A problem for a posteriori essentialism concerning natural kinds

Transcription

1 JOBNAME: No Job Name PAGE: SESS: OUTPUT: Tue Jul :: 00 /v0/blackwell/journals/anal_v_i/anal_0-0 0 A problem f a posterii essentialism concerning natural kinds E. J. Lowe There is a widespread assumption that the classical wk in philosophical semantics of Saul Kripke () and Hilary Putnam () has taught us that the essences of natural kinds of substances, such as water and gold, are discoverable only a posterii by scientific investigation. It is such investigation, thus, that has supposedly revealed to us that it is an essential property of water that it is composed of H O molecules. This is the way in which Scott Soames, in a recent paper, makes the point in the case of water and H O: [Here is] how a Kripkean explanation of the necessary a posteriity of [ Water = H O ] would go at any rate my version of it. The account holds that water is a non-descriptive, directly-referential term designating a substance where substances are taken to be physically constitutive kinds (instances of which share the same basic physical constitution). It is further assumed that a kind of this st may have different instances in different wld-states, and that if a and b are kinds with the same instances in all possible wld-states, then a is b. These are clearly metaphysical assumptions, to which we add the natural collary that f any substance, s, if, in some possible wld-state, instances of s have a certain molecular structure, then instances of s have that structure in every wld-state. In other wds, we assume that it is an essential property of a substance that instances of it have the molecular structure they do. From this it follows that [ Water = H O ] is necessary if true, and that H O which I take to be equivalent to the substance instances of which have a molecular structure with two hydrogen atoms and one oxygen atom is a rigid designat. Being true, [ Water = H O ] is, therefe, necessary. Since knowing the proposition it expresses requires knowing of a certain substance that its instances have a particular chemical structure, [ Water = H O ] is knowable only a posterii. (Soames 00: ) What Soames is saying on behalf of Kripke amounts, it seems, to this. Suppose we assume, as seems entirely uncontroversial, that the only way in which we can discover the actual molecular composition of chemical substances is by empirical scientific investigation this being the way in which we have discovered, in the case of water, that it is actually composed of H O molecules. And suppose we further assume that any chemical Analysis., October 00, pp.. E. J. Lowe

2 JOBNAME: No Job Name PAGE: SESS: OUTPUT: Tue Jul :: 00 /v0/blackwell/journals/anal_v_i/anal_0-0_ 0 a problem f a posterii essentialism 0 substance s actual molecular composition is essential to it so that, in the case of water, it is essential f it to be composed of H O molecules. Then given the semantic infmation that water is a non-descriptive, directly referential term and that H O is synonymous with the definite description the substance instances of which have a molecular structure with two hydrogen atoms and one oxygen atom we can conclude that the sentence Water is H O expresses () a truth knowable only a posterii and () a necessary truth. () follows simply from our assumption that we can discover the actual molecular composition of chemical substances only by empirical means and that in the case of water the molecular structure in question is H O. () follows from our further assumption that water, being actually composed of H O molecules, is essentially composed of such molecules and hence that water is composed of H O molecules in every possible wld in which it exists. Note that Soames is not supposing that we know only a posterii that, quite generally, any chemical substance s actual molecular composition is essential to it. It seems, on the contrary, that he takes this general truth to be known a prii. Recall that he says, in the passage quoted above, that we assume that it is an essential property of a substance that instances of it have the molecular structure they do (my emphasis) and he makes it clear that he regards the assumption in question as being a metaphysical one. What, apparently, he takes to be knowable only a posterii is, f example, that water is essentially composed of H O molecules a truth about the essence of a particular chemical substance. However, an imptant doubt can be raised at this point. It may be doubted whether, in a properly wked-out logic of essence, inferences of the following fm are valid. (Note that my preference here f the locution it is part of the essence of x that rather than it is essential of/f/to x that is a purely stylistic one. R below is a place-holder f any suitable relational expression and F is a place-holder f any suitable predicate.) () It is part of the essence of x that x is R to the actual F. () The actual F is a. Therefe, () it is part of the essence of x that x is R to a. F instance, it may be doubted whether the following instance of the fegoing schema is valid: (a) It is part of John s essence that he is the son of his actual father. (a) John s actual father is Fred. Therefe,

