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    • A precis of the dialogical account of deduction

      By Catarina Dutilh Novaes

      (Cross-posted at M-Phi)

      This is the fourth installment of my series of posts on reductio ad absurdum arguments from a dialogical perspective. Here is Part I, here is Part II, and here is Part III. In this post I offer a précis of the dialogical account of deduction which I have been developing over the last years, which will then allow me to return to the issue of reductio arguments equipped with a new perspective in the next installments. I have presented the basics of this conception in previous posts, but some details of the account have changed, and so it seems like a good idea to spell it out again.

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      In this post, I present a brief account of the general dialogical conception of deduction that I endorse. Its relevance for the present purposes is to show that a dialogical conception of reductio ad absurdum arguments is not in any way ad-hoc; indeed, the claim is that this conception applies to deductive arguments in general, and thus a fortiori to reductio arguments. (But I will argue later on that the dialogical component is even more pronounced in reductio arguments than in other deductive arguments.)

      Let us start with what can be described as functionalist questions pertaining to deductive arguments and deductive proofs. What is the point of deductive proofs? What are they good for? Why do mathematicians bother producing mathematical proofs at all? While these questions are typically ignored by mathematicians, they have been raised and addressed by so-called ‘maverick’ philosophers of mathematics, such as Hersh (1993) and Rav (1999). One promising vantage point to address these questions is the historical development of deductive proof in ancient Greek mathematics,[1] and on this topic the most authoritative study remains (Netz 1999). Netz emphasizes the importance of orality and dialogue for the emergence of classical, ‘Euclidean’ mathematics in ancient Greece:

      Greek mathematics reflects the importance of persuasion. It reflects the role of orality, in the use of formulae, in the structure of proofs… But this orality is regimented into a written form, where vocabulary is limited, presentations follow a relatively rigid pattern… It is at once oral and written… (Netz 1999, 297/8)

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    • Problems with reductio proofs: “jumping to conclusions”

      By Catarina Dutilh Novaes

      (Cross-posted at M-Phi)

      This is the third installment of my series of posts on reductio ad absurdum arguments from a dialogical perspective. Here is Part I, and here is Part II. In this post I discuss issues pertaining specifically to the last step in a reductio argument, namely that of going from reaching absurdity to concluding the contradictory of the initial hypothesis.

      ============================

      One worry we may have concerning reductio arguments is what could be described as ‘the culprit problem’. This is not a worry clearly formulated in the protocols previously described, but one which has been raised a number of times when I presented this material to different audiences. The basic problem is: we start with the initial assumption, which we intend to prove to be false, but along the way we avail ourselves to auxiliary hypotheses/premises. Now, it is the conjunction of all these premises and hypotheses that lead to absurdity, and it is not immediately clear whether we can single out one of them as the culprit to be rejected. For all we know, others may be to blame, and so there seems to be some arbitrariness involved in singling out one specific ingredient as responsible for things turning sour.

      To be sure, in most practical cases this will not be a real concern; typically, the auxiliary premises we avail ourselves to are statements on which we have a high degree of epistemic confidence (for example, because they have been established by proofs that we recognize as correct). But it remains of philosophical significance that absurdity typically arises from the interaction between numerous elements, any of which can, in theory at least, be held to be responsible for the absurdity. A reductio argument, however, relies on the somewhat contentious assumption that we can isolate the culprit.

      However, culprit considerations do not seem to be what motivates Fabio’s dramatic description of this last step as “an act of faith that I must do, a sacrifice I make”. Why is this step problematic then? Well, in first instance, what is established by leading the initial hypothesis to absurdity is that it is a bad idea to maintain this hypothesis (assuming that it can be reliably singled out as the culprit, e.g. if the auxiliary premises are beyond doubt). How does one go from it being a bad idea to maintain the hypothesis to it being a good idea to maintain its contradictory?

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    • APDA Update

      A few weeks ago I posted some details about a new project: Academic Placement Data and Analysis (APDA) here. Readers may be interested in some updates to that project. Note: We are sending out emails to program representatives over the next few hours with much of this information, including an extended collection goal date of July 22nd, 2015. The original blogpost is quoted below.

      1) Total Placement Records

      "There are approximately 2300 total entries, with several categories of data."

      As of noon on July 13th, we had 3078 placement records for 2444 people–that is 573 more placed candidates than we had in the database on June 23rd. (In comparison, PhilJobs, the next most comprehensive database, had 2307 placement records for junior hires at that same time.)

