Recap. Contents EMPIRICISM. Reductionism and Idealism. Early Carnap. Game plan. Reading and final essay. Recap: Russell s phenomenalism

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1 Contents EMPIRICISM PHIL3072, ANU, 2015 Jason Grossman Game plan Recap Russell, Einstein, and Idealism Early Carnap lecture 10: 29 September Reductionism and Idealism Early Carnap Only five weeks left! Game plan More on logical positivism, mainly through the eyes of: Karl Popper (not himself a logical positivist) A Note on Berkeley as Precursor of Mach and Einstein early Carnap ( Der Logische Aufbau Der Welt (1928) and Philosophy and Logical Syntax (1935)) A J Ayer (main populariser of logical positivism in English) Language, Truth and Logic (and probably skipping Neurath) Late Carnap on frameworks ( Empiricism, Semantics and Ontology ) Quine, especially Two Dogmas of Empiricism Hopefully: Theory and Observation in Science (Maxwell and Hanson) Hopefully: more on principles of rationality Hopefully: post-quinean empiricists Huw Price, Stephen Yablo and Arthur Fine Reading and final essay I ve renamed some of the required reading on the web site to additional reading (If you ve already done it it won t be wasted) Draft final essay topic to be finalised by 20 October, and to be handed in by 13 November Recap Recap: Russell s phenomenalism Hard data: those which resist the solvent influence of critical reflection Bertrand Russell, Our Knowledge of the External World as a Field for Scientific Method in Philosophy, London: George Allen & Unwin, 1914, pp This is a matter of degree What does not go beyond our own personal sensible acquaintance must be for us the most certain Our Knowledge of the External World, p 74 Testimony comes from relatively soft data about other minds This means that almost all our knowledge is soft The existence of tables and chairs can t be justified by common sense because common sense is self-refuting

2 Recap: Knowldege by aquaintance: Russell patterns in my visual field some simple relations eg, before universals, ie abstract ideas ( whiteness, diversity, brotherhood, and so on [and] all verbs ) memories introspection the self maybe 1912, p 81 Recap: Knowledge by acquaintance: Carnap (and Ayer) Gestalts comprising a sort of snap shot of a given time of everything perceived viewed ie not atomism note that perceptions can overlap Recap: Gestalt psychology Recap: Knowledge by description physical objects other people s minds (other) inferences from theories eg, mathematical objects most things, in fact "Grey square optical illusion" by Original by Edward H Adelson, this file by Gustavb - File created by Adrian Pingstone, based on the original created by Edward H Adelson patterns in my visual field What I know by acquaintance some simple relations eg, before universals, ie abstract ideas ( whiteness, diversity, brotherhood, and so on [and] all verbs ) memories introspection the self maybe 1912, pp Recap: Why should we believe all this? it is scarcely conceivable that we can make a judgment without knowing what it is that we are judging about We must attach some meaning to the words we use, if we are to speak significantly and not utter mere noise; and the meaning we attach to our words must be something with which we are acquainted The chief importance of knowledge by description is that it enables us to pass beyond the limits of our private experience 1912, pp 91 92; also available at This is a refinement of a similar doctrine in Hume

