" A publisher who writes is like a cow in a milk bar. "
- Arthur Koestler

In the given statement, Arthur Koestler employs a vivid metaphor to describe an unusual situation where a person who typically publishes or distributes the work of others also attempts to write and produce their own content. This scenario is likened to observing a cow inside a milk bar, which would be quite out of place and odd because cows are not expected to provide the primary service offered in such establishments.

Koestler's quote delves into the roles that individuals often take on within creative industries and how these roles can sometimes overlap or conflict with one another. The metaphor highlights the importance of recognizing distinct professional boundaries and the specialized skills required for different tasks. A publisher is generally focused on selecting, editing, and distributing written works, while an author's primary responsibility lies in crafting original content. When a person blurs these lines by simultaneously attempting to write as well as publish—akin to a cow trying to serve customers in a milk bar—the quality of work from both sides can suffer due to the misallocation of resources and expertise.

Arthur Koestler was a renowned Hungarian-British author, essayist, and philosopher who lived from 1905 to 1983. His diverse body of work includes novels, biographies, memoirs, and essays on literature, politics, psychology, and science. Known for his skepticism towards dogmatic ideologies and his exploration of the human mind's complexities, Koestler contributed significantly to discussions about creativity, consciousness, and scientific research during his lifetime.