The Spanish Socialist Workers’ Party (“PSOE”) has apparently signed on to the agenda of the “Great Ape Project” – namely, to establish legal and moral standing for most species of apes by virtue of what the Project perceives as their sufficient mental capacity for moral personhood. To my knowledge, this is the first time an organized political party of any consequence (including the Greens) has taken this stance.

The Spanish Socialist Party will introduce a bill in the Congress of Deputies calling for “the immediate inclusion of (simians) in the category of persons, and that they be given the moral and legal protection that currently are only enjoyed by human beings.” The PSOE’s justification is that humans share 98.4% of our genes with chimpanzees, 97.7% with gorillas, and 96.4% with orangutans.

Note that the citation of genetic closeness is both a somewhat contentious issue and not directly morally relevant. The Great Ape Project itself refers to mental capacity, not genetic consanguinity. This is still an interesting development, however.

The measurement of genetic differences between species is more complicated than it looks, and the interpretation of those measurements is extremely contentious. For one thing, it matters a great deal whether you compare the entire genomes of the species, including the heterochromatin (non-transcribed “junk” DNA), or only the euchromatin (functional DNA) that produces selectable traits. Junk DNA is open to random mutation, since changes in its structure do not result in changes in biolgical functions; differences between species in these segments of chromosomes thus tend to accumulate steadily (this fact provides a convenient “clock” by which the dates of evolutionary events can be estimated). Functional DNA mutates at lesser rates, because significant changes in functional genes are often fatal or maladaptive, and thus eliminated from the gene pool; the exact rate at which a given gene changes depends upon the chemical and functional specifics of that gene and its resultant protein, and is distinctive for each gene. Thus, comparisons of the entire genome include comparisons of the highly divergent, randomly-mutating heterochromatin as well as the less-divergent, highly conserved euchromatin, and thus show larger degrees of difference; comparisons of functional genes only show closer connection. (The now-standard “98%” figure was based on comparisons of particular genes, not even large sections of the genome; since those genes included ones for vital biochemical functions, and hence tend to be highly “conserved” – unchanged by evolution – they give systematically higher figures for similarity.) Today, also, it is known that there are significant differences between human and ape genomes in terms of sequence repetitions, bacterial and viral gene inclusions, and some structural sequences, in addition to just correlations between base pair sequences. So the percentage figure you get depends largely on what you are comparing, and to some extent a percentage similarity is not even an applicable concept.

Understanding what those differences or similarities mean, however, is an even harder task. For one thing, the differences are far from random: the human genome shows a distinctly higher degree of sequence repetition (i.e., the creation of new genes, available for further evolution, by duplication of old ones) and faster evolutionary rates in genes related to brain structure, when compared to other primates – the evolutionary significance of this is obvious. So it may be that whatever degree of difference there is between the genomes in percentage terms, what matters more is which genes are different. From another perspective, it may not matter much at all what the percentage difference is between various genomes. Multiple comparative studies clearly show largely unambiguous evolutionary lineages; whether the difference in gene sequences between humans and chimps is 1%, or 2%, or 5%, or 20% is irrelevant – there is no question that the two species of chimps are our closest living relatives, followed by gorillas, then orangs, and so forth. If 2% is the difference between humans and chimps, then a 2% change in DNA is what it takes to distinguish between a human and a chimp – if 20%, then 20%. The relationship does not change, whatever the figure might be. Finally, none of this – whether the number turns out to be large or small – makes a difference to the question whether apes deserve moral status comparable to that of humans. To cite these figures as evidence for such a claim is no more than a familiar example of the “naturalistic fallacy” (the claim that some certain natural fact implies a moral conclusion all by itself). To their credit, the Great Ape Project people for the most part have not fallen into that trap, though this news report appears to suggest that the Spanish Socialists have done so.

All that aside, however, as a development on the political and moral landscape, this is interesting. The PSOE currently holds 43% of the Spanish National Assembly, 39% of the Senate seats, and the Presidency; if they’re serious about this policy, they stand a good chance of pushing it through. (Frankly, it boggles the mind to imagine that a major European political party is going to go to the mats on this issue, but who knows? It would be fascinating to know the inside history of how this policy was adopted.) Simply by highlighting the issue, they have put primate personhood on a serious footing, in a way it never has been before.

It is a commonplace of arguments over “personhood” that on any reasonable, non-arbitrary definition of moral personhood, non-human species might potentially qualify. Defenders of a functional definition of personhood point to this as a feature, not a bug – it is a necessary consequence of the theory’s being non-arbitrary, and it allows for evaluation of claims of personhood on the merits in each case, rather than simply by reference to category (species) membership. Once the possibility of non-human persons is bruited, three suggestions then almost immediately follow: intelligent and sentient space aliens, intelligent computers, and intelligent non-human Earth species, of which the most popular candidates are typically apes, whales and dolphins, and some domesticated animals such as dogs or horses. The first two categories are not represented by any known members, and so are of only theoretical interest, but the question of personhood of animals is of practical significance. “Ethical vegetarians” typicall hold that animals deserve moral consideration, at least to the extent of minimizing suffering or of protection against exploitation; others hold that they qualify for full moral personhood.

Peter Singer became one of the most influential members of the animal-rights movement when he personally adopted an anti-suffering stance, along the lines of Bentham’s famous distinction (“The question is not, ‘Can they reason?’ nor, ‘Can they talk?’ but rather, ‘Can they suffer?’”), and put the animal-rights position on a firm philosophical grounding. More recently he has endorsed the Great Ape Project and taken the position that adult apes of several species should be regarded as moral persons (or, “members of the community of equals”, as the Project puts it, which is a similar but not identical concept). Most philosophers are comfortable with the idea that such a conclusion could make sense, but I think few others believe that it has yet been proven to be true. The fact that a major political party has officially endorsed such a program is unquestionably a milestone.

I think this development is significant in two ways: most obviously because of its potential impact on the animal-rights movement, and also because, in introducing the question of moral personhood for non-humans, the Socialists are implicitly raising the question of the definition of personhood to political prominence. An interesting speculation: the Socialists may have cited genetic evidence of closeness to the human species as the grounding of their position not in spite of the naturalistic fallacy, but because of it. Their position seems to imply that human specieshood is still the definition of personhood, and simply holds that ape species are “close enough” to human to be tucked into the fold as well – thus specifically avoiding a discussion of relative intelligence or mental capacity. If this speculation is correct, then the Socialists have mucked things up but good: bringing in non-humans as a point of contention while the question of personhood for human organisms itself remains controversial. However, if this controversy can be re-centered where it belongs, on a functional definition of intelligence, then it will contribute greatly to elucidating the importance of personhood as a basic moral concept and category – for human individuals as well as members of other species. (I also think this is the only way the animal-rights position can win out – “close enough” on genetic grounds is not good enough morally, especially since the genetic linkage is, as I noted, not so obvious or so close as many people think.)

I would like to see “personhood” given the respect and attention it deserves, especially in the face of the organized, ongoing campaign by religious conservatives to establish human embryos and fetuses as persons, irrespective of circumstances, under US law – as a means of rolling back reproductive autonomy rights. That conversation has been systematically shut out by those who don’t want to hear any suggestion that distinctions can be made between human organisms of any kinds. If the Spanish Socialists succeed in forcing the question of personhood onto the political landscape, they may wind up doing some human persons a great deal of good, whether or not they prove there are any animal persons.