3 Recap: The relationship with Idealism The philosophy which I advocate is generally regarded as a species of realism, and accused of inconsistency because of the elements in it which seem contrary to that doctrine For my part, I do not regard the issue between realists and their opponents as a fundamental one Bertrand Russell, Logical Atomism, La Salle: Open Court, 1924/1985, p Reductionism I doubt that this was really true of Russell But it was true of Carnap, as we ll see later And it s a popular view now (eg Simon Blackburn s quasi-realism ) Varied examples of reductionism reductionism often is sceptical whether there is a legitimate inference from B-truths to a different set of A-truths This is why it prefers to reduce the A s down, meaning that the inference is no longer vulnerable It leads nowhere outside the B-range But since this revises the natural beliefs, it hardly gives the meaning of the original concepts, but suggests substitutes It becomes tempting to shelve the question of whether the reductions mean the same as the original statements make sure I have enough slashperiods It becomes tempting to shelve the question of whether the reductions mean the same as the original statements One part of [each reductionist, eg one part of Berkeley and one part of Russell] wants to accept the original discourse the A-statements because, of course, they have identical content with quite legitimate B-statements But another part wants to voice suspicion of the A-statements, because along with the pure content, there is the intruding illegitimate element which disguises it Thus Berkeley presents himself as siding in all things with the mob: his analysis of the world as a community of spirits and ideas allows us to think that there exist tables, chairs etc However, in another mood he will insist that it is a vulgar error to suppose, for example that anything is ever both touched and seen So Berkeley havers over whether the reduced, legitimate content exhausts the actual meaning we can give to statements Russell, Einstein, and Idealism More influence of Einstein on Russell Matter, traditionally, has [some] of those neat properties which are the mark of a logical construction Bertrand Russell, Logical Atomism, La Salle: Open Court, 1924/1985, p 164 What are we to take as data in philosophy? It seems to me that science has a much greater chance of likelihood of being true than any philosophy hitherto advanced (I do not, of course, except my own) Bertrand Russell, Logical Atomism, La Salle: Open Court, 1924/1985, pp We will define a set of compresent events as a minimal region We find that minimal regions form a four-dimensional [Riemann] manifold, and that, by a little logical manipulation, we can construct from them the manifold of space-time that physics requires Bertrand Russell, Logical Atomism, La Salle: Open Court, 1924/1985, p 179

4 What s the point of philosophy, then? Why not just do science? The business of philosophy, as I conceive it, is essentially that of logical analysis, followed by logical synthesis Philosophy should be comprehensive, and should be bold in suggesting hypotheses as to the universe which science is not yet in a position to confirm or confute Bertrand Russell, Logical Atomism, La Salle: Open Court, 1924/1985, p 178 A very important part of this (in my opinion, and I think Russell s) is that philosophers should not be naïve in accepting all scientists claims PHIL2042 is almost entirely about this Also, Einstein (and others) got much of physics from philosophy Huw Price: philosophy is not an activity after science, in a logical sense In particular, it does not rely on inferences from what best current science says about reality On the contrary, it is itself a kind of formal finishing school for scientific theory Its own products are best current science Huw Price, Quining Naturalism, viewed 12/4/2008 Differences between Idealism and Phenomenalism These apply to Russell s Phenomenalism (including his logical atomism) and to Carnap s Der Logische Aufbau Der Welt (1928) Idealism denies the existence of non-mental entities, but Russell and Carnap don t As in all uses of Occam s razor, one was not obliged to deny the existence of the entities with which one dispensed Bertrand Russell, My Philosophical Development, London: George Allen and Unwin, 1959, p 13 there are usually, if not always, a number of different minimum vocabularies for a given subject-matter Bertrand Russell, The Philosophy of Bertrand Russell, p 15 Idealism was religious in spirit (although not always literally so) Russell and Carnap were not at all religious Russell and Carnap were thoroughly fallibilist Idealists varied on this As a result of all of the above differences, Russell and Carnap were pluralist Idealists aren t Rudolph Carnap Carnap was one of many important logical positivists in Germany and Austria He moved to the States in 1935, started writing in English, and continued to be influential after the Vienna Circle died Carnap s pluralism The Logical Structure of the World, 1928 Carnap s detailed version of phenomenalism When I developed the system of the Aufbau, it actually did not mat- ter to me which of the various forms of philosophical language I used, because to me they were merely modes of speech, and not formulations of positions The system of concepts was constructed on a phenomenalistic basis However, I indicated also the possibility of constructin ga total system of concepts on a physicalistic basis The main motivation for my choice of a phenomenalistic basis was the intention to represent not only the logical relations among the concepts but also the equally important epistemological relations The system was intended to give, though not a description, still a rational reconstruction of the actual process of the formation of con- cepts The ontological theses of the traditional doctrines of either phenomenalism or materialism remained for me entirely out of consideration Rudolph Carnap, Intellectual Autobiography, in P Schilpp, ed, The Philosophy of Rudolf Carnap, La Salle: Open Court, 1963, p 18 Der Logische Aufbau der Welt On reading Russell s Our Knowledge of the External World: I felt as if this appeal [for scientific philosophy] had been directed to me personally To work in this spirit would be my task from now on! Rudolph Carnap, Intellectual Autobiography, in P Schilpp, ed, The Philosophy of Rudolf Carnap, La Salle: Open Court, 1963, p 13 Even though the subjective origin of all knowledge lies in the contents of experience and their connections, it is still possible, as the constructional system will show, to advance to an intersubjective, objective world world, which can be conceptually comprehended and which is the same for all observers Rudolph Carnap, Der Logische Aufbau der Welt Leipzig: Felix Meiner Verlag, 1928 English translation by Rolf A George, 1967, section 2 Components of the reductionist system of the Aufbau Primary world (Wittgenstein s terminology): sensations ( the given ), with a single (!) primitive relation of similarity not the same for all observers Secondary world: objects in physical space, with a variety of qualities Other worlds: eg other minds, social systems but which of these comes first is unimportant! Rudolph Carnap, Der Logische Aufbau der Welt Leipzig: Felix Meiner Verlag, 1928 English translation by Rolf A George, 1967 intersubjective: agreed by all subjective viewpoints

