1. Literary (Definition: characteristic of literature or scholarly writing)
I don't think this category is intended to apply to images, as the Miller test in which it is included refers to both visual depictions and written descriptions. Nevertheless, I think that you could certainly describe the writing that accompanies the images on this blog - much of it on the subject of sex - as "characteristic of scholarly writing".
2. Artistic (Definition: satisfying aesthetic requirements, showing skill or excellence in execution)
Consider Exhibit A:
Here is a photographic image containing graphic and sexually suggestive (if not outright explicit - but most communities consider erections to be "pornographic") nudity. I'd like to think that it has serious artistic value. I'm not claiming it to be the equal of the Sistine Chapel, and art is an especially nebulous concept, but I think that at its core, art is a technical craft that concerns itself with aesthetics.
What makes a photographic image "artistic", in a fundamental sense, is the care and technical proficiency with which the artist approaches the process of creating the image, and the effective aesthetic value of the result. A photographic artist (usually) must deliberately compose his shot, often with a specific theme in mind that he wants to convey in the final image. He must take care that the subject is being lighted in an appealing way, and have sufficient knowledge of how to work his equipment.
Furthermore, in portrait photography, the artist must have an understanding of how to position the model for maximum aesthetic effect. Producing a compelling and appealing image takes a lot of work and deliberate effort. If you don't believe me, then try it yourself, and compare your results to mine. I didn't just snap this picture, I spent at least an hour of constant work and movement to get it, and then more time on the computer putting the different clones together.
I don't think everybody realizes this, but photography can be very physically demanding. More so for a self-portrait artist, who is constantly running back and forth between the different sides of the camera. I was sweating by the time I finished this shoot, and my thigh is still sore today from having to suspend myself in the position of the clone second from the left. I needed to be at just the right height - not so low that I could rest on my heels, and not so high that I could sit on the stool or table beside me - and I had to take several shots to get everything right (so that it looked good enough to be in the final image).
I put all this effort into the image not because that's what it takes to create pornography. Most people (at least most guys) are very simple-minded when it comes to sex. All you gotta do is point the camera and shoot. Most guys, when they're horny, they don't care one whit about artistic value. That's why most pornography is (unfortunately, in my opinion) not very aesthetically appealing. But no, I put effort into this image because I wanted it to be artistic. And I think that if you can successfully apply the rules of artistic composition to something as dull as a bowl of fruit, then there's no reason why you can't approach human bodies, or sexual activity, in the same way.
3. Political (Definition: of, relating to, or involving the state or its government)
Consider Exhibit B:
Political prophet George Orwell once wrote, "the sexual act, successfully performed, [is] rebellion." And this is true in any sexually repressive environment - including modern democracies governed by a prevailing religious sentiment that considers sexual indulgence to be a sin. The subject of pornography, in particular, butts right up against the First Amendment and its alleged protection of free speech, and holds a unique place in American jurisprudence as a category of speech not awarded First Amendment protection primarily on account of moral sentiment.
Sex is an enormously political act, and so long as depicting it could potentially land you in jail (based on purely subjective "community standards"), then every piece of pornography is a political protest - a statement on the legitimacy of an act at best only tenuously permitted - and even then, heavily regulated into obscurity - by the state. For example, in a country where homosexual acts are illegal (as they were in the United States not too many years ago), every instance of gay porn could be considered a political statement.
But if declaring pornography intrinsically political is too easy, consider the political message I've constructed above. I dare you to propose an argument that this message would be as effective without depicting the indecent (indeed, I imagine many would call it "obscene") subject I've chosen. That's its very point! It is deliberately provocative, as political protests usually aim to be, and takes advantage of a shocking subject to draw attention to itself - again, as many protests do. But unlike so many protests that use the naked human body to attract attention, here the body is inextricably linked to the message being conveyed.
Why is it the case that if you use nudity to draw attention to a political issue, it's protected as free speech, but if you use nudity to draw attention to the political issue of nudity (or sexuality) itself (e.g., public indecency, sexual discrimination, obscenity law), it's considered beyond the pale? This is just another case where sex and nudity are considered to have different rules than everything else in the world, which justifies authorities' decision to regulate based on morality where otherwise, in a free society that respects a diversity of opinions and lifestyles, that would never fly.
4. Scientific (Definition: conforming with the principles or methods used in science)
Consider Exhibit C:
A Qualitative Observation of the Male Sexual Response and Orgasm
Primary sources of stimulation: visual, psychological, tactile
Science concerns itself with asking questions about the natural world, and then conducting experiments to acquire knowledge, in order to better understand the relationship between things, and ultimately allow us to make predictions about the natural world (and its inhabitants). A rigorous experiment would involve making a hypothesis, and testing it by collecting measurements and things of that sort that I've omitted here, but hopefully this video gets you started on the right track.
I believe the best science comes from large, statistical studies, rather than anecdotal data, and as much as I'd love to survey a larger group of people's sexual habits, I am limited to just what I have (literally) on hand. But every document of sex we have is one more data point that helps flesh out our understanding of the wide diversity of human sexuality. Recall that when Kinsey performed scientific studies on human sexual behavior, the conservative public entirely ignored the scientific value of his research, citing it as obscenity and pornography motivated by a prurient interest. But ignorance is not the way of science - in fact, it's the exact opposite.