3 JOBNAME: No Job Name PAGE: 0 SESS: OUTPUT: Tue Jul :: 00 /v0/blackwell/journals/anal_v_i/anal_0-0_ 0 e. j. lowe 0 (a) it is part of John s essence that he is the son of Fred. (a) might be deemed true on the grounds that it is part of the general essence of any man and thus part of John s general essence, since John is a man that he is the son of his actual father, with the implication that John, just like any other man, could not have had a different father from his actual one. But (a) might be rejected because it implies that it is part of John s individual essence that he is the son of this particular other man, Fred, making one man depend f his identity on another man. One problem with that, of course, is that, given that every man must have a father and that no man can be his own father, every man would have to depend f his identity on another man, seemingly generating an infinite regress of identity-dependence. On the other hand, if some man did not have a father Adam, perhaps the strange implication would be that he, unlike other men, was exempted from such identity-dependence. It is me intelligible, surely, to suppose that if one man can be thus exempted, all men are. (I am assuming here it would still be true of Adam, albeit only vacuously, that it is part of his essence that he is the son of his actual father vacuously because, we are supposing, Adam s actual father has no designation, with the consequence that in his case, unlike John s, no true premiss cresponding to (a) is available. That Adam doesn t differ from John in respect of his general essence seems perfectly unexceptionable: after all, it can be just as true of Adam as it is of John that he couldn t have had a different father from his actual one, f this doesn t imply that Adam did actually have a father. F me on the notion of identity-dependence, see Lowe :.) In any case, whether not one finds (a) acceptable, it must be questionable whether it follows from (a) and (a), because if that were not questionable, no one who accepts (a) and (a) ought to have any qualms at all about accepting (a). And yet it seems reasonable f such a person to have such qualms. However, if the fegoing pattern of inference is invalid, then there is a crucial lacuna in the line of reasoning that is being attributed by Soames quite crectly, I think to Kripke. F now we can also question the following inference: (b) It is part of water s essence that it has its actual molecular composition. (b) The actual molecular composition of water is the H O one. Therefe, (b) it is part of water s essence that it has the H O molecular composition.

4 JOBNAME: No Job Name PAGE: SESS: OUTPUT: Tue Jul :: 00 /v0/blackwell/journals/anal_v_i/anal_0-0_ 0 a problem f a posterii essentialism 0 Again the point can be made that (b) might be deemed true on the grounds that it is part of the general essence of any chemical substance and thus part of water s general essence, since water is a chemical substance that it has the molecular composition that it actually has, with the implication that it could not have had a different one. Perhaps this is indeed something that can be known a prii, by reflection on the concept of a chemical substance. But, unless the crucial pattern of inference is a valid one which we have seen reason to doubt it will not follow from the truth of (b) and the a posterii truth (b) that (b) is true. It will not follow, that is to say, that water is essentially composed of H O molecules and hence it will not follow that water has an individual essence that is discoverable only a posterii. I should remark that in speaking as I do above of a logic of essence, I mean to distance myself from those philosophers who think that all talk of essence can be expressed in terms of a pri notion of metaphysical necessity. In this regard my sympathies lie entirely with the view of the relationship between the notions of essence and necessity that has been developed by Kit Fine (in, f instance, Fine ). Of course, it seems safe to say that neither Kripke n Soames shares that view. As a consequence, they and those who think like them on this matter may not be particularly susceptible to the st of doubt that I have raised concerning the inferenceschema that is now in question. But since I think that they are mistaken in not sharing that view, I also think that they would be mistaken in dismissing this st of doubt. In other wds, it may be that the doubt that I have raised can only have much purchase on someone who already shares the view that the notion of essence is not dependent on that of metaphysical necessity, conceived as truth in all possible wlds. But to the extent that this can be defended as the crect view as I, of course, believe it can the doubt is one that ought to be taken seriously by all who are attracted, on the basis of Kripke s wk, to a posterii essentialism concerning natural kinds. One reason why the remarks of the preceding paragraph are pertinent is this. Someone who thinks that the notion of essence is to be explained in terms of a pri notion of metaphysical necessity is very likely to be of the opinion that our iginal inference-schema can be reduced to something like the following (where necessary means metaphysically necessary ): (*) It is necessary that, if x exists, then x is R to the actual F. (*) The actual F is a. Therefe, (*) it is necessary that, if x exists, then x is R to a.

