A huge obscenity trial just went through in the U.K., which put the decades old Obscene Publications Act to the test. I'm happy to report that the good guys won, and the court ruled that it is legal to advertise/sell pornography depicting legal sex acts (fisting, water sports, etc.) to informed, consenting adults. Although it should have been a foregone conclusion, this is a very exciting and positive result, because in this world, you don't get to wield your basic human rights until after they've been successfully defended in court (and then, only until a different judge overturns that decision).
In addressing this result, blogger Belle de Jour writes a fantastic post that is nearly flawless, but for a small oversight that most people would probably forgive or ignore, if not outright defend, because it relates to bestiality. Yeah, I know, bestiality is different because it relates to animals and not people. Well, fisting and water sports are unpopular to a certain demographic, too. I'm not interested in animal sex and I don't generally support it (nor necessarily think that it's unproblematic to the extent that fisting or water sports is between consenting adults) (incidentally, Belle, I regret that I have to make this disclaimer, but you know, does your argument apply to fetishes that could cost you a webhost?), but what I am interested in is being consistent, even where it means taking an unpopular stance, and that's where Belle briefly (only briefly) stumbles.
The importance of consent is crucial to the smooth running of a healthy, sex-positive world. However, in order to respect consent, we have to understand it. Belle said that sex with animals is "necessarily non-consensual". It is my understanding that engaging in sex acts with animals is illegal. It may be true that gauging an animals' consent is effectively impossible, and for this reason, the ease with which a person could take advantage of and sexually abuse an animal justifies across the board restrictions against bestiality. However, to say that sex with animals is necessarily non-consensual is not accurate. If the only thing that mattered in negotiating sex were the consent of the participants, then we'd have to allow those consensual acts that we find distasteful. A person could make the argument that nobody could properly consent to fisting, or any other kind of sexual depravity, but what really counts is what the person engaging in it wants. If it's impossible for us to know what an animal wants, or if it's our collective belief that animals are too vulnerable to abuse to allow any humans to have sex with them, then so be it. But unless you're willing to ask the animals (and are able to understand them), you can't say there is necessarily a lack of consent. That's speaking for another demographic - a demographic that doesn't have a voice. If we can't understand animals, then the most we can say is that we don't know what they want (and maybe it's best not to test the waters just to be on the safe side), but that's different than speaking for them and saying "they could never want this".
It's easy to talk about sex acts between consenting adult humans, because we're currently in a zeitgeist where that sort of thing is on the vanguard of what's popularly allowed in the sexual landscape. But if we're more concerned with truth than politics, and wish to be consistent in our beliefs and ideologies, then we must be willing to extend the principles we apply to the popular issues (fisting porn, water sports, etc.) to the unpopular issues also. Otherwise we risk engaging in hypocrisy, and allowing our well-reasoned arguments to stand as nothing more than convenient explanations for why we ought to be doing what it is we want to be doing. That's not science, it's rhetoric. And I must ask the question, is "consent" a privilege we extend only to those whom we deem fit for it (in today's zeitgest, living adult humans), like as if it were the right to vote, or the right to own land, or is it something we ought to extend to anyone (my own personal prejudice is toward living organisms, with the caveat that dead or inanimate objects don't have much to lose by being "inappropriately" handled - when was the last time you asked your vibrator for consent?) who can demonstrate that they have a personal will and the ability to differentiate (and communicate, on some level) between something they want or enjoy, and something they do not?