09-01-10

Evidential probability

"The best the logician can do is to recommend gathering more data." Henry E. Kyburg Jr. & Choh Man Teng, p. 200, Cambridge University Press, 2001.


A small series on forgotton (or, let's be optimistic: not yet discovered) pearls of this human endeavour that's called thinking. I learned Mr. Kyburg died a couple of years ago. Given that that ís a fact, one can only hope that he turns out to be an instance of the reference class of great thinkers that have ideas requiring the environment of though of a generation that comes well after their own generation. The series has as its common theme: three B-list philosophers, on which I based my Cognitive Science dissertation (that, recently, became available online by clicking the link "Do Humans Think?' in the top of the right column of this page).

But I'll dispense with the niceties. One can sensibly ask this question: how certain is it that the probability of this coin coming up tails is about one half? Not all coins are the same; and there's evidence of people rigging coins to come up tails more often than our experience with 'normal' or 'average' coins would have us expect. In effect: it's the basic casino fraud to devise a game in which participants expect to have this probability of outcome based on 'everyday' events but where the probabilities of the outcome are drastically different (& skewed toward the offerer of the casino). Maybe, why not?, we should call it a "Humean" fraud because it consists in nothing else then the exploitation of our 'psychological' addiction to straightforward induction - it is the commonest fraud because common sense precisely has it that what happened some way in the past will continue to happen that way in the future.

Explicating this observation has succeeded interesting me in something that I - and not only I - thought to be not particularly interesting: probability. As long as it is the case that philosophy has not integrated probability (and more specifically: Kyburgian probability) at the center of its body of doctrines (the way it did with logic, language, & mathematics in the XXth century) it won't be able to make the next significant and necessary step in its evolution (and, consequently, we humans will not be able to be making the next significant step in our cultural and intellectual evolution).

I'm serious. Dead serious (somewhat aided by the music that's in my ears now - to tell you the whole truth).

Because that's still the towering truth of Hume: we kid ourselves if we believe there's a start for us in certainty. Take the above coin which may or may not be rigged. One perfectly defensible non-probabilistic move might be to say that a rigged coin is not, really, a coin. To say that rigged coins are not a subset of the set of coins poses the type of difficulties grammar-wise that one typically will wabt to avoid but these are in my view not insurmountable difficulties. This move then will keep a pristine & simple probability of one half for tails on all coins and relegate the rigged coins to the class of items that need investigation. This investigation will turn up empty, given there is no statement at all to be made about rigged coins before inspecting a specific coin - and here comes the real problem: there is no statement we can make about any of the coins presented to us prima facie because prima facie it is not possible to make a decision whether or not the coin presented is rigged or not. This is a bummer as it is clear that whatever is presented 'as a coin' is typically non-rigged, and therefore is commonsensically to be attributed with near-certainty the probability of one half - in coming up tails or heads.

That was a painstakingly roundabout way of coming to the following conclusion - in a non-idealized way of seeing the world, we never have probability as such but only an evidence that is more or less corroborating the association of a certain probability to a the type of a certain series of events. Naming (e.g. the naming of certain items as pertaining to the class of 'coins') is the most basic operation; labeling items with the same label is nothing else then saying that, at the level of what is asserted of some thing, there is enough evidence that the labeled item will be as other items with that label have been known to be in the past. Probability comes before the label and not (just or only) after it.

And in the case of labels, or names, we can appreciate why probability is mostly sent off to the outskirts of philosophical and everyday thinking. It makes verbose what is most apparent; that rigged coins are a special subset of coins; that somebody who's bald has between zero and some hairs. Or to try out something again for which I got blasted early on in a 10-year internet career: "Logic always holds but never applies." In most instances our common language has shaped itself around our common way of perceiving our common reality that we can tackle it with the purest deductive logic (with all the limitations that already poses). But when we need to be certain we have to realize the uncertainty of those ways. Not because logic is uncertain (it isn't - also Kyburg's mathematical treatment of evidential probability is certain and non-empty) but because the materials on which our logic operate are terminally uncertain - such that there always is some measurement error & something more of data that needs to be gathered.

Before going all humble and wallowing in guilty feelings of the original 'fallable'-ness of the human kind, let me add this: whatever the limitations of knowledge are - and the history of philosophy is the history of the limit of our knowledge - the knowledge of our limitations is a positive asset. Kyburg's deductions on how to proceed with our inductive reasoning are universally true and inescapable. In all situations in which we would need to use his thought we can be certain that it is sound. The fact that, after using his methods, we wind up with a conclusion that are not wholly certain is not the consequence of his fallibility, of the fallibility of his or other rational thinking - but of the systemic underdeterminedness of our conclusions by our evidence.

To resubmit to the internet another of my epiphanies of old internet-days: "Nothing is true but some things are false." The asymettry of knowledge isn't something that comes on top of knowledge (as, maybe, 'rigged' comes on top of 'coins') but it is an inherent vice of knowledge. I can be conclusive in saying that racism is 'at odds' with knowledge but I can't say that knowledge is conclusively pro-'this or that kind of non racism'. The bummer is that there is a tendency to associate the negative nature of knowledge and truth to mysticism (see as an example in point: Heisenberg): this is a consequence of the psychological fact that we are driven, to take our premises for granted and hence also want to grant that conclusiveness to our conclusions.

Quod non.

(I'll want to reread this once upon a time to make sure it is more than just poetically correct)


Whilst writing this I was listening to: "Earth" feat. Bill Frisell, "The Bee Made Honey in the Lion's Skull" in a genre whose existence I only recently discovered: post-rock or something with as many subgenres as one might expect for a subgenre originatiing in heavy metal ;-)

12:48 Gepost door Guido Nius in Muziek | Permalink | Commentaren (0) | Tags: learning, optimism, kyburg, universals, language |  Facebook |

23-12-09

Book III: Of Morals - Conclusion

"The interest, on which justice is founded, is the greatest imaginable, and extends to all times and places. It cannot be possibly serv'd by any other invention. It is obvious, and discovers itself on the very first formation of society." David Hume, A Treatise of Human Nature, Penguin Classics, 1985, p. 669.


