days and vice-verse which I believe will be helpful. Here is my finding, which regardless of what videos and hear-say you give regarding it (3rd hand information), I got my own mouth my own tongue to test this myself.
[B]Oh my! Don't think for a second that your investigation (or anybody's investigation that's done to help them understand something) as unworthy or sophomoric for it is not. I think it's great! Bravo!