dietary decision in a macromutational shift of content, but with no genealogical
break in continuity, from ten previous generations of strict observers of kashrut.
The objections that most of us would raise to Hull's interesting proposition
include both intellectual and moral components. Certain kinds of systems are, and
should be, defined purely by genealogy and not at all by content. I am my father's
son no matter how we interact. But such genealogical definitions, as validated by
historical continuity, simply cannot adequately characterize a broad range of
human groupings properly designated by similarity in content. When Cain mocked
God's inquiry about Abel's whereabouts by exclaiming "Am I my brother's keeper"
(Genesis 4:9), he illustrated the appropriateness of either genealogy by historical
connection or fealty by moral responsibility as the proper criterion for
"brotherhood" in different kinds of categories. Cain could not deny his
genealogical status as brother in one sense, but he derided a conceptual meaning,
generally accorded higher moral worth as a consequence of choice rather than
necessity of birth, in disclaiming any responsibility as keeper. As a sign that we
have generally privileged the conceptual meaning, and that Cain's story still haunts
us, we need only remember Claudius's lament that his murder of his own brother
(and Hamlet's father) "hath the primal eldest curse upon't."
Ordinary language, elementary logic, and a general sense of fairness all
combine to favor such preeminence for a strong component of conceptual
continuity in maintaining a name or label for a theory. Thus, if I wish to call
myself a Darwinian in any just or generally accepted sense of such a claim, I do
not qualify merely by documenting my residence within an unbroken lineage of
teachers and students who have transmitted a set of changing ideas organized
around a common core, and who have continued to study, augment and improve
the theory that bears such a longstanding and honorable label. I must also
understand the content of this label myself, and I must agree with a set of basic
precepts defining the broad ideas of a view of natural reality that I have freely
chosen to embrace as my own. In calling myself a Darwinian I accept these
minimal obligations (from which I remain always and entirely free to extract
myself should my opinions or judgments change); but I do not become a
Darwinian by the mere default of accidental location within a familial or
educational lineage.
Thus, if we agree that a purely historical, entirely content-free definition of
allegiance to a theory represents "too little" commitment to qualify, and that we
must buttress any genealogical criterion with a formal, logical, or anatomical
definition framed in terms of a theory's intellectual content, then what kind or level
of agreement shall we require as a criterion of allegiance for inclusion? We now
must face the opposite side of Goldilocks's dilemma—for once we advocate
criteria of content, we do not wish to impose such stringency and uniformity that
membership becomes more like a sworn obedience to an unchanging religious
creed than a freely chosen decision based on personal judgment and perception of
intellectual merits. My allegiance to Dar-
10 THE STRUCTURE OF EVOLUTIONARY THEORY