معضل فرگه-گیچ و منطق طرز تلقی های مرتبه بالاتر (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
ابرازگرایی اخلاقی مدعی است (1) جملات اخلاقی فاقد شرایط صدق هستند و (2) هدف ما از بیان جملات اخلاقی ابراز طرزتلقی های اخلاقی مثل تمایلات، خشنودی ها و ناخشنودی هایمان است که سرشتی ناشناختی گرایانه دارند. این دیدگاه با مشکل مهمی روبروست که به معضل فرگه-گیچ شهرت یافته است. جملات اخلاقی بخشی از معناشناسی جملات مرکب هستند؛ P (یک جمله اخلاقی) در تناقض با P⁓ قرار می گیرد و منطقاً می توان Q را از P و «اگر P آنگاه Q» استنتاج کرد (استدلال وضع مقدم). ناشناختی گرایان منکر آنند که معنای جملات اخلاقی در جملات مرکب و جملات اتمی یکی است. اگر معنای P در قالب جمله مفرد با معنای آن در مقدمِ جمله شرطیه یکی نباشد، استدلال مذکور نامعتبر خواهد شد، در حالی که می دانیم استدلالی معتبر است. بلکبرن مدعی است جملات مرکب بیانگرِ طرزتلقی های مرتبه بالاتر نسبت به طرزتلقی های مطرح شده در جملاتِ کوچک ترِ تشکیل دهنده آنها هستند. لذا اگر مقدمات یک استدلال معتبر را تأیید و نتیجه آن را انکار کنیم، طرزتلقی های ما دچار تعارض می شوند، همان طور که اگر همزمان به P و P⁓ باور داشته باشیم دچار تناقض می شویم. رویکردِ طرزتلقی های مرتبه بالاتر مشکلات متعددی دارد. پذیرش مقدمات یک استدلال اخلاقی و انکار نتیجه آن، با رویکرد ابرازگرایانه نهایتاً شخص را به تناقض اخلاقی می رساند، نه تناقض منطقی. علاوه بر این، ابرازگرایی از تبیین تناقض آشکارِ حاصل از بیانِ P و P⁓ نیز ناتوان است. راه حل بلکبرن برای ایجاد یک طرزتلقی جدید، مثل مدارا، نیز قادر به حل مشکل نیست.The Frege-Geach Problem and the Logic of Higher-Order Attitudes
Moral expressivism suggests that 1) moral sentences lack truth conditions and 2) our purpose in asserting moral sentences is to express non-cognitive attitudes such as desires, approval, or disapproval. Moral expressivism meets a fundamental challenge, known as the Frege-Geach problem. Sentences that express moral judgments can form part of semantically complex sentences. “P” (a moral sentence) contradicts “~P”, and “Q” follows logically, by modus ponens, from (1) “P” and (2) “if P, then Q”. Geach argued that noncognitivists are committed to denying that moral predicates mean the same thing in embedded contexts as they do in unembedded sentences (atomic sentences). If “P” does not mean the same as the antecedent of (2), the argument would be invalid. The problem is that the above-mentioned argument is obviously valid. Blackburn has argued that the complex sentence expresses a ‘higher-order’ attitude toward the attitudes expressed by the smaller sentences which make it up. If we accept the premises of a valid argument but deny its conclusion our attitudes clash in the same way that they do if we both believe that P and ~P. Blackburn's meta-attitudes approach faces several problems. Someone who endorses the premises but denies the conclusion of the valid argument commits himself to a moral inconsistency, not a logical one. In addition, uttering both ‘P’ and ‘~P’ seem to be inconsistent but expressivism cannot explain the inconsistency between these two obviously inconsistent sentences. Blackburn's strategy of inventing a new attitude, such as tolerance, is also unable to solve this problem.IntroductionMoral expressivism suggests that 1) moral sentences lack truth conditions (negative claim) and 2) our purpose in asserting moral sentences is to express non-cognitive attitudes such as desires, approval, or disapproval (positive claim). Moral expressivism meets a fundamental challenge known as the Frege-Geach problem (Geach, 1960, 1965). In the following, the Frege-Geach problem and Simon Blackburn’s response to it will be examined. Blackburn has developed several different answers to the Frege-Geach Problem In this article, only the answer which appeals to the higher-order attitudes (Blackburn, 1984) will be examined, and it will be shown that this expressivist recipe can not solve the Frege-Geach problem.The Frege-Geach problemThe Frege-Geach problem is the idea that moral predicate functions as a ‘logical’ one sothat sentences containing this predicate enter into logical relations with other sentences. Sentences that express moral judgments can form part of semantically complex sentences. “P”(a moral sentence) contradicts “~P”, and “Q” follows logically, by modus ponens, from (1) “P” and (2) “if P, then Q”. Geach argued that noncognitivists are committed to denying that moral predicates mean the same thing in embedded contexts as they do in unembedded sentences (atomic sentences). They cannot explain that the meaning of complex sentences is in termsof the meanings of their parts. They cannot explain why modus ponens arguments are always valid. Arguments of the form of modus ponens, according to expressivism, commit a fallacyof equivocation; because it appears to imply that “P” does have different meanings in premise (1) and in the antecedent of premise (2). “P” is asserted in premise (1) and remains unassertedin premise (2). The utterance of (2) does not seem to express