There is a crazy story out there about a political scientist from Columbia University who is facing criminal charges for having an incestuous relationship with his daughter. The 46 year-old professor carried on a 3-year sexual relationship with her that began at the time she turned the legal drinking age. Lawyers, journalists, and other political scientsts are all wondering how such a relationship between consenting adults can be legally condemned without resorting to Natural Law ideas that are often marshaled against gay marriage. If the principle of consent is sufficient for the legality of same-sex intercourse, then why isn’t it for same-family intercourse? Some bite the bullet and admit that it is, but most want to resist this unsavory implication. Same-family sex is just too big of a camel to swallow. Conservatives are saying “I told you so” to liberals whom they warned of a slippery slope from gay marriage to incest, while liberals are either still unimpressed by this talking point or are left scratching their heads trying to figure out a way to articulate why incest is morally wrong.
But not so fast. Articulating a reason why incest is wrong is not so easy, or at least not as easy as everyone thinks it is.* A much cited psychological study asked its participants if incest was wrong, and not surprisingly, the overwhelming majority thought it was. When asked why, everyone felt compelled to give reasons; again, nothing surprising here. What was surprising is that when the reasons where shown to be faulty the participants would not surrender their belief that incest was wrong. They “knew it in their gut,” so to speak, but no one thought that was good enough. Yet while everyone thinks this is sufficient to compel the search for justifying reasons, hardly anyone thinks it is sufficient for moral knowledge.
Gregg Ten Elshof notes this in his brilliant little book I Told Me So: Self-Deception and the Christian Life, and has replicated this experiment in his classes at Biola University. His students hmmm and haw and finally defer to Scripture on the matter. The Bible says incest is wrong, and that is how we know incest is wrong. Really? Does the law of Moses really act as a source of knowledge for this belief or do we just know it in our gut? If this is the case, then most of our theories of moral action aren’t necessary to give us this truth. Having to cite the Bible or run polling results through a utilitarian calculus to get to this belief seems be “one thought too many” as Bernard Williams would say. This is the way of rationalization, and according to Tel Elshof it is one of the many ways we deceive ourselves.
*I don’t mean to imply that good reasons can’t be given that explain why incest is wrong. A natural law theory that presupposes a “thick” view of human nature is able to the job. In this view, right action is directed towards the end of human flourishing. Actions that are detrimental to the quality of our lives are immoral, and incest is a paradigm example. The good life we aim at is an objectively good state of affairs that presupposes the right ordering of human relationships. Incest is simply not part of a good life, and there is no special case where it could be. One could never perform incestuous actions in the right place and the right time with the right person. We know this in our guts because we have human guts–it is in our nature to know this, and if we do not know this our nature is not functioning properly.