5 JOBNAME: No Job Name PAGE: SESS: OUTPUT: Tue Jul :: 00 /v0/blackwell/journals/anal_v_i/anal_0-0_ 0 0 e. j. lowe 0 Such a person will probably then point out that the actual F isarigid designat, so that if a is also a rigid designat, (*), if true, expresses a necessary truth and we ought to be able to substitute a f the actual F in (*), salva veritate, to give (*). Thus, such a person will say, on the assumption that a proper name, such as Fred, is a rigid designat, we certainly ought to acknowledge the validity of the inference from (a) and (a) to (a). Hence, such a person will conclude, my attempt to call into question the validity of the latter inference must be mistaken. To this line of thought my reply is that it is wrong to suppose that our iginal inference-schema can be reduced to the fegoing one, because the notion of essence is pri to, and so not reducible to, that of metaphysical necessity. Hence, we should not let our thoughts about the logic of essence be guided by presuppositions concerning the logic of metaphysical necessity. What our example involving John and Fred shows is that, in fact, it is highly questionable whether the actual F and an actually co-designative proper name a are inter-substitutable, salva veritate, within the scope of the sentential operat it is part of the essence of x that whatever may be the case with the operat it is necessary that. To this it may now be replied that, even if our first inference-schema, involving an essence operat, is not valid, we have done nothing to show that the second one, involving a necessity operat, is not valid and that its validity would provide us with enough to show, at least, that there can be cases of necessary a posterii truths, one of these plausibly being that necessarily, if water exists, it has the H O molecular composition, just as Kripke claimed. However, if it is conceded as I believe it ought to be not only that the notion of metaphysical necessity is not pri to that of essence, but also, on the contrary, that the notion of essence is pri to that of metaphysical necessity, then it should be conceded that, ultimately, we ought to be guided in our views about the logic of necessity by a properly wked-out logic of essence: something that, unftunately, we don t yet have. Consequently, I am not prepared simply to take it on trust that the second inference-schema, involving a necessity operat, is valid, just because current thodoxy in modal logic would have it so. That thodoxy is sustained, of course, by the possible-wlds model of modal truth and, construed in the light of that model, our second inference-schema may indeed appear compelling. However, a they of metaphysical necessity which represents necessary truths as being grounded in truths about essence is antithetical to the possible-wlds model of modal truth and hence can and should resist drawing any conclusions from modal intuitions based on that model. Note, in this connection, that the inclination to maintain that a true sentence of the fm The actual F is a, where a is a proper name, expresses a necessary truth that, f example, John s actual father is

