Libertarians argue that individuals have rights but disagree over whether rights are inherent or acquired. As I have argued elsewhere, the theory of acquired rights is not logically defensible. Only the theory of inherent rights provides libertarianism with a coherent rights theory. However, this is not the majority view among libertarians, many of whom apparently cannot believe the implications of the theory of inherent rights.
The claim that a human embryo or fetus has rights seems to be astoundingly counter-intuitive to many libertarians. Some libertarians find this idea so unimaginable that they forget to actually make an argument and merely state their own incredulity as their refutation. The result is that one of the most common objections to the theory of inherent rights made by libertarians is the argument from incredulity. This article provides some examples.
Benjamin Tucker thought that children do not have rights because they are the property of their parents. He seemed to think it persuasive that if this were not the case then a pregnant woman could not commit suicide at will:
Certainly the mother’s title to the child while it remains in her womb will not be denied by any Anarchist. To deny this would be to deny the right of the mother to commit suicide during pregnancy, and I never knew an Anarchist to deny the right of suicide.
Walter Block made almost exactly the same argument. He considers the very idea that a pregnant woman may not ethically commit suicide so preposterous as to make his case with it:
Consider the case where the mother dies while pregnant, through suicide. Wisniewski would have to consider her a murderer as well, since she had invited in the fetus, and now leaves it in the lurch, unjustifiably killing it, too. In contrast, I am not logically forced into that conclusion.
Elsewhere, Block reiterates his disbelief that anyone could hold such an argument:
no one else would make this sort of legal judgment. More important, it is simply incorrect to regard the pregnant woman who commits suicide as a murderer
Neither Tucker nor Block could conceive that there are circumstances under which it is immoral for a parent to immediately kill themselves. One wonders if they would also be incredulous of anyone who thinks that it is immoral for someone driving a vehicle at high speed on a busy street to shoot himself at the wheel, or for the pilot of a passenger aircraft to commit suicide mid flight. Would they argue that the rights of the driver and the pilot to immediate suicide override the rights of innocent bystanders not to be killed by their actions?
Wendy McElroy demonstrated her incredulity when she pointed to the implications of inherent rights for pregnant mothers who want to take drugs or go parachute jumping:
if you admit the idea that the fetus is a human being for whom the woman is legally responsible, then the woman cannot take any action to imperil the life and well-being of the fetus. Almost everything she puts into her system is automatically introduced into the system of the fetus and, if the substance is harmful, it constitutes assault upon the fetus on the same level as strapping me down and forcing drugs into my body. Moreover, life-endangering acts, such as parachute jumping, would place the unconsenting fetus in unreasonable danger. If the woman has no right to kill the fetus, she can have no right to jeopardize its life and well-being.
Amazing though it seems to McElroy, yes, the principle of parental obligations combined with the inherent rights of children implies that it is not ethical to take heroin or go BASE jumping as a pregnant woman. McElroy provided another argument from incredulity at the idea that certain types of birth control may not be morally legitimate:
Since an individual with full human rights is said to exist at the moment of fertilization and since IUDs work by disrupting fertilized eggs, women who use these devices must be guilty of attempted murder, if not murder itself. Other forms of birth control which work not by preventing fertilization but by destroying the zygote would be murder weapons and doctors who supplied them would be accessories. As absurd as this sounds, it is the logical implication of considering a zygote to be a human being.
What exactly does McElroy find absurd? Some forms of birth control work by killing unborn children and other forms work by preventing pregnancy. If unborn children have rights, then those forms of birth control that work by killing unborn children are not morally defensible. Although she does not accept this argument, I don't think McElroy could say that the argument is logically absurd. Perhaps what she finds absurd is the enormity of the implications if she were to accept the theory as valid. This is to deny an argument on the basis that it cannot possibly be true because if it were, then the implications would be shocking. That itself is another form of the argument from incredulity.
Stephan Kinsella provided a very succinct argument from incredulity regarding inherent rights:
it seems obvious to me that a one-day old zygote has no rights yet, even though it is a potential human person, and biologically a “human life.” It also seems obvious to me that infants have rights, so that infanticide is murder.
He made a similar argument back in the 1990s, where he simply assumes the conclusion:
In the case of abortion we know the endpoints: zygotes have no rights; adult humans do. Somewhere in between we develop rights.
Conclusion
Since the argument from incredulity is a logical fallacy, it is self-refuting. It is remarkably fatuous of libertarians to resort to this argument. Edward Feser's comments on the shallowness of the argument are well made:
Appealing, as is often done, to what a fetus, embryo, or zygote “looks like” is unhelpful, and even philosophically frivolous: one might claim that a table “doesn’t look like” a collection of atoms swirling about, but that’s what a table is. And in fact, a table does look like that: that is exactly what a collection of atoms swirling about looks like when it is in the form of a table. Similarly, to the charge that a fetus, at whatever stage of development, “doesn’t look like” a person or a human being, one ought to reply, “Of course it does; that’s exactly what a human being or a person looks like at one month (or one week, or whatever) of development.”