approval or disapproval of “P”. If “P” does not mean the same as the antecedent of (2), the argument would be invalid. The problem is that the abovementioned argument is obviously valid. Geach (Geach, 1960, p. 223) calls this point about assertion the Frege point who was the first logician who made the pointin his distinction between the sense and the reference of a sentence. “A thought may havejust the same content whether you assent to its truth or not; a proposition may occur in discourse now asserted, now unasserted, and yet be recognizably the same proposition” (Geach, 1965,p. 449).The higher-order attitudesBlackburn denies that any of his claims entail valid moral arguments are invalid. He employs an account of what we are doing when we use ethical sentences in terms of expressing meta-attitudes about a moral sensibility; The complex sentence expresses a ‘higher-order’ attitude toward the attitudes expressed by the smaller sentences which make it up. There are logical relationships that exist among attitudes as there are among beliefs. If we accept the premises of a valid argument but deny its conclusion, our attitudes clash in the same way they do if we both believe that P and ~P. So we can explain the logical validity of the moral argument via the attitudes one can hold without clash; anyone approving (1) “P” and (2) “if P, then Q” must hold the consequential approval of “Q”. If he does not, his attitudes clash. The inconsistency originates from the clash of attitudes (failing to do something which one has committed oneself to do). Blackburn says that such a clash would involve a “fractured sensibility which cannot itself be an object of approval” because “such a sensibility cannot fulfill the practical purposes for which we evaluate things” (Blackburn, 1984, p. 195).Logical conflict and moral conflictThere is a most important problem with this strategy for Blackburn’s expressivism. The clash of attitudes can only show moral conflict and moral conflict does not necessarily lead to logical inconsistency. What needs to be explained in the moral argument is a logical inconsistency. Moreover, as Mark van Roojen (1996, pp. 21-320) has pointed out, higher-order-attitudes logic commits us to believe in logical inconsistency where there is no such inconsistency. He considers the origin of this problem to be the confusion between logical inconsistency and practical inconsistency (van Roojen, 1996, p. 332).The negation problemThe other problem for Blackburn’s expressivism was originally raised by Unwin (Nicholas Unwin, 1999, 2001). This problem is known as the ‘negation problem’. As Schroeder points out (Schroeder, 2010, p. 134), the negation problem is the same as the Frege-Geach problem, which has received more attention in recent years than its conditional form, which is presented in the modus ponens argument. The most important semantic property of the negation operator in descriptive sentences is that it makes the negated sentence inconsistent with the main sentence, in the sense that for any sentence ‘P’, ‘P’ is inconsistent with ‘~P’. According to expressivism, “murdering is wrong” (P) is used to express the attitude of disapproval towards the act of murdering. But what is expressed by “murdering is not wrong” (~P)? To utter both ‘P’ and ‘~P’ seems to be inconsistent but expressivism cannot explain the inconsistency between these two obviously inconsistent sentences; because it cannot tell us which state of mind is expressed in the moral sentences like “murdering is not wrong.” To avoid the problem, Blackburn (Blackburn, 1988, p. 189) introduces a new attitude, such as tolerance, and says that “murdering is wrong” expresses disapproval of murdering, and “murdering is not wrong” expresses tolerance of murdering. “Tolerance toward P (T!p) is equivalent to not hooraying ~p, that is, not booing p.” (Blackburn, 1988, p. 189). But there is a real difference between not accepting something and actually accepting its negation (Unwin, 1999, p. 341).ConclusionAccording to Blackburn, We are expressing our attitudes about a moral sensibility when we use ethical sentences. The question now is whether Blackburn can explain the validity of the inference from the premises of the argument to its conclusion through this strategy. This article has shown that Blackburn’s meta-attitudes approach faces several problems. Someone who endorses the premises but denies the conclusion of the valid argument commits himself to a moral inconsistency, not a logical one. In addition, expressivism has insufficient structure to account for the various ways in which a moral sentence can be negated because it cannot tell us which state of mind is expressed in moral sentences like “murdering is not wrong.” Blackburn’s strategy of inventing a new attitude, such as tolerance, is also unable to solve this problem.
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