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    • Problems with reductio proofs: assuming the impossible

      By Catarina Dutilh Novaes

       (Cross-posted at M-Phi)

      This is a series of posts with sections of the paper on reductio ad absurdum from a dialogical perspective that I am working on right now. This is Part II, here is Part I. In this post I discuss issues in connection with the first step in a reductio argument, that of assuming the impossible.

      =====================

      We can think of a reductio ad absurdum as having three main components, following Proclus’ description:

      (i) Assuming the initial hypothesis.

      (ii) Leading the hypothesis to absurdity.

      (iii) Concluding the contradictory of the initial hypothesis.

      I discuss two problems pertaining to (i) in this post, and two problems pertaining to (iii) in the next post. (ii) is not itself unproblematic, and we have seen for example that Maria worries whether the ‘usual’ rules for reasoning still apply once we’ve entered the impossible world established by (i). Moreover, the problematic status of (i) arises to a great extent from its perceived pragmatic conflict with (ii). But the focus will be on issues arising in connection with (i) and (iii).

      A reductio proof starts with the assumption of precisely that which we want to prove is impossible (or false). As we’ve seen, this seems to create a feeling of cognitive dissonance in (some) reasoners: “I do not know what is true and what I pretend [to be] true.” (Maria) This may seem surprising at first sight: don’t we all regularly reason on the basis of false propositions, such as in counterfactual reasoning? (“If I had eaten a proper meal earlier today, I wouldn’t be so damn hungry now!”) However, as a matter of fact, there is considerable empirical evidence suggesting that dissociating one’s beliefs from reasoning is a very complex task, cognitively speaking (to ‘pretend that something is true’, in Maria’s terms). The belief bias literature, for example, has amply demonstrated the effect of belief on reasoning, even when participants are told to focus only on the connections between premises and conclusions. Moreover, empirical studies of reasoning behavior among adults with low to no schooling show their reluctance to reason with premises of which they have no knowledge (Harris 2000; Dutilh Novaes 2013). From this perspective, reasoning on the basis of hypotheses or suppositions may well be something that requires some sort of training (e.g. schooling) to be mastered.

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    • Political Disputes Are Moral Disputes

      By:  Samir Chopra

      Writing for The Stone, ('Can Moral Disputes Be Resolved?', New York Times, 13 July 2015), Alex Rosenberg claims:

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    • Problems with reductio proofs: cognitive aspects

      By Catarina Dutilh Novaes

      (Cross-posted at M-Phi)

      As some readers may recall, I ran a couple of posts on reductio proofs from a dialogical perspective quite some time ago (here and here). I am now *finally* writing the paper where I systematize the account. In the coming days I'll be posting sections of the paper; as always, feedback is most welcome! The first part will focus on what seem to be the cognitive challenges that reasoners face when formulating reductio arguments.

       =========================

      For philosophers and mathematicians having been suitably ‘indoctrinated’ in the relevant methodologies, the issues pertaining to reductio ad absurdum arguments may not become immediately apparent, given their familiarity with the technique. And so, to get a sense of what is problematic about these arguments, let us start with a somewhat dramatic but in fact quite accurate account of what we could describe as the ‘phenomenology’ of producing a reductio argument, in the words of math education researcher U. Leron:

      We begin the proof with a declaration that we are about to enter a false, impossible world, and all our subsequent efforts are directed towards ‘destroying’ this world, proving it is indeed false and impossible. (Leron 1985, 323)

      In other words, we are first required to postulate this impossible world (which we know to be impossible, given that our very goal is to refute the initial hypothesis), and then required to show that this impossible world is indeed impossible. The first step already raises a number of issues (to be discussed shortly), but the tension between the two main steps (postulating a world, as it were, and then proceeding towards destroying it) is perhaps even more striking. As it so happens, these are not the only two issues that arise once one starts digging deeper. 

      To obtain a better grasp of the puzzling nature of reductio arguments, let us start with a discussion of why these arguments appear to be cognitively demanding – that is, if we are to believe findings in the math education literature as well as anecdotal evidence (e.g. of those with experience teaching the technique to students). This will offer a suitable framework to formulate further issues later on.

