Reading this reminds me of a quote about the charge of the light brigade
C'est magnifique, mais ce n'est pas la guerre, c'est de la folie
C'est magnifique, mais ce n'est pas la guerre, c'est de la folie
"Folie" (folly) is an amorphous, uncounted quantity, like water or sand. War is a one-of-a-kind entity, like "Peltier effect." So you speak of "some water" but "the Peltier effect."
When thirsty, you could say that "I want to drink the water," but unless there was an antecedent already set up in the conversation, it would sound a bit silly.
Once you tell me that la guerre is definite and la folie amorphous, then sure, I'd know to use the articles that way. But I would never have guessed this. It seems you have to know how the nouns feel to a French speaker; you can't simply compute the right answer from the concepts.