In modern Western society, we've seen a great emphasis placed on marriage. Lately, with all the talk surrounding the marriage equality movement, it has become a very divisive issue in the public consciousness. In engaging in the ongoing public debate, an extremely common argument made is that allowing same sex couples would lead to all sorts of things like people marrying objects or people marrying animals OR people marrying more than one person.
So the first two make absolutely no sense whatsoever, as neither objects nor animals can consent so...that is really a non-issue. Despite this whole argument being a "slippery slope" fallacy, I would like to take this opportunity to challenge our boundaries on the third.