segunda-feira, 23 de maio de 2016




I am full professor at the UFRN (Brazil) and researcher for the CNPq. My graduation was in medicine. I made my PhD in Germany and post-doctoral sabbaticals of one year in München (with Friedo Ricken), Konstanz (with Wolfgang Spohn), Oxford (with Richard Swinburne), Berkeley (with John Searle) and now in Göteborg (with Anna-Sofia Morin). I Published some papers in international journals and two books in English: The Philosophical Inquiry: Towards a Global Account  (UPA, 2002), developing a theory on the nature of philosophy, and Lines of Thought: Rethinking Philosophical Assumptions (CSP, 2014), which is a collection of papers on central issues of contemporary philosophy. Presently I am working in a book to be called  Philosophical Semantics: Towards a New Orthodoxy (CSP, 2016) aiming to defend some old ideas of the philosophy of language, which I believe are important an were falsely debunked by the philosophy of language of the last 60 years.

Photo of Magda's tree

Minha poesia é tão hipermoderna que só daqui a mil anos, quando a espécie humana se alçar ao nível ômega, ela será capaz de compreendê-la!  Quanto à minha filosofia, essa então nem se fala. Essa vai até o osso. Sua força é como a da explosão de uma supernova. Ela é tão profunda, tão profunda mesmo, que espécimes do gênero humano, especialmente aqueles por muitos anos adestrados na miopia do academicismo cientificista da pigmeica filosofia contemporânea não conseguirão enxergar dela mais do que traços embaçados.
Por isso, ao temerário que pretender imergir em sua profundidade abissal eu previno: muito dificilmente conseguirá retornar outra vez à superfície sem explodir pelo simples efeito da despressurização cognitiva. Pois a distância entre a minha filosofia galáctica e quase toda a minúscula filosofia de nossa época é tão grande que não se mede em quilômetros, nem em léguas, nem em milhas... mas em anos-luz! Por isso resolvi denominá-la "filosofia clássica pós-analítica e anti-contemporânea."

# MODAL ILUSIONS (against transepistemic metaphysical identities)


Appendix to Chapter 2


Philosophy unravels the knots in our thinking; hence its results must be simple, but its activity is as complicated as the knots that it unravels.

Saul Kripke’s philosophical application of modal logic to the problems of reference seems to me to be burdened by a disturbing web of confusion. Since many disagree, I will try to justify myself through a critical discussion of his article ‘Identity and Necessity’,[1] which precedes the more developed views defended in his book Naming and Necessity,[2] since that short article takes some fundamental ideas direct from the oven. Paragraphs summarising the article by Kripke are printed in italics, to be distinguished from paragraphs containing my own comments. To my coments on his ideas I will add short criticisms of some central externalist views from Hilary Putnam, Tyler Burge and others, as part of my project of debunking the metaphysics of meaning.

