Training may be based on written material, but written material is not equal. This is why World Ice Theory and Theory of Relativity were both brought up in the first place. They may be both written material, but one is unscientific nonsense and the other is the accepted leading theory in how the universe actually works.
I'll look for the exact memo that advocated lowering the water rations for the Afrika Korps in the hopes the troops would get used to it ("training and acclimitisation"), but the Afrika Korps trooper was usually issued with only 2 litres of water for all needs, when the Brits were getting 3-4 litres (with most modern guides recommending 4 litres a day). Even the Bedouins averaged 3 litres and they lived in the desert all their lives.
What does it mean that training and written material is not equal? Why can one not train oneself based on books? Why couldn't the Germans have read books on desert warfare? I have no interest in reading about your take on the philosophy of science so stick to the subject.
Still waiting for your to provide a source for your claim that the Germans were instructed to drink less water in deserts.