Fans of my photography may not realize this, but I do actually have a science background. In fact, I have a degree in physics. That said, biology has never been my strong suit. I think psychology and sociology are also interesting, but dealing with the human mind is very complex, and not as mathematically pure as the more logical sciences (nothing is more illogical than the human brain!). But as far as the human body is concerned, observation can go a long way in helping those of us who are inclined toward the science of sex - sexology, if you will - to understand just how our bodies work.
For example: the mechanism of arousal, and the physiological changes that occur in the body during arousal. I think that a lot of people don't realize just how much the size of the penis can change when stimulated. I occupy an interesting position in that I've had people tell me - in all sincerity - on different occasions, both that I am tiny, and huge. It really puts things into perspective for me, and it tips me off sometimes to those people who have a very narrow band of experience in matters of human sexuality.
And then there is the orgasm, which, outside of porn (and even there, the details are often blurred by the focus on the impact of the moment) I really don't think you see that much. Call me biased, but a video like this one - not all gross with closeups of internal anatomy and ooze gushing everywhere - but simple, straightforward, matter-of-fact, seems rather interesting from a scientific perspective, and I don't see what the big deal is. I'm not saying we should all go sharing videos like this at the dinner table (although it's not out of the question for particular dinner parties), but it's something most of us do (and most of those who don't probably should more often), and of all the things we do in life, why shouldn't this be studied and experienced like everything else?
4. Educational (Definition: tending or intended to educate, instruct, or inform)
Consider Exhibit D:
Sadly, providing sex education is itself a political act in this country, but here we're concerned with the educational part more so than the political part. There are a lot of instructional guides on the internet, of the strictly textual variety, on how to put on a condom - and it's not exactly rocket science (which it really can't be, because the whole point of condoms is that even stupid people should be able to use them - although that sidesteps the even more considerable hurdle of finding a way to convince the stupid people that condoms are a good idea). But I think it could only be helpful if there were actually more visual demonstrations of people putting condoms on.
Sex education is in a dire state in this country. It's improving, thanks to the internet, among other things. But as long as the stigma against sexual speech persists, people are only going to get part of the story. That's not to say that anyone learning about sex needs to be bombarded with sexual images, but the careful placement of a few unselfconscious video tutorials here and there would go a long way in breaking through the taboo on looking at and experimenting with our bodies.
A lot of people would say that pornography is an obstacle to sex education. And there may be some truth to that. But it's not the whole story. For one thing, when people denigrate pornography, they have the unanimous habit of generalizing a whole category of speech (the sexual category) as a commercial, profit-minded industry; when in truth, that sex tape you made with your wife is as much pornography as Blonde Beach Bimbos 5. And even if porn is often a fantasy, that doesn't mean it doesn't have things to teach us. Rather than censorship (which works just about as good as abstinence, and prohibition), we should be promoting porn literacy (thanks Dr. Klein!). And the best way to get smart about porn is to watch a lot of it.
5. Documentary (Definition: presenting factual material with little or no fictional additions)
Consider Exhibit E:
While somewhat less provocative than the rest of the evidence in this post, I'm including this image because it was well and truly unstaged. I thought about staging a recreation of any number of various aspects of my life, which not a few of my photographs already do (e.g., depicting me as a nudist in everyday situations, or engaged in the kind of erotic activities I normally do even when the camera's not pointing at me). But then this perfect opportunity came up, completely outside of my control.
I was exhausted after the photoshoot for Exhibit A above, and I collapsed onto the bed to get some rest. I hadn't taken my camera down yet, so it was still in position, aimed at the very bed I was lying on. My roommate happened to come in at just that moment, and, seizing the opportunity (something I wish she would do more often, but she's not as photographically inclined as I am), she pressed the shutter release on the camera and took this picture. I think you can tell, just by looking at it, that it has a different feel to most of my photography, which is one of the unfortunate limitations on self-portrait photography - it's exceptionally hard to take a picture of one's self without anticipating it.
I must admit, I'm a little puzzled about Google's inclusion of the "documentary" category in their list of exceptions, since, the way I see it, every photograph is a document of something. And who gets to decide what's worthy of being documented? Does it have to be about a famous person? Then what about celebrity sex tapes? Do the raunchy scenes edited out of reality television shows count as porn with documentary value? What about the proliferation of amateur porn on the internet? These are documents of what people are doing sexually, that could easily be exploited (similar to what Kinsey did) for scientific value.
I watched a documentary on prostitution once, that contained a few isolated scenes that were sexually explicit, and people were still complaining that those scenes weren't "necessary" to show the lives of prostitutes. Like, as if that's not completely missing the point of the documentary! Seems to me that's the perfect instance of sexually explicit material (which was clearly not shot with the intention of getting people off) with documentary value. If you can't even show sex when you're depicting the lives of prostitutes, then you've really gone off the deep end!
Still, I'd like to know what Google's idea of "documentary porn" is, because right now, the only thing I can think of that excludes blurry snapshot "documents" of guys' half erect dicks (and is that really what Google had in mind to permit?) is an arbitrary value judgment. I'll refrain from making any further comments until I do.