AbstractThis quotation from a non-technical paper by a respected classic of (bio)membrane thermodynamics (Katchalsky, 1971) was chosen as motto for it suggests the kind of fascination exerted by the abstract and rigorous treatments of thermodynamics, which provide correct descriptions of phenomena, even without knowing the details of the systems in which they take place and of the mechanisms they have. The inescapable drawback is also suggested, namely that — in spite of being correct — such results bring very few, if any, new information about the mechanisms of the processes tackled.