In the abortion debate there is a line of argument that goes like this:
The fetus is not a moral sentient being because it doesn’t think, therefore it’s not a person and can be killed.
Such arguments are known as body/self dualism.
As you can see, those who argue this believe a human body exists, then later a “person” inhabits that body. The premise is non-sensical and needs to be shown as such.
Using that logic, how can one demand bodily rights when one doesn’t view their body as intrinsic to their person? Since the origin of their personhood is doubtful, evidence must be produced that they are in fact valid and rightful owners of said body, the body they are claiming ownership over, for how do I know I’m not dealing with a “person” who’s using a stolen body? In fact, how do I know if there’s not more than one person in that body?
Sounds foolish? Yes – but that’s what they are arguing: that human beings aren’t intrinsic. They demand we treat them as intrinsically valuable human beings, while arguing that the fetus is not.
Take the proverbial advice and never argue with a fool – because people might not know which one is which.