Pou hilos, ke pou koutali.

Differentiate the mix (hilos) that you are making - from the spoon, with which you are making it.

A philosphical saying about getting your understanding of your modes of action correct - otherwise confusion arises.

The saying reminds me of the theory of Logical Types in Whitehead and Russels philosophical work Principia Mathematica.

Also one of the phrases that begun the cybernetic revolution - "the map is not the territory."