Dummett's Backward Road to Frege and to Intuitionism - Tripod

Dummett's Backward Road to Frege and to Intuitionism - Tripod Dummett's Backward Road to Frege and to Intuitionism - Tripod

memberstripod
from memberstripod More from this publisher
09.11.2012 Views

thought in sense (2). And although that thought reflects or mirrors the essence of concepts (my 2003: xix, 31, 217, 272, 301), it is only one way of many to present the truth-condition in question. Thus there is no backward road from the truth-condition to it. Certainly we do not understand the thoughts expressed by statements if we have no idea of the conditions which would make them true or false. But those very thoughts of the truth-conditions are intensional in sense (2), and the truth-conditions are graspable only via such thoughts. Indeed, the thought we grasp is the “idea” we have of the truth-condition. One might be tempted to say that where “F( )” expresses the sense ‘( ) is red’, the truth condition of “Fa” is a’s being red. That is what most of us would say. But can Frege say it? Our world of four objects shows that for Frege, the ontological locus of objective redness as opposed to objective roundness is the realm of sense. And as this is a categorial matter, this is so in every possible world. Is the ontological locus of the truth-condition of “Fa” then the realm of sense? Is it senses, not references, which make our sentences true? Except for cases of indirect reference, no. 12 If we enrich L so as to include sentences expressing propositional attitudes, then thoughts would be logical parts of the truth-conditions of L, since thoughts are the indirect references of such sentences for Frege. And while only thoughts can be believed, and subsentential senses cannot be believed, presumably the subsentential senses composing believed thoughts must also be indirect references by parity of reason. But Dummett’s procedure would still fail for infinitely many languages L* which lack such sentences, and he gives no indication that he is thinking of this limited way out. And there is no backward road to the indirect senses which occur in cases of indirect reference. We would have to include sentences expressing second-order beliefs about beliefs, so as to make first-order indirect senses into second-order indirect references, and so on for any n-level order of beliefs. Thus we would have to admit an infinite series of orders of indirect sense and reference. I think Frege allows and requires that (Dummett agrees, 1981a: 87). 13 But Dummett’s procedure would fail for infinitely 22

many more languages L** which lack various higher orders of propositional attitudes, and again, Dummett gives no indication that he is thinking of this limited way out. That senses are truth-functional, i.e., extensional in sense (1), does not make a backward road possible. To the contrary, it is precisely because senses are truth-functional that the problem of permuting the obviously different senses expressed by “red( )” and “round( )” arises within the confines of truth-functionality. For Frege, the problem of opacity arises, and can be solved by a reference shift in opaque contexts, because things are presented in different ways. That things are presented in different ways is not a problem but the pre-philosophical truth grounding the sense-reference distinction, implying the “no backward road” thesis as its alter ego, and underlying both the problem of opacity and Frege’s solution. This is why senses (1) and (2) of “extensional” must not be blurred. It is also why Dummett’s emendation of accepting Frege’s shift of reference from customary reference to customary sense (indirect reference) in opaque contexts, but omitting Frege’s shift of sense from customary sense to indirect sense, logically concerns only the problem of oratio obliqua, and is too shallow to touch the general “problem” of no backward road, pace Dummett (1981a: 87). For things are presented to us in different ways even if our language has no opaque contexts. Of course, Dummett could insist on his interpretation and say the problems are Frege’s. But my interpretation avoids the problems. Frege can easily construct L by explicating his eight primitive logical names, explicating “a,” “b,” “c,” and “d” as primitive names of concrete objects, and by either explicating “F( )” as expressing a primitive sense, say, that of “red,” or defining “F( )” as expressing a complex sense, say, that of “red and round,” or defining “F( )” extensionally as the concept under which a, b, and c, but not d, fall. On any of these options we ensure the determinacy of all names by ensuring that every statement in which they occur has a determinate truth-value. Since we introduced only names which can occur in sentences, and since we ensured that all statements of L have a determinate truth-value, the context principle is satisfied for senses and references alike. The only thing 23

many more languages L** which lack various higher orders of propositional attitudes, <strong>and</strong> again,<br />

Dummett gives no indication that he is thinking of this limited way out.<br />

That senses are truth-functional, i.e., extensional in sense (1), does not make a backward road<br />

possible. To the contrary, it is precisely because senses are truth-functional that the problem of<br />

permuting the obviously different senses expressed by “red( )” <strong>and</strong> “round( )” arises within the confines<br />

of truth-functionality. For <strong>Frege</strong>, the problem of opacity arises, <strong>and</strong> can be solved by a reference shift in<br />

opaque contexts, because things are presented in different ways. That things are presented in different<br />

ways is not a problem but the pre-philosophical truth grounding the sense-reference distinction,<br />

implying the “no backward road” thesis as its alter ego, <strong>and</strong> underlying both the problem of opacity<br />

<strong>and</strong> <strong>Frege</strong>’s solution. This is why senses (1) <strong>and</strong> (2) of “extensional” must not be blurred. It is also why<br />

Dummett’s emendation of accepting <strong>Frege</strong>’s shift of reference from cus<strong>to</strong>mary reference <strong>to</strong> cus<strong>to</strong>mary<br />

sense (indirect reference) in opaque contexts, but omitting <strong>Frege</strong>’s shift of sense from cus<strong>to</strong>mary sense<br />

<strong>to</strong> indirect sense, logically concerns only the problem of oratio obliqua, <strong>and</strong> is <strong>to</strong>o shallow <strong>to</strong> <strong>to</strong>uch the<br />

general “problem” of no backward road, pace Dummett (1981a: 87). For things are presented <strong>to</strong> us in<br />

different ways even if our language has no opaque contexts.<br />

Of course, Dummett could insist on his interpretation <strong>and</strong> say the problems are <strong>Frege</strong>’s. But my<br />

interpretation avoids the problems. <strong>Frege</strong> can easily construct L by explicating his eight primitive<br />

logical names, explicating “a,” “b,” “c,” <strong>and</strong> “d” as primitive names of concrete objects, <strong>and</strong> by either<br />

explicating “F( )” as expressing a primitive sense, say, that of “red,” or defining “F( )” as expressing a<br />

complex sense, say, that of “red <strong>and</strong> round,” or defining “F( )” extensionally as the concept under<br />

which a, b, <strong>and</strong> c, but not d, fall. On any of these options we ensure the determinacy of all names by<br />

ensuring that every statement in which they occur has a determinate truth-value. Since we introduced<br />

only names which can occur in sentences, <strong>and</strong> since we ensured that all statements of L have a<br />

determinate truth-value, the context principle is satisfied for senses <strong>and</strong> references alike. The only thing<br />

23

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!