This post will be similar to my previous post on bestiality. My argument with regard to bestiality was that bestiality has no objection to it but this supposed sin is so part of society that it is hard for people to get around this problem and examine bestiality rationally. Incest is not different from the same phenomenon. Our moral system is a good example in the case of incest and bestiality as a system that enslaves our minds. Our moral system teaches us how to stay away from bestiality and incest and we blindly follow with no reasons to back it up. This is just another example for why all of morals must be abandoned if we ever wish to free our minds from tyranny, not just religious mental tyranny but even secular tyranny which represents our morals.
Incest is something which is not commonly practiced because incest is an evolutionary disadvantage. There is not enough biodiversity when family members multiply among themselves. Thus, it is not a surprise why people are innately opposed to incest. However, some people, let us call them "rednecks", are not opposed to incest. Rednecks multiply with their own family members and are okay with it. It is almost universally accepted that the rednecks are doing something wrong but why is this so? What objection can there be to incest?
We will again ignore the whole natural argument. That is the terrible argument I addressed in my previous post on bestiality. Saying that "incest is not natural therefore it is wrong", is not just a non-sequitor but it also makes no sense to how something can even be unnatural. The Bible will also not be helpful here, even if we somehow strangely respected the moral code of the Bible. Because there is plenty of incest going on in the Bible, including many heroic figures.
Someone once told me that incest is contrary to evolution because people are made in a way to reproduce with non-family members. Therefore, if people practiced incest then the human race will be damaged in the future. This is true, but that is not a reasonable objection to incest. You know what else is an evolutionary disadvantage for people? Homosexuality. If people practiced homosexuality, not only would humanity be damaged (because the population would be smaller), as with incest, they would all be dead eventually. Is such an argument against homosexuality a respectable argument? No, it is used by many opponents of anti-gay marriage who say that if people practice homosexuality then the whole world would be dead. Their argument ignores the fact that a vast number of people are straight. In the same manner such an argument against incest ignores the vast number of people who do not get involved in incestual relationships.
So the above argument is not an objection to incest. What argument remains? There is just one last argument that can be used against incest and that is that incest might produce underdeveloped people. If people reproduce with incest then they run a risk of creating subhumans. The argument goes that it is unfair for the subhumans. They had no say in the incestual relations their parents did. Their parents therefore as hurting these subhumans when they grow up into adults. This argument has one problem with it. This argument assumes that incest must always be done for the sake of reproduction. Perhaps, incest is done for fun. It is sex after all. Most people who have sex have sex for fun. Thus, perhaps most people who engage in incest only do so because they have fun with it. Remember we are trying to argue why incest, in and of itself, is wrong, not why some various forms of incest. This argument does not address the nature of incest itself and so fails to object to why incest is wrong.
With lack of all arguments that classify incest as wrong we must take the default position. Which is that incest is not wrong.