Human Dignity and Bioethics

Dignity and Bioethics | 491
universally, clashing with our most deeply held moral views. One is
therefore led, by a process of elimination, to accept that dignity is the
worth all human beings have simply by being human.
On the basis of all that I have explained about dignity thus far,
it follows that if a human embryo is a member of the human natural
kind, then it has all the intrinsic dignity of the human natural kind.
And if that is true, then it cannot be killed, even to do good for others,
without violating the fundamental moral duties that flow from
recognizing intrinsic dignity. Thus, the fundamental question with
respect to whether a human embryo has intrinsic dignity is whether
that embryo is an individual member of the human natural kind.
What else is a human embryo, however, but an individual member
of the human natural kind at the earliest stages of its development?
This is what a human embryo is, biologically and ontologically. It is
not a different kind of thing (say a slug or a porpoise). It is what every
human being is (or was) at 0-28 days of development.
Judith Thompson has argued that “a fetus is no more a human
being than an acorn is an oak tree.” 34 Thompson is precisely correct
in her analogy, but precisely wrong in the biological, ontological, and
moral conclusions she draws from it. Despite her rhetorical fervor,
Thompson has it backwards. A fetus (or an embryo) is a member of
the human natural kind at the earliest stages of development, just
as an acorn is a member of the oak tree natural kind at the earliest
stages of its development. Every human being’s history can be traced
back, as a continuous existent, to its own embryonic stage. Every oak
tree’s history can be traced back, as a continuous existent, to its own
acorn stage. 35 In fact, the continuity is clearer in the case of human
development. The concept of natural kinds has been introduced into
philosophy to do just this: to account for the continuity and change
of individuals over time. “Embryo” and “acorn” are not terms used
to sort different natural kinds. Rather, these words are used to distinguish
phases within the development of two distinct biological natural
kinds. “Embryo” is a phase-sortal term for animals and “acorn” is
a phase-sortal term for oaks. 36 If intrinsic value inheres in individuals
as members of kinds, then it inheres in them throughout their natural
histories as members of that kind undergoing the development
that typifies the kind. Thus the intrinsic dignity of the human inheres
in embryonic members of the human natural kind every bit as much