in the midst of this world | we stroll along the roof of hell | gawking at flowers

 --- Kobayashi Issa, trans. Sam Hamill, quoted in Joel Pulliam, 45. Tokyo Cemetaries

In full

世の中は地獄の上の花見哉 (Google Translate)

in the midst of this world

we stroll along the roof of hell

gawking at flowers

Goodhart’s law: the notion that, once you start using a given measure as a target, it stops being a useful measure

 --- via Feedback, New Scientist, April 2025:

Feedback is irresistibly reminded of Goodhart’s law: the notion that, once you start using a given measure as a target, it stops being a useful measure. In this case, everyone is trying to make videos that get hundreds of millions of hits, so there are loads of videos with hundreds of millions of hits. It isn’t at all clear that any of those videos are, in any meaningful sense, good or useful. But they sure do hoover up advertising money that could otherwise be used to support popular science magazines.

From Wikipedia

Goodhart's law is an adage that has been stated as, "When a measure becomes a target, it ceases to be a good measure". It is named after British economist Charles Goodhart, who is credited with expressing the core idea of the adage in a 1975 article on monetary policy in the United Kingdom:

Any observed statistical regularity will tend to collapse once pressure is placed upon it for control purposes.

Goodhart, Charles (1975). "Problems of Monetary Management: The UK Experience". In Courakis, Anthony S. (ed.). Inflation, Depression, and Economic Policy in the West. Totowa, New Jersey: Barnes and Noble Books (published 1981). p. 116. ISBN 0-389-20144-8.

In the sublime war of man against Reality man has but one weapon, the imagination

 --- Benjamin de Casseres, according to QuoteInvestigator. Often misattributed to various people, including Lewis Carroll and Jules de Gaultier,

From an essay by Benjamin de Casseres about the English poet Percy Bysshe Shelley in The Poetry Journal, 1916:

In the sublime war of man against Reality man has but one weapon, the imagination. The ethereal imagination is the highest form of the evolution of the transfiguring and sublimating power of images. It marks the boundary line between the mystery of matter and the mystery of spirit. It is the fine volatilized plasma of an esoteric dimension, of a world where the truths hinted at by the x-ray and radium are true for the human mind and body.