A Critique of Block on Abortion and Child Abandonment (Walter Block) (Essay‪)‬

According to Block's theory of "evictionism" (1977, 1978), a fetus can be aborted only if it is not killed as a result (provided that it is a genuine medical possibility). Block claims to derive such a conclusion from the libertarian axiom of non-aggression, which prohibits harming other human beings (even those not [yet] conscious of their humanity), but allows for forcible removal of trespassers from one's private property (in this case the woman's womb). Further, he denies that the voluntariness of the pregnancy obliges the woman to carry the fetus to term; such an obligation could stem only from there being an implicit contract between the two, and Block denies the existence of any such contract on the ground that one cannot consent (even implicitly) to any decision made before one came into being. Thus, he contends that the only valid reason for obliging the mother to carry out the pregnancy could stem from the existence of a relevant positive right (e.g., fetus's right to life), which is a notion incompatible with libertarian ethics. And yet, curiously enough, as indicated in the first paragraph, he also asserts that lethally aborting the fetus counts as a murder only given the existence of non-lethal ways of performing abortion, but does not so count if no such methods are available. this in itself seems to me to undermine Block's proposal, since it appears to introduce an arbitrary complication into the principle of non-aggression--after all, if evicting a trespasser is a right of every human being, and one should not be thought of as responsible for what happens to the trespasser after he is evicted, then why should the moral evaluation of the act of eviction depend on what eviction options are available and on which of them is applied to the trespasser?