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Tully Borland
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Now given these explanations of key terms, it seems that validity, invalidity, and correctness are purely factual, and thus purely non-normative, properties of arguments/reasonings. But there is "truth" in the definition. The premises need to be true, i.e. correct, i.e. right. Or are you not buying that truth is normative? I also wonder about "permissible"/"obligatory" in the conclusions. Is it morally obligatory not to give affirming the consequent argument forms? I should think the "ought" in the conclusion would be one of rationality or proper function but not morality. How about this: 1. Affirming the Consequent is an invalid argument form. 2. Thus it ought not be employed as if it were valid. The "ought" would be an ought of proper function. Given the nature of affirming the consequent, it has a proper function (to crank out conclusions that don't follow from premises). If you want to use the argument form as an example in a classroom to illustrate an invalid argument form, go for it. But if you want to use it as if it were valid, you're being irrational for its nature prevents it from ever being valid. Perhaps argument forms don't have natures but then maybe that line of thought would still work with something that does.
Great stuff, Maverick—both this post and the previous one. I must admit that I’m shooting from the hip here and appreciate your patient indulgence. I do find this subject very interesting even if I’m certainly no expert in this area. My demand for a valid instance of such a move might be rejected as an impossible demand. I might be told that there are no purely factual premises and that if, per impossible, there were some, then of course nothing normative could be extracted from them. This was actually my first inclination in reading your first couple posts on the issue. If we can’t allow any explicit normative words (or concepts) in the categorical premises, and we have to use all categorical statements (no “if fact, then ought” bridge principles), and we can’t have an assumed normative premise such that the argument is an enthymeme, and we’re working with (what you refer to as) syntactical validity, then the project seems obviously doomed from the start. At least it did to me when I first came across the challenge. That’s why some of my arguments haven’t been syntactically valid. So if there is a way to get from factual premises to an explicitly normative conclusion I think we’re going to have to adopt some other understanding of validity than syntactical validity. Consider something like (D3) or (D4) hereby adopted. But if the content of the premises are purely factual (and we can’t have any assumed premises the content of which is normative), then what are we left with to get normativity into the conclusion? Well, there is (a) the truth of the premises, (b) the nature of the premises (assertions purporting to be evidence), and (c) the process of inferential reasoning itself. This latter notion was what I was invoking in my last comment that you didn’t understand. So please allow me start here again, and then I’ll return to (a) and your most recent post in a separate comment when I get the chance. Even if what I say about (c) fails, it will hopefully be somewhat more intelligible (if it is intelligible!). In making an inference, we take for granted in the inferential process itself that we’re engaged in that the conclusion ought to be believed or at least ought to be given greater or lesser credence given the premises. When I assert “p, thus ~p” I take for granted the proposition that "~p should be given less credence than p" (in this case, zero credence). But what I’m suggesting is that, perhaps we should think that engaging in the inferential process itself provides the justification for the explicit normativity in the conclusion. 1. P 2. Thus, ~p. 3. Thus, ~p should be given less credence. I’m suggesting that the inferential process itself justifies the further move to 3, and I’m also suggesting that there’s no normative premise being smuggled in. (Maybe this won’t work but it’s worth a try). Here is an analogy to motivate that latter claim. When I reason inferentially using modus ponens (when I engage in the process), in order for that process to be the truth preserving process that it is, the following proposition must be true (if p & (if p then q), then necessarily q). But that proposition is not an implied premise in the argument. I’m justified in believing the conclusion because I’m justified in believing the premises and the inferential process is a truth preserving one. What I’m suggesting is that, similarly, perhaps it’s the case that I’m justified in believing (3) because I’m justified in believing (1) and (2), and by engaging in the process of inferential reasoning itself, I’m further justified in believing 3.
