[drdeca]

I don’t see an issue with saying “X-ray photography machines, and deep-space radio telescopes, are (or at least contains-a, in the case of the telescope) cameras”. They just aren’t ordinary cameras of the sort that a typical person might take a picture with.

I think most of the reasoning you would want to do with a concept of “camera” that excludes X-ray machines and telescopes, but includes night-vision, could be handled with “portable camera”?

Hm, I guess you probably want to include security cameras though..

Ok. “Portable cameras or security cameras”.

[HelloNurse]

An universal ontology cannot have any notion of an "ordinary" camera, not because of expressive limitations but because it's subjective.

Is a CAT machine a camera? Maybe only its sensor and the computers that reconstruct images? Maybe just the sensor? It mostly depends on your location in the supply chain.

Is a box with a projection plane and no means to capture images a camera? Before about 1830, definitely (and then making photographs became a simple upgrade for your "camera obscura").

[drdeca]

I don’t think the “before 1830” case is really an issue. That’s just an example of the meaning of words changing.

I didn’t mean that “ordinary camera” should be a term in the formal ontology. I meant something more like “If you want to formalize the notion of ‘a camera’, it should include the CAT machine and telescope. If you want to address only the types of cameras that you think of as ordinary cameras, you should add extra qualifiers to get at what you mean.” .

(Where, “what you mean” might not get the term “ordinary camera”, but something more clear and descriptive.)