Evolving Thoughts

Evolution, culture, philosophy and chocolate! John Wilkins' continuing struggle to come to terms with impermanence... "Humanus sum, nihil humanum a me alienum puto" - Terence

Thursday, February 17, 2005

A fine and privative place

Officials Warn of Future Terror Attacks: "Director Robert Mueller expressed worry that a sleeper operative in the U.S. may have been in place for years, awaiting orders for an attack.

'I remain very concerned about what we are not seeing,' Mueller said in remarks he submitted to the senators."
What we are not seeing is the sort of attack on our way of life that the hysterical have claimed we will see. It is a problem if you are trying to get funding for a multi-trillion dollar war, the primary purpose of which is to bolster support for a particular government and political party. So of course you have to say that the absence of evidence of this terrorist threat to American and western society in general is evidence that it is happening.

Terrorism is a fairly economical way to fight a war - you have only to cause dramatic harm to some small number of people, and the target country does the rest of the harm for you. What we have witnessed is trillions of dollars/pounds being spent to fight a war while the west becomes the sort of narrow-minded and religiously intolerant society that the terrorists themselves live in. We have met the Taliban, and it is us.

They hate secularism. They are much more comfortable dealing with a society like their own - the stakes and gambits are much clearer. So abandoning secularism, open society, and rule of law the way we have done is playing right into their hands. Modernism is the enemy. If we abandon it, they win, even if they lose.

But that is not why this blog entry. I am amused by the privative nature of the comment. Privation, as I'm sure you all learned in grade school, is classification of a group of things, or the definition of a class, in terms of what they are/it is not. Of course, this causes some trouble. It is no coincidence that William Dembski's "Explanatory Filter" that allows one to conclude life was designed specifies "design" as a privative class (the "set-theoretic complement of the disjunction of regularity-or-chance", Design Inference p50; thanks to Sahotra Sarkar for the ref). Basically, "design" is just everything that is not something else - in this case, explanation by law or chance.

The problem with privative categories is that they are massively sensitive to what you expect. If you expect terrorism, then of course a lack of it is worrying. If you expect that everything is a vertebrate, then everything else is an invertebrate, as Lamarck defined them. But as Nelson and Platnick observe in a much-underappreciated book, rocks are not vertebrates. Are they invertebrates? If you don't think so, ask what you expected to be included in the wider group that "vertebrates" are selected out of. Is is Life? Multicellular organisms? Animals? Now justify the choice of that particular wider category.

Aristotle knew about this. In the The History of Animals, he discusses why privative terms are not proper to classification (book I, chapter 3):
… privative terms inevitably form one branch of dichotomous division, as we see in the proposed dichotomies. But privative terms in their character of privatives admit of no subdivision. For there can be no specific forms of a negation, of Featherless for instance or of Footless, as there are of Feathered and of Footed. Yet a generic differentia must be subdivisible; for otherwise what is there that makes it generic rather than specific? There are to be found generic, that is specifically subdivisible, differentiae; Feathered for instance and Footed. For feathers are divisible into Barbed and Unbarbed, and feet into Manycleft, and Twocleft, like those of animals with bifid hoofs, and Uncleft or Undivided, like those of animals with solid hoofs. Now even with differentiae capable of this specific subdivision it is difficult enough so to make the classification, as that each animal shall be comprehended in some one subdivision and in not more than one; but far more difficult, nay impossible, is it to do this, if we start with a dichotomy into two contradictories. (Suppose for instance we start with the two contradictories, Feathered and Unfeathered; we shall find that the ant, the glowworm, and some other animals fall under both divisions.) For each differentia must be presented by some species. There must be some species, therefore, under the privative heading. Now specifically distinct animals cannot present in their essence a common undifferentiated element, but any apparently common element must really be differentiated. (Bird and Man for instance are both Twofooted, but their two-footedness is diverse and differentiated. So any two sanguineous groups must have some difference in their blood, if their blood is part of their essence.) From this it follows that a privative term, being insusceptible of differentiation, cannot be a generic differentia; for, if it were, there would be a common undifferentiated element in two different groups.
Stripped of the logical phrasing Aristotle invented, in effect he is saying that if you have a privative classification, then you have no simple and clear way to exclude all kinds of things. And that is why I am saying that what remains once the positive class is excluded from the wider set depends entirely on what you expect to see in the first place. It's subjective and arbitrary.

I know this is a long way from terrorism, but the rules of logic are universal (arguably). We ought to worry about what we actually do see, not what we might not see. As I look around, I see the loss of traditional rights, the inclusion of religious conviction into public policy and the consequent imposition of that conviction on others, the control of the media and the debate by those in power... all the kinds of things that once caused a revolution in a certain nation.

Power corrupts. One of the things it corrupts is debate.

Nelson, Gareth J., and Norman I. Platnick. 1981. Systematics and biogeography: cladistics and vicariance. New York: Columbia University Press.