Well, Maxwell himself used "demon" but it is inferred that he meant to write "daemon" as there is nothing malevolent about his imaginary creature.

> Maxwell himself used "demon" but it is inferred that he meant to write "daemon" as there is nothing malevolent about his imaginary creature.

It's the same word. There's no distinction between them. Writing "daemon" instead of "demon" is the same thing as writing "paedagogy" instead of "pedagogy".

There is no inference available to be drawn.

There is from connotation though. It's not like the example you mention which is just a case of UK vs US spellings. In both the US and UK, "demon" means an evil spirit and daemon has other meanings, either technical or relating to Greek mythology.

No, there isn't. As etymonline will tell you:

> The usual ancient Greek sense [of demon], "supernatural agent or intelligence lower than a god, ministering spirit" is attested in English from 1560s

Or as Merriam-Webster will tell you:

> demon (noun)

> variants or daemon

> (usually daemon) an attendant power or spirit: GENIUS

Maxwell used the ordinary spelling of a common word. Why would anyone assume he meant to write something strange instead of something normal?

Because the non-strange meaning was "demon" in the Judeo-Christian sense. Before UNIX, people who weren't experts in Greek mythology had never heard of any other meaning, even if it existed among scholars.

There's no question of what Maxwell meant. He is using the word in a relatively rare sense, yes. And he's spelling it exactly the way you'd expect. There is nothing out of the ordinary and therefore nothing to explain.

> people who weren't experts in Greek mythology

The word isn't really relevant to Greek mythology. It's relevant to Greek philosophy.