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    • Substantive Equality and Juridical vs. Statistical Biopower

      By Gordon Hull

      The legal doctrine of substantive equality – roughly, that one look at not just the presence of stipulated, formal equality, but that one incorporate outcomes as relevant to whether or not equality has been reached – strikes me as a biopolitical concept, whereas its more formal counterpart is more juridical.  Consider the right to abortion: a formal declaration that a woman has the right to terminate a pregnancy prior to fetal viability exists whenever laws do not prohibit the termination.  Recent state laws that ban all abortions after a gestational age of 20 weeks run afoul of that right, because a fetus at 20 gestational weeks is not viable.  On the other hand, if the right is substantive, then it matters whether women can actually take advantage of the right.  State laws that require spousal consent, for example, were declared by the Court in Planned Parenthood v. Casey to place an “undue burden” on the exercise of that right.  That’s a decision based on substantive equality, and it treats women not (just) as juridical subjects possessing abstract rights, but as agents in the world trying to achieve the outcomes that such rights are (presumably) designed to allow.  Current rounds of state restrictions on abortion, such as forced transvaginal ultrasounds (on the pretext of ensuring the woman is “fully informed”) or the demand that clinics look like hospitals (for the “safety of women”) seem designed to limit the substantive right to abortion, while preserving it formally.  All of that is a rough-and-ready way of putting the distinction, and there may very well be any number of equality claims in particular where the substantive version doesn’t sound particularly biopolitical.  That’s ok – in what follows, I want to look at education, and to propose that claims of substantive equality, even biopolitically-oriented ones, can differ dramatically in what they claim and how they claim it.

      One of the notable features of Brown v. Board of Education is its reliance on social science evidence indicating the psychological harm of segregation to black children (this is the famous “footnote 11,” which cited a number of recent studies).  In his reflections on Brown, Robert L. Carter, one of the attorneys who argued the case, noted that “we assumed … that educational equality in its strict educational connotations – with its emphasis on the quality of education – was the same as educational quality in its constitutional dimensions” and notes that, in a series of earlier cases, “we turned to expert testimony for the first time,” and supported the argument with two kinds of claims: by “measuring the physical facilities of the proposed black law schools against the existing university holdings and by taking into account the adverse psychological detriment that we contended segregation inflicted on blacks – all of which resulted in a denial of equal education” (Bell, ed., Shades of Brown, p. 22).  The three cases prior to Brown were Sweatt v. Painter, McLaurin v. Oklahoma, and Sipurel v. Oklahoma.  Let’s take them in reverse chronological order.

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    • Profanity Inflation, Profanity Migration, and the Paradox of Prohibition

      by Eric Schwitzgebel

      As a fan of profane language judiciously employed, I fear that the best profanities of English are cheapening from overuse — or worse, that our impulses to offend through profane language are beginning to shift away from harmless terms toward more harmful ones.

      I am inspired to these thoughts by Rebecca Roache‘s recent Philosophy Bites podcast on swearing.

      Roache distinguishes between objectionable slurs (especially racial slurs) and presumably harmless swear words like “fuck”. The latter words, she suggests, should not be forbidden, although she acknowledges that in some contexts it might be inappropriate to use them. Roache also suggests that it’s silly to forbid “fuck” while allowing obvious replacements like “f**k” or “the f-word”. Roache says, “We should swear more, and we shouldn’t use asterisks, and that’s fine.“ (31:20).

      I disagree. Overstating somewhat, I disagree because of this eCard:

      “Fuck” is a treasure of the English language. Speakers of other languages will sometimes even reach across the linguistic divide to relish its profanity. “Fuck” is a treasure precisely because it is forbidden. Its being forbidden is the source of its profane power and emotional vivacity.

      When I was growing up in California in the 1970s, “fuck” was considered the worst of the seven words you can’t say on TV. You would never hear it in the media, or indeed — in my posh little suburb — from any adults, except maybe, very rarely, from some wild man from somewhere else. I don’t think I heard my parents or any of their friends say the word even once, ever. It wasn’t until fourth grade that I even learned that the word existed. What a powerful word, then, for a child to relish in the quiet of his room, or to suddenly drop on a friend!

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    • Nominations for PSA-WC Highlighted PhilosopHer

      By Roberta Millstein

      Nominations are OPEN for the PSA Women's Caucus new Highlighted PhilosopHer feature, recognizing the work of the Caucus's membership. Nominations need not be from Caucus members (although nominees do), so this is your chance to crow about some of your outstanding colleagues!  Maybe you saw a great talk from a woman philosopher of science during this summer conference season?

      The nomination form is here.  Highlighted PhilosopHers will be featured on the Caucus's blog, Science Visions.

       

    • Demographics of PSA Membership

      By Roberta Millstein

      Miriam Solomon has a post over at Science Visions, the blog of the PSA Women's Caucus, giving a summary of PSA demographics that she has been tracking since the Women’s Caucus began in 2006.  The full text of the reports is linked to from the post.

      An excerpt from Solomon's post:

      It is encouraging to see that the percentage of women in PSA is higher among more junior members, reflecting trends in other fields of philosophy and in academia generally. I am surprised, however, that there has been no statistically significant increase in the percentage of women in PSA over the last 8 years.