A friend of mine made a point the other day that I thought was insightful.  If matter is all that exists, and there is no free will because everything is either determined or indeterminate, then there is no real distinction between rape and consensual sex since the distinction relies on the notion of free will.  If the will is not free, then strictly speaking, no act of sex is chosen—even so called consensual sex is not chosen.  Every act of sex is chosen for us by forces that lie outside of our control.  We may think that we choose to engage in sexual activity or choose to refrain from doing so, but these are just illusions.  Prior physical processes cause us to either have the desire to engage in sex or the desire not to engage in sex.  

How, then, can the rapist be faulted if physics have determined for him to desire to engage in sex with someone for whom physics has not determined a corresponding desire?  Is it the rapist’s fault that physics have determined for him to believe that it is ok to engage in sexual acts with others, even if they do not desire it?  In a deterministic world, such beliefs and actions are determined by physics, not chosen, and thus the person who holds such beliefs and engages in such activities can hardly be blamed for doing what he has been made to do.  He can no more be blamed for his beliefs and behaviors than my car can be blamed for running out of gas. 

In a deterministic world we could still use the term “rape” to describe sexual acts in which at least one of the participants does not desire to be part of the experience, but we could not say that what makes a sexual act an act of rape is that at least one participant in the sexual act does not consent to it since consent is not possible in a deterministic world.  The degree to which we have reason to believe that consent is real, rape is evil, and rapists are morally responsible for their behavior, we have reason to believe that materialism is false. 

For any materialists out there, I would be interested in hearing your take on this.  How do you make sense of the distinction between rape and consensual sex without the concept of consent?  And if you think rape is properly defined by the issue of consent, how do you square this with your deterministic worldview that has no room for free will?