Archive for Rationality

the [h]edge of reason [book review]

Posted in Books, pictures, University life with tags , , , , , , , , , , , , , , on September 4, 2017 by xi'an

I do not know if Julian Baggini chose the title of this book in connection with the second [appalling] Bridget Jones film or with the huge number of books with this title, but the proximity is somewhat unfortunate for a philosophy book!

I presume I got this book based on the subtitle “A rational skeptic in an irrational world”, although I knew nothing of the author and should have done some research before putting my stash of Amazon credit to use! (He has written so many books on philosophical themes that he reminds me of Michel Onfray… And not only for this reason, they also seem to cater to the same readership interested in light or “general public” philosophy. Or as I would call it, journalosophy…)

This thin conception sees rational argument not as a formal, mechanistic, rigid method but simply as the process of giving and assessing objective reasons for belief.” (p.5)

The core idea in the book is that reason is over-rated as an argument in philosophical or every day debate! And should come only as a foot soldier support for one’s beliefs, since those are primordial and unavoidable in leading one’s life, beliefs (!), and principles… Beliefs and presuppositions are central to those and cannot browbeated by reason. I was hoping for a stronger defence of rationality that would set reason at the centre of scientific, democratic, and everyday debates, but I feel the book ends up as at best lukewarm on that front.

“It is always rebarbative  to the philosopher to reach a point in an argument where it is necessary to  admit that others may be presented with the same chain of inferences yet justifiably reach a different conclusion.” (p.9)

The book almost immediately lost most of its potential appeal for me when I realised the very first chapter is about religion and the author seems to find particularly distasteful that “there are some who argue that faith defies reason” (p.17). Followed by a relativistic argumentation that sets religious people and atheists at the same ground level as having different “properly basic beliefs ” (p.21) and “evidence bases” and “rational coherence” (p.17).  Culminating in advocating a “rational Catholicism” (p.133, capitalised by my spell-checker!). At which point I feel we already are on the wrong side of the hedge of reason… From there, the same relativism permeates the whole book, backed up by the argument that there is rarely if ever enough evidence to conclude one way against another (as we would know, of course!). This is particularly jarring in the chapter about science, crucially entitled “Science for humans”, which argues that there is no such thing as pure science, because scientists always contaminate scientific arguments (and data?) with their beliefs and prejudices. As in e.g., “the question of whether or not an experiment or observation counts as critical – sufficient to settle a dispute – is itself a judgement (p.47). The more I read the book the more I felt it carried a postmodernist message, even when stating the opposite (p.238) as aiming at skepticism (p.234) or making fun of the most extreme illustrations of this obscurantism (p.100, p.125). Putting for instance some of the blame “on both sides”, post-modernists and anti-post-modernists alike (p.238)!

“Reason is thin ice on which we have no choice but to skate.” (p.245)

A last comment about the application of those relative principles to state government and society ruling (Part IV: The King). The attack on an ideal (Socratic or Platonic) society ruled by reason alone as unimplementable and not pragmatic and “a bad principle” (p.194) does not produce a better alternative proposal than conservatism (!) and the call to reason to fight populism with practical reason (Chapter 11) sounds self-defeating. When opposed with the relativism of the remainder of the book. If societal decisions should be based on rationality and there is no consensus on what rationality is, which is a reason for advocating pluralism, it seems impossible to reach agreement on how to govern and to find an implementable version of pluralism. Which brings us back to stage zero and the feelings leading to populism that the elites have no idea on how to run the polis. Except their self-interest. Speaking of pluralism, the author seems to agree (p.225) that secularism à la française [obviously to be distinguished from political exploitations like last year burkinigate!] is still a form of pluralism precisely because it excludes religion from the public debate. Because arguments can then [at least on principle] reach all members of the polis. (But then I do not understand how “unleashing religious voices in the political public sphere” [p.230] is compatible with this.)

“Some might believe that such a skeptical defence of reason leaves it thin and emaciated.” (p.236)

In conclusion, I am thus quite disappointed by the book and what I consider to be a rather shallow approach to the question of reason in the public debate. Thinning out rationality does not seem like a helpful step to fight anti-rational, fundamentalist, obscurantist, etc. forces, as it does not make these move one inch their ideological positions.

As an update, it is rather unfortunate that this review came out when the North-Korean crisis seems to push the World beyond the edge of reason with threats of nuclear attacks… Which brings us back to the boundless dangers of populism.

is atheism irrational?

Posted in Books, Kids with tags , , , , , , , on March 2, 2014 by xi'an

“If a belief is as likely to be false as to be true, we’d have to say the probability that any particular belief is true is about 50 percent. Now suppose we had a total of 100 independent beliefs (of course, we have many more). Remember that the probability that all of a group of beliefs are true is the multiplication of all their individual probabilities. Even if we set a fairly low bar for reliability — say, that at least two-thirds (67 percent) of our beliefs are true — our overall reliability, given materialism and evolution, is exceedingly low: something like .0004. So if you accept both materialism and evolution, you have good reason to believe that your belief-producing faculties are not reliable.”