6 JOBNAME: No Job Name PAGE: SESS: OUTPUT: Tue Jul :: 00 /v0/blackwell/journals/anal_v_i/anal_0-0_ 0 a problem f a posterii essentialism 0 Fred, if true, expresses a necessary truth entirely dissipates in the absence of a presumption that the possible-wlds model of modal truth is crect. Befe that model became prevalent, it seems safe to say, no philosopher would have been in the least inclined to say that this sentence, if true, expresses a necessary truth. The alleged necessity, if it is true, of the proposition that it expresses is, I suggest, entirely an artefact of the possible-wlds model of modal truth. Since, however, the claim that our second-inference schema is valid presupposes that its second premiss, (*), if true, expresses a necessary truth, to the extent that this presupposition is questionable f the fegoing reason, so too is the validity of that inference-schema. Let me sum up. If Soames is right, the key contribution of Kripke to the metaphysics of essence was to show how, by combining a prii knowledge of general essential truths with a posterii knowledge of particular actual facts, we could generate instances of particular essential truths that are knowable only a posterii. However, what I hope I have just shown is that this line of reasoning depends upon an inferencepattern in the logic of essence whose validity is, at the very least, open to doubt. Kripke s conclusion, when it first became known, was regarded as remarkable and imptant, and it has since come to be accepted by a great many philosophers, almost without question. But given the remarkable nature of the conclusion, and the fact that it is the product of a relatively straightfward line of reasoning, perhaps we should have been me suspicious from the start that something was questionable in the reasoning. My strong suspicion is that we ought to question the crucial inference-pattern identified above. Perhaps we should hold, after all, that all essential truths are knowable a prii if they are knowable at all. Perhaps, furtherme, we ought to wonder whether particular substances, such as John and water, really have individual essences, in addition to general ones. Department of Philosophy Durham University 0 Old Elvet Durham DH HN, UK E.J.Lowe@durham.ac.uk References Fine, K.. Essence and modality. In Philosophical Perspectives, : Logic and Language, ed. J. E. Tomberlin. Atascadero, CA: Ridgeview. Kripke, S.. Naming and Necessity. Oxfd: Blackwell. Lowe, E. J.. The Possibility of Metaphysics: Substance, Identity, and Time. Oxfd: Clarendon Press.

7 JOBNAME: No Job Name PAGE: SESS: OUTPUT: Tue Jul :: 00 /v0/blackwell/journals/anal_v_i/anal_0-0_ anthony hatzimoysis Putnam, H.. The meaning of meaning. In his Mind, Language and Reality: Philosophical Papers, Vol.. Cambridge: Cambridge University Press. Soames, S. 00. The substance and significance of the dispute over twodimensionalism. Philosophical Books :. 0 The case against unconscious emotions Anthony Hatzimoysis. Talk of the unconscious in the philosophy of emotions concerns two things. It can refer to an emotion whose existence is not in any way present to consciousness. Or, it can refer to emotional phenomena whose meaning lies in the unconscious. My interest here is in the fmer issue of whether emotional states can exceed the reach of conscious awareness. I start with a presentation of psychoanalytic views that infm contempary wk toward a cognitivist analysis of emotion. The discussion of cognitivism leads to a consideration of wk in experimental psychology that appears to establish the reality of emotional phenomena that transcend conscious awareness. However, I argue that a careful consideration of the relevant evidence falls sht of suppting the claim that there are unconscious emotions.. One can build a case f the possibility of unconscious emotions by trying to extend the psychoanalytic view of the unconscious so as to include emotional states. Let us assume that there is no a prii stricture on what can fall in the categy of the unconscious. What makes something unconscious is the process of repression by which that thing moves out of conscious awareness and is kept there. Given the psychological power of intense recalcitrant emotions it is only natural to think that emotions would be among the primary targets of repression. Ordinary experience seems to lend suppt to this view. We often encounter a friend who would deny that she experiences an emotion (such as anger, jealousy, sadness) that is obvious to us it suffuses every waking moment of her life. A simple explanation of that phenomenon would be that although the emotion is present in that person s experience, it is absent from her consciousness in other wds, it is an unconscious emotion.

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10 MARKED PROOF Please crect and return this set Please use the proof crection marks shown below f all alterations and crections. If you wish to return your proof by fax you should ensure that all amendments are written clearly in dark ink and are made well within the page margins. Instruction to printer Leave unchanged Insert in text the matter indicated in the margin Delete Substitute character substitute part of one me wd(s) Change to italics Change to capitals Change to small capitals Change to bold type Change to bold italic Change to lower case Change italic to upright type Change bold to non-bold type Insert superi character Insert inferi character Insert full stop Insert comma Insert single quotation marks Textual mark under matter to remain through single character, rule underline through all characters to be deleted through letter through characters Encircle matter to be changed through character where required Marginal mark New matter followed by new character new characters under character e.g. over character e.g. and/ Insert double quotation marks and/ Insert hyphen Start new paragraph No new paragraph Transpose Close up linking characters Insert substitute space between characters wds through character where required Reduce space between characters wds between characters wds affected