Toggle Commented Feb 27, 2014 on Truth and Normativity at Maverick Philosopher
Bill, I spoke falsely when I said "for the last time". I'm going to try this again because I'm either confused or not being clear enough or both. And, yes, I understand what we're looking for. My (2) was ambiguous. I meant that one ought to believe the disjunctive statement p v q, not simply p (as you interpreted it). From p by addition we can derive p v q. But you don't think we can further derive "one ought to believe p v q"? But if I'm offering you 1. p 2. Thus, p v q then am I not giving an argument for p v q and thereby presenting reasons for p v q such that it's to be believed? But I have my own worries about that first example so maybe here's a better one. From p by the law of non-contradiction we can derive ~p. So I offer you the following argument: 1. p 2. Thus, ~p. Shouldn't one also conclude from that argument that one should not believe~p? Is that not implied as well by p? You might say, "No, Tully, you're smuggling in a conditional premise "if p and the law of non-contradiction, then one shouldn't believe ~p." But I'm suggesting that this needn't be the case. I'm suggesting that, in the same way that we don't invoke the proposition "if (p then q) and p, thus necessarily q" when employing (the inferential process) modus ponens, so too we needn't invoke "if p and the law of non-contradiction, then one shouldn't believe ~p" in concluding that one shouldn't believe ~p.
Thanks for hashing this out with me. One last attempt.... Let me try to simplify things with another shorter argument, ignoring for the moment "whatever is true ought to be believed": 1. 2+2=4. 2. Thus, one ought to believe that 2+2=4 or the Steelers won a Super Bowl in the 70's. 2 follows from 1 + the employment of addition. Formally, the "one ought to believe that" complicates matters; but not only that (p v q) but that (p v q ought to be believed given p) seems also to be implied by p and the use of addition. Now maybe if a terrorist puts a gun to my head and says that if I believe 2 on the basis of 1 then I'll be shot, then there's a sense in which I shouldn't affirm the argument, but to me this would be a case of conflicting norms (and I should pray that by some miracle my brain is quickly rewired). But then have I derived a normative fact from a factual one without any implicit premises? Here's a thought: the move from the norm is justified by the justification for (1) and the process of reasoning itself and not by any other assumed propositions.
All good points, Bill. The reason for the parenthetical remarks in the argument I gave was (a) to be clear about where I'm cheating if I'm cheating but also (b) because I think the argument I gave sans parentheses is valid. Granted, it's not formally valid without the parenthetical propositions (it would be a bad example if I were teaching modern logic), but it does seem to me that if the first premise is true then 2 and 3 must be true. Is that cheating? I don't know. Would using modus ponens be cheating? Implicit in using modus ponens is that I think it is a correct form of inference; it's a good form of inference. Am I smuggling in the proposition "'p and (if p, then q), then necessarily q' is right" if a make a purported argument from factual premises to a normative conclusion? Maybe not, but there is some sense, it seems to me, in which I am assuming normativity in affirming the conclusion based on the argument. (Of course since Hume was willing to call into question induction maybe upon further thought he would call into question deduction and abduction as well. In which case, it may not be above board of Hume--or others like him--to ask for an argument from factual premises to a normative conclusion). "One ought to believe what is true." How [to] justify this? Why is it never morally permissible to disbelieve what is true? I wasn't trying to suggest that one morally ought to believe what is true (I'm unsure about that). I'd say moral "oughts" are perhaps a species of a more general normative "ought" (which perhaps is a species...). [Anselm understand truth in terms of rightness and I think there's something to be said for that.] So I was looking for some factual proposition which by its essence entails some normative notion or other. Maybe in this case it's a an "epistemic ought" of rationality or maybe proper function with respect to that segment of my noetic faculties aimed at the production of true belief. Whatever it is, it seems to me that in the simple act of making an argument, I'm committed to there being a sense in which at least one of the assertions ought to be believed. Since we can't escape normativity in our reasoning, the Humean objection loses a lot of its force. Even in the following argument, we're assuming some some normative fact, even if not explicitly stated in the premises: 1. 2+2=4 2. If 2+2=4 then squares aren't round. 3. Thus squares aren't round.
"But one ought to question the strict bifurcation of fact and value." I agree, since I tend to fancy the medieval doctrine of the equivalence of being and goodness. But here might be another example to motivate the pervasiveness of value in "factual" statements. Let's try this out: 1. It is snowing. 2. Thus, "it is snowing" is true (from p one can deduce that "p is true"). 3. Thus, one ought to believe p and disbelieve ~p (since one ought to believe what is true and disbelieve contradictions). Any assertion in ordinary contexts (of what is believed) carries with it an implicit norm that it is to be believed because it is true. If that's right, then to think that there are many factual claims from which no norm can be deduced would be to fall into a pretty radical skepticism and perhaps even incoherence.
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Feb 26, 2014