Defining Pornography

The question whether something is pornography because it is intended to have a certain effect (intentionalism) or because it is used successfully to arouse oneself (utilism)–you probably know it is pornography when you see it (evocationalism or constructionism?) brings out the perennial difference between the descriptive and the evaluative use of concepts. There is always the possibility that irrespective of one’s intentions something does or does not arouse sexual lust—and then one would have to say it may have to be described as pornography although it does not function as such, or that it cannot be described as pornographical even though it happens to arouse one.
The link between the intentions of the pornographer and the arousal evoked is a practice. It is the same with art. Artists may intend to create great art but that doesn’t mean that they will, or that the audience thinks they did. But art practice keeps the two together: a set of circumstances “designed”–whether architecturally or merely conceptually–to allow an audience to take up the artistic attitude necessary –though not sufficient–for artistic merit to surface.
The pornographer adheres to certain descriptive procedures which should allow the end-user, in successful cases, to get aroused.
So ideally, i.e. in central cases, a certain measure of intending something to be arousive is met with a certain success. This would be a sensible subjectivist approach–it is clear about the rules and leaves open possible arguments regarding the application to particular cases.

Hume, David. 1985 (1757). “Of the Standard of Taste.” In Essays Moral Political and Literary, edited by Eugene F. Miller, 226–250. Indianapolis: Liberty Fund.
Wiggins, David. 1987. “A Sensible Subjectivism?” In Needs, Values, Truth: Essays in the Philosophy of Value, 185–214. Oxford: Blackwell.