5 Starting points of the Aufbau In the initial stages of the construction, Carnap mostly replaces Russell s assumptions and definitions with rules about logical form eg, visual space is the only 5-dimensional part of our sensations (p 130) and sonic space is the only two-dimensional part Other minds are constructed without assuming that their experiences are like mine, except in their logical structure What s the point of the Aufbau? In the neo-kantian tradition the immediate data of sense do not, by themselves, constitute objective knowledge at all The point of proceeding from the data of sense via logical construction to our scientific knowledge is not, therefore, to transfer the epistemic status of the former to the latter, but rather to embed the data of sense in an objective logicomathematical structure so that they themselves become objective In the first tradition [Russell], certainty flows, as it were, from the bottom up, whereas in the second tradition [Carnap], objectivity flows from the top down Michael Friedman, Reconsidering Logical Positivism, pp128 9 So, although Carnap s system is phenomenalist, the point is not phenomenalism but what? The point of the Aufbau 1 reduction for the sake of the unification of science Carnap took this idea from Mach (and Neurath etc) This is called the Oppenheim-Putnam thesis remember Stigler s Law 2 structural realism: It is only if all concepts are part of a single interconnected system of concepts that we can hope to do what, according to Carnap s new conception of scientific objectivity, we must do: discriminate all concepts from one another solely on the basis of their purely formal or structural properties Michael Friedman, Carnap s Aufbau Reconsidered, Nous 1987;21: , p528 Carnap took this view from Poincaré It s been popularised again recently by eg John Worrall 3 the elimination of metaphysics Carnap s metaphysical targets It s always vital to know who philosophers are reacting against, otherwise you won t understand their conclusions I will call metaphysical all those propositions which claim to represent knowledge about something which is over or beyond all experience, eg about Things in themselves, the Absolute, and such like Rudolf Carnap, Philosophy and Logical Syntax, 1935, viewed 12/2/2008 Carnap s target is no longer Scholasticism (the Aristotelian tradition) as it was for all the early modern empiricists up to and including Hume; is not what we currently call metaphysics (not all of it at least); it s the Hegelian tradition and other religiously-inspired anti-empiricist philosophies Metaphysicians pretend to teach knowledge which is at a higher level than that of empirical science From the proposition: The Principle of the world is Water we are not able to deduce any proposition asserting any perceptions or feelings or experiences whatever Rudolf Carnap, Philosophy and Logical Syntax, 1935, viewed 12/2/2008 Anti-metaphysics applied to itself Any anti-metaphysical philosophy can be criticised on the grounds that it itself is metaphysical Carnap considers the objection that the laws of logic and probability are metaphysical An answer to this objection is given by Wittgenstein He replies by agreeing with it I, as well as my friends in the Vienna Circle, owe much to Wittgenstein But on the point just mentioned I cannot agree with him In the first place he seems to me to be inconsistent in what he does He tells us that one cannot state philosophical propositions and that whereof one cannot speak, thereof one must be silent; and then instead of keeping silent, he writes a whole philosophical book I do not include in metaphysics those theories whose object is to arrange the most general propositions of the various regions of scientific knowledge in a well-ordered system; such theories belong actually to the field of empirical science however daring they may be Rudolf Carnap, Philosophy and Logical Syntax, 1935, viewed 12/2/2008