This is, as it turns out, the focus of a lot of my work (both written, and photographed), so I can't hope to go into every nuance right now. But when it comes to the argument of whether or not sexually explicit images should be hidden from unfiltered public view, there are essentially two approaches to take. The first approach centers on the fact that a lot of pornography is indeed vulgar, and that's not something that people want to be exposed to, willy-nilly, without warning. I could say the exact same thing about explicit, nonfictional violence (pictures of open wounds and such), pictures of spiders, or other things, but that's a different discussion.
As a person who is no stranger to the world of explicit pornography on the internet, I actually sympathize with this approach. I think most porn sites are a bit much to handle, personally. Sometimes, I might be in the mood for it, but even then, people's specific tastes vary widely, and so the difference between "oh my god, that's so hot" and "oh my god, that's so gross" can be remarkably arbitrary, and dependent entirely on the person doing the looking. But this goes for vulgar, explicit pornography. Artistic, tasteful renditions of human sexuality are another matter entirely. There is a world of difference between a snapshot of an anonymous stranger's hairy asshole, and an artistic photograph of an attractive model's backside. I have no problem with exposure of the former being restricted or at least accompanied by a warning, but when it comes to the latter, I would find no problem plastering it all over the sides of buses, or on billboards, let alone hanging uncovered in museums and art galleries.
The other argument, which is an obnoxious one, is to pull the "think about the children" card. Obviously, modern standards dictate that children should not be exposed to sexually explicit images, and this pretty much pushes everyone into the corner when it comes to making rules about where and how sexually explicit images are allowed to be exhibited. Personally, I hold the radical opinion that exposing children to the reality of human sexual activity is a healthy thing, and that hiding it from them actually stunts their sexual growth and fosters exactly the kind of dysfunctional hangups that are prevalent (to an alarming degree) in the adult population currently. But, unfortunately, one radical's opinion doesn't hold much sway in the face of the full threat of the law.
Nevertheless, that gray area still remains. What constitutes material of a sexual nature and what does not? Is it sufficient for a person's genitalia to be exposed? Nudists would argue otherwise. Does it make a difference if a person is in a state of arousal? Does the tumescence of a man's sexual organ constitute a "sex act"? I would argue that, unlike masturbation, intercourse, and other forms of sexual contact, erotic arousal is a state of being, not a state of doing. I don't see why anyone who is prepared to view a penis in its flaccid state should have any problem viewing it in its erect state - it is simply part of the natural function of the organ.
What if the subject's not nude? Can it still be pornographic?
And then, of course, you have questions about implication. If a sex act is not explicit, can it be restricted if it is merely suggested? What about if it's only simulated? What do you do when you can't tell? If a photograph of two people having sex is not explicit, and doesn't even display either person's genitalia, is it pornographic merely because it suggests the thought of sexual intercourse? Does it matter whether the people in that photograph are actually having sex, or merely simulating it? Is there a difference?
Does this even technically count as "explicit"?
What if a photograph is taken of two people having sex, but by the way it's taken, it's not immediately obvious that those people are having sex? What if they are having sex, but you really can't tell, just from looking at the picture? Is it pornographic? What if you don't know for sure whether or not they're having sex, and you can't tell from the picture, is there any possible way you could classify it as being pornographic? And what if you do, just to be safe, then later find out you were wrong? What kind of precedent does that set for the censorship of photos upon suspicion of sexual activity, rather than direct evidence?
A subject engaged in sexual intercourse (really!).
As you see, there are a lot of difficult questions, all of which exemplify the thorny nature of the grey area. And I like to explore those questions, explore that gray area. If I can take a picture that makes someone think twice about the rules we have, and how simple we mistakenly believe the issue to be, I'll have succeeded in my mission. So many people think they've got things figured out, but they know nothing. Wisdom is not the acquisition of knowledge, but the realization that one lacks knowledge. If I can shatter their simplified, black-and-white view of the world, well then, that's the most I could ask for as an artist.
As Terry Goodkind once wrote, a true Seeker of Truth can make a king quake in his boots with the asking of a single question.