Darwin & the Declaration 2

In the Declaration of Independence, the Continental Congress appeals to the “Laws of Nature and of Nature’s God”.  Is a doctrine of natural law and natural rights compatible with a Darwinian account of the evolution of human beings? 

The most common argument to the contrary can be found, eloquently and intelligently presented, in S. Adam Seagrave’s “Darwin and the Declaration” [Politics and the Life Sciences, Spring 2011]. 

The proposition ‘‘all human beings equally possess certain basic rights,’’ or the distilled Declaration, necessarily assumes two important points: 1) that there is a group of beings called ‘‘human’’ whose members are specifically different from other organic beings; and 2) that each individual within this specific group of beings equally possesses things we call ‘‘basic’’ or ‘‘human rights.’’

By contrast: 

Taking Darwin’s arguments bearing on the specific differences defining human beings in the Descent and the Origin together, the steps of this argument may be represented as follows: 1) specific differences in general are vaguely and arbitrarily defined, since they actually differ only in amount or quantity from mere individual differences; 2) the entirety of organic nature presents an ‘‘insensible’’ or continuous series rather than a discrete one, since all differences between individual organic beings are in principle commensurable; and, 3) human beings are not exempt from this situation.

According to Seagrave, the doctrine in the Declaration requires an essentialist theory of species.  Every species is defined by a specific set of traits such that every member of the species has that set of traits and every individual who has that set of traits is a member of that species.  From the traits that define the human species, one can derive natural rights. 

In Darwin’s view, the species are distinguished only in matters of degree (some are bigger, some more intelligent, etc.)  So one species differs from another as the set of numbers from 13 to 50 differ from 45 to 76.  The distinctions between species are largely arbitrary, so there can be no essential natural rights belonging to such a messy smear of organisms. 

Darwin has been dead for 135 years, but let us assume that this is his view (I agree that it is) and that it represents the current state of Darwinian theory (it does not).  Is it true that there can be no specifically human rights if human beings differ from other animals only in degree?  No. 

Consider two rights: the right to vote and the right to drive.  Suppose that intelligence is a measurable factor and that we can place all mammalian brains on a scale from one to one hundred.  Suppose, moreover, that we determine that the capacity to make a choice and vote accordingly requires an intelligence of 67 or above.  Is it not obvious that all human beings would be above the line and all non-human organisms far below it?  The mental capacity required to participate in the franchise is like one of those height lines at the entrance to a Disneyland ride: you either get to ride or you don’t.  Taller people don’t get any advantage.  Animals don’t get on.  Likewise, being a stunt driver doesn’t get you more rights to drive than the average Joe.  Differences in degree could be the basis for specifically human rights even if that is all we have. 

The essentialist account of species has been rejected by modern biology because the latter wants a definition that covers all species great and small.  The if traits Y then species A just doesn’t work in a lot of cases of mammals, let alone plants and bacteria.  Wolves can mate with coyote; one species or two?  Horses and Donkeys can have sons but not grandsons.  Human beings qualify as species under all basic definitions: we breed only with each other and we represent the sole surviving branch on the hominin tree.  No one doubts that this is a real distinction. 

Just because the essentialist account of species doesn’t work with most species doesn’t mean that it never works.  Let us define a species by the following traits: it is a mammal and it is capable of powered flight.  That describes bats and only bats.  Let us define a species this way: one member can draw a stick figure on a white board with five lines and a circle.  A group of conspecifics can recognize that the figure indicates one of them.  That describes human beings and only human beings.  I suggest that what I just demonstrated is the power of logos.  All undamaged sons and daughters of sons and daughters have it. 

Let’s try another.  One animal watches two others.  One of the observed helps the other and the other refuses to return the favor.  The observer is offended.  I can’t be certain, but I expect that this is something all human beings and only human beings are capable of.  We are capable of conscious, deliberate, moral responsibility.  It is in that capacity that the rights mentioned in the Declaration are grounded. 

Aristotle advised us that we can’t expect the same precision in moral reasoning that we can expect in mathematics.  That doesn’t mean we can’t make rational moral judgments.  Biology is messy, but not incoherent.  Human beings are more than animals.  We are, however, at least animals.  There is the direction political theory most face.