On the (New York Times) philosophy blog The Stone, I spotted this entry and first wondered if I had misread the title, as atheism sounds (to me) as a most rational position. I then read the piece and found it mostly missing, even though a few points rang true(r). First, theism is never properly defined. (Even though the author Alvin Plantinga seems to stick to monotheist religions.) This is a not-so-subtle trick as it makes atheism appear as the extreme position, since it is rejecting any form of theism! Then, the interviewee is mostly using a sequence of sophisms as arguments that atheists are irrational, see e.g. the even-star-ism and a-moonism and a-teapotism entries. Further, some of his entries very strongly resemble intelligent design arguments, e.g. the “fine-tuning” line that the universe is too perfectly suited to human life to be due to randomness. Even though Plantinga also resorts to evolution when needed, as in the above quote. (The interviewer is not doing a great job either, by referring to evil, or the need (or lack thereof) of God versus science to explain the world. Rather than resorting to rational arguments. And without mentioning the fundamental point in favour of atheism that the existence of a sentient being driving the whole universe while remaining hidden to us humans requires an infinitely stronger step than arguing this is impossibly incompatible with the laws of Physics and the accumulated corpus of experience since the dawn of humanity.) The whole strategy of Plantinga is actually to turn atheism into another kind of belief “that materialism and evolution are true” and then to rank it equal with the theisms. A very poor philosophical performance. As also (and better) pointed out in this other post. (And as my daughter remarked, fresh from writing a philosophy essay, Plantinga is missing the best argument of all, namely Pascal’s wager, an early instance of decision theory applied to religion.)

May I believe I am a Bayesian?!

Posted in Books, Statistics, University life with tags , , , , , , , , , on January 21, 2012 by xi'an

…the argument is false that because some ideal form of this approach to reasoning seems excellent n theory it therefore follows that in practice using this and only this approach to reasoning is the right thing to do.” Stephen Senn, 2011

Deborah Mayo, Aris Spanos, and Kent Staley have edited a special issue of Rationality, Markets and Morals (RMM) (a rather weird combination, esp. for a journal name!) on “Statistical Science and Philosophy of Science: Where Do (Should) They Meet in 2011 and Beyond?” for which comments are open. Stephen Senn has a paper therein entitled You May Believe You Are a Bayesian But You Are Probably Wrong in his usual witty, entertaining, and… Bayesian-bashing style! I find it very kind of him to allow us to remain in the wrong, very kind indeed…

   

Now, the paper somehow intersects with the comments Stephen made on our review of Harold Jeffreys’ Theory of Probability a while ago. It contains a nice introduction to the four great systems of statistical inference, embodied by de Finetti, Fisher, Jeffreys, and Neyman plus Pearson. The main criticism of Bayesianism à la de Finetti is that it is so perfect as to be outworldish. And, since this perfection is lost in the practical implementation, there is no compelling reason to be a Bayesian. Worse, that all practical Bayesian implementations conflict with Bayesian principles. Hence a Bayesian author “in practice is wrong”. Stephen concludes with a call for eclecticism, quite in line with his usual style since this is likely to antagonise everyone. (I wonder whether or not having no final dot to the paper has a philosophical meaning. Since I have been caught in over-interpreting book covers, I will not say more!) As I will try to explain below, I believe Stephen has paradoxically himself fallen victim of over-theorising/philosophising! (Referring the interested reader to the above post as well as to my comments on Don Fraser’s “Is Bayes posterior quick and dirty confidence?” for more related points. Esp. about Senn’s criticisms of objective Bayes on page 52 that are not so central to this discussion… Same thing for the different notions of probability [p.49] and the relative difficulties of the terms in (2) [p.50]. Deborah Mayo has a ‘deconstructed” version of Stephen’s paper on her blog, with a much deeper if deBayesian philosophical discussion. And then Andrew Jaffe wrote a post in reply to Stephen’s paper. Whose points I cannot discuss for lack of time, but with an interesting mention of Jaynes as missing in Senn’s pantheon.)

  

The Bayesian theory is a theory on how to remain perfect but it does not explain how to become good.” Stephen Senn, 2011

While associating theories with characters is a reasonable rethoretical device, especially with large scale characters as the one above!, I think it deters the reader from a philosophical questioning on the theory behind the (big) man. (In fact, it is a form of bullying or, more politely (?), of having big names shoved down your throat as a form of argument.)  In particular, Stephen freezes the (Bayesian reasoning about the) Bayesian paradigm in its de Finetti phase-state, arguing about what de Finetti thought and believed. While this is historically interesting, I do not see why we should care at the praxis level. (I have made similar comments on this blog about the unpleasant aspects of being associated with one character, esp. the mysterious Reverent Bayes!) But this is not my main point.

…in practice things are not so simple.” Stephen Senn, 2011

The core argument in Senn’s diatribe is that reality is always more complex than the theory allows for and thus that a Bayesian has to compromise on her/his perfect theory with reality/practice in order to reach decisions. A kind of philosophical equivalent to Achille and the tortoise. However, it seems to me that the very fact that the Bayesian paradigm is a learning principle implies that imprecisions and imperfections are naturally endowed into the decision process. Thus avoiding the apparent infinite regress (Regress ins Unendliche) of having to run a Bayesian analysis to derive the prior for the Bayesian analysis at the level below (which is how I interpret Stephen’s first paragraph in Section 3). By refusing the transformation of a perfect albeit ideal Bayesian into a practical if imperfect bayesian (or coherent learner or whatever name that does not sound like being a member of a sect!), Stephen falls short of incorporating the contrainte de réalité into his own paradigm. The further criticisms found about prior justification, construction, evaluation (pp.59-60) are also of that kind, namely preventing the statistician to incorporate a degree of (probabilistic) uncertainty into her/his analysis.

In conclusion, reading Stephen’s piece was a pleasant and thought-provoking moment. I am glad to be allowed to believe I am a Bayesian, even though I do not believe it is a belief! The praxis of thousands of scientists using Bayesian tools with their personal degree of subjective involvement is an evolutive organism that reaches much further than the highly stylised construct of de Finetti (or of de Finetti restaged by Stephen!). And appropriately getting away from claims to being perfect or right. Or even being more philosophical.