Call it the Roddenberry-principle: you can't imagine, can't conceive of, a society that is composed of intelligent individuals in which there's not a basic notion of justice, & fairness. So much so that even the biggest bands of thieves have some code of law internal to them and that any perturbation of the current laws is invariably justified - with recourse to some 'higher' principle of justice.

That much I consider obvious although it is certainly not obvious that the justice that prevails in any such a conception is just or the fairness so conceived, even remotely, fair. The latter will be my concession to those that like to call their adversaries naïve but it will be a concession made only for the purposes of the argument induced by a reading of Hume which is more particularly my reading. A reading that considers that quite a lot is entailed by Hume's treatment of morals & that consequently lots of the merely contingent human inventions are, in fact, not only just but, also, unavoidable long term consequences of any society where civility is sustained through sufficiently long periods of time (i.e. where no breakdowns are experienced on account of some majority perception that whatever a game life is it basically is a negative sum one in which at least some others need to outright loose before anybody at all can win).

To illustrate my premise:

  • do not say: "despite everything mankind has achieved it still degrades into beastly behaviour";
  • but say: "despite all of those things we do not have yet, doing what is good is still the most common motivator of human action".

When resources are scarce life is a struggle for life and hence a non-zero sum game where this non-zero sum is negative (i.e. necessity knows no law). The denial of this is the essence of the modern political spinning of win-win scenarios that, necessarily, can only be win-win by abstracting the loss to others as irrelevant or unavoidable - & hence the marriage in modern politics between 'realism', 'common sense' & 'win-win' in an attempt to subvert an intuitive longing for cosiness into a blatant disregard for those that loose out 'because they didn't try hard enough'.

But insofar as human invention succeeds in alleviating this struggle for life (to retain only the form of the struggle & the form of the game, where the essence still is non-zero negative sum but where the sum is not expressed in life or death) we'll see, as Hume observes, that we all can gain (at least life-wise) if we focus our energy on the increase of human inventivity and, hence, if we cooperate. So much so that a 'weak' society will, in circumstances of non-scarcity, will tend to win over time from what is a belligerent society (more often than not by inducing internal revolts, within this latter society). Let me say in passing that one of the crucial human inventions that's often forgotten is the invention of reducing the human population by other means than by war, famine or other destruction (and that any cosy politics that avoids 'engineering' the population growth cannot but be unjust and unfair - to be explicit: people without the means for children should first get the means and only then the children - most opting after even the most basic education that they don't want to have children if it means not having a life of their own).

Coming back to the premise illustrated by the above two bullets - the reason why we still have so much problems of injustice and unfairness is because we did not have a sufficient amount of time under which to develop justice and fairness and/or (but for the moment the following is still the most important) because there still is too much scarcity and hence too much struggle by humans to live for us to be able to take the moral high ground. That being as it may it is self-evident that once what will emerge once both conditions are being met with progressively more perfection: the justice of the type argued by Rawls to be fair (but without the artificial reasoning to establish it as it will establish itself as reasonable once scarcity has been suppressed and all the human energy will be dedicated to the struggle for being inventive where individuals will continue to loose but where the whole cannot but win).

More than this: all of this justice as fairness is entailed by the very first justice in the Humean sense. The progress is not one of content (because there is only form to it, and no content, see elsewhere) but one of increasing applicability both class-wise (in a first movement) and geography-wise (in a second movement). This progress can't but be accompanied by an at least perceived loss of some individuals (that are used to winning at the expense of others in a condition of scarcity). The latter is what war, essentially, is made of. The solution does not lie solely - and not even primarily - in coercing the individuals that stand to loose into their loss. Doing this is as stupid (in most - but not all! - contexts) as coercing an unjust and unfair society to adopt what is the established practice of jusice and fairness in more evolved societies (Iraq and Afghanistan spring to mind). Maybe I'll be able to draw out this comparison another time (maybe piggybacking on something in Rawls' Law of Peoples) but suffice to say here that in line with the conception of justice outlined the coercion is in the realm of non-zero negative sum games whilst the patience for evolution counting on the just and the fair being contagious principles is the one that will prove most effective (and just these exceptions where war certainly is justified as an ultimate threat: a lack of education - specifically for women - and a clear breakdown into a less just and more unfair society because of an onset of new scarcity - whatever and whomever is finally the cause of such an onset, the justification of war is independent of who is guilty in bringing about the scarcity - see WWII).

In the end maybe this is the thought: we don't need to engineer people nor society but we do need to engineer away any scarcity of life-threatening tangible goods and if necessary (contra Roddenberry this time) by decreasing the competition for these goods on the demand side (whenever we feel a restriction on the supply side).

(And now I will trun back to language and intention!, for those that were worrying)


Whilst writing this I was listening to Sonny Rollins, soneymoon, Get Back 2007.

15:48 Gepost door Guido Nius in Actualiteit | Permalink | Commentaren (0) | Tags: hume, optimism, imagination, dynamics, universals |  Facebook |

13-12-09

luz casal lyrics (2 candidates)

No aguanto mas:

No necesito sustancias para soñar
prefiero la imaginación
estoy dispuesta a salir de éste callejón
tan solo pido un empujón

Yo necesito desprenderme
quiero respirar
necesito aire, por favor.

un ano de amor:

Y entenderás
en un solo momento
qué significa
un año de amor.

17:09 Gepost door Guido Nius in Algemeen | Permalink | Commentaren (0) |  Facebook |