Quixotic:
having or showing ideas that are different and unusual but not practical or likely to succeed:
This is a vast, exciting and some say quixotic project. [Cambridge Dictionary]
Sometimes, it’s just nice to know a definition more precisely, and, yes, I’ve read, in translation, The Ingenious Gentleman Don Quixote of La Mancha, which I found tiresome, but I have a low boredom threshold.
Noted in “To fix the world’s problems, we need both optimism and pessimism,” NewScientist (14 December 2024):
Going into a new year with such uncertainty, it is hard not to feel pessimistic, but that might not be a bad thing. Next year will mark 10 years since the Paris Agreement came into force, and even at the time, it was clear the 1.5°C target was pushing at the limit of what was achievable. As we wrote in our end of year leader at the time: “As a call to action, it is quixotic: its aspiration of a 1.5°C cap on global warming seems almost totally unachievable.” Indeed, remaking the modern world to halt greenhouse gas emissions and reach net zero is the most ambitious goal humanity has ever set itself.