The Makedonian phalanx -- why such depth?

[Giannis K. Hoplite]

There is no posibility that they wished to rotate. It is never mentioned happening either in macedonian or earlier phalanx. Each man knew his position in it,so specificly that when they formed after a battle,the losses produced "gaps" in the phalanx.
It is also impossible to rotate. You simply cannot expect a fighting man to desert his line and go back,and all the rest behind him step forward without producing a mess. The whole thing worked because the front was remaining as much unbroken as possible.
Also there was noone counting minutes till the next rotation. You can't expect all of them doing it whenever they felt tired.
Finally it's impossile to raise your sarissa horizontal while four ranks behind you and ten to your sides have theirs down. You produce a mess.
Khaire
Giannis