Kripke begins by considering a modal argument for the necessity of statements of identity. Where is the operator of necessity, which here will be seen as de re (regardless of the mode of linguistic designation), we can consider that, given the principle of substitutivity of identicals, according to which ‘(x) (y) ((x = y) → (Fx → Fy))’, and given the principle of identity, according to which ‘(x) (x = x)’, we can conclude that if the property F is to be necessarily applied to x, then y must also have this property, i.e. it is necessary that y equals x; in symbolic notation, (x) (y) (x = y) → ((x = x) → (x = y))’, namely: ‘(x) (y) (x = y) → (x = y)’.
   This understandable result leads Kripke to the bold conclusion that, as long as there are theoretical (essential) identities, identities between names are necessary. We know that by universal instantiation ‘□(x = y) → □ (a = b)’. That is, if a and b are real names and ‘a = b’ is a true identity, then this identity is necessarily true. This would be the case for identities like ‘Hesperus is (the same as) Phosphorus’ and ‘Cicero is (the same as) Tulius’: they must be necessary. Further, if F and G are theoretical predicates, defined as essential designators of properties, if they form a true theoretical identity of the form (x) (Fx = Gx), then this identity is necessarily true. That is why identities like ‘Heat is molecular motion’ and ‘A state of mind is a physical state’, if true, are necessary.
   Kripke recognises that identities between names and theoretical identities have generally been considered contingent, and presents the reasons for it. Consider the statement ‘Hesperus is Phosphorus’. Since Hesperus is Venus seen at dusk (Evening Star), and Phosphorus is Venus seen at dawn (Morning Star), it was an important astronomical discovery that they are actually the same planet, as Frege has noted. Therefore, this seems not to be a necessary, but rather a contingent empirical truth. The same applies to theoretical identities such as ‘Heat is molecular motion’. This identity was a discovery of science and could be false, because if caloric theory (the theory that heat consists of a self-repellent fluid called caloric) were correct, heat wouldn’t be molecular motion. This seems to be a clearly contingent statement, since it could be otherwise.
   Kripke’s thesis, however, is that contrary to the appearances, all these identities, although have been learned a posteriori, are necessary, even if they do not seem to be. To reinforce his thesis he introduces an important distinction between the rigid designator, here defined as a term that refers to the same object in all possible worlds in which this object exists, and the non-rigid or accidental designator, which can refer to different objects in distinct possible worlds. Proper names and terms of natural species, at least, are rigid designators, while definite descriptions are accidental designators. Hence, if we have an identity a = b and the identity symbol is flanked by proper names, this identity is necessarily true if true at all.

It seems clear that a mathematical term can be seen as a rigid designator, insofar as it does not depend on how the world is; but could our empirical proper names not be rigid designators? In the attempt to show that they could be accidental designators, we can imagine that it were discovered that soon after the birth of G. W. Bush an extra-terrestrial creature possessed his body, and since then has lived in it and maintained his identity, becoming in this way the President of the United States and performing all actions attributed to him. Would not in this case the proper name ‘G. W. Bush’ be used to refer to this extra-terrestrial creature instead of the son of Barbara and George Bush, being im this way an accidental designator?
   I think that the idea that the proper name is a rigid designator would resist to this objection. According to Kripke’s theory, the reference of a proper name is determined by an act of baptism, so that the true W. G. Bush, a rigid designator, would have since long disappeared. On the other hand, a homonymous being, the embodied extraterrestrial being, whose true name is Qfwfq, would have had in some day a baptism and the name W. G. Bush, as a nickname of Qfwfq, would apply to the same extraterrestrial being in each possible world where it would exist, being therefore also a rigid designator.
   Furthermore, using my own theory of proper names summarized in the Appendix of chapter 1, the result would be the same. According to this theory the referent of a proper name is the object that satisfies the identification rule for the application of the proper name. And what this identification rule requires is a sufficient and better than any other satisfaction of the disjunction of the fundamental description-rules, which are the localizing and the characterizing rules. For the adult W. G. Bush (Qfwfq), for instance, the localizing description includes his spatio-temporal career on the earth and after its Bush-embodiment and in the planet Omega before it, while the characterizing description would include his deeds, as his election as the 43tr president from USA, who make wars in Irak and Afganistan, and the person who earlier in the planet Ômega has make the deeds of Qfwfq... In every possible world were this identification rule is satisfied, W. G. Bush (Qfwfq) would exist. Hence, the identification rule for the name is a rigid designator for us too.
   Something very different, however, is the idea that the concept of rigid designator has the consequences that Kripke expected as a way to ensure the existence of de re metaphysical necessities of identities between our usual proper names or between terms of natural species. Kripke believes to have warranted the necessity of this identity by having discovered a radical difference of nature between proper names, on the one hand, and definite descriptions, on the other. What his words suggest is that a proper name would reach its reference without intermediaries, with help of a direct (in my view purely magic) relation instaured in the act of baptism, which does not really depend on any property of the object, allowing then the production of an external causal chain that in the end reach each speaker of the name really referring to its bearer. A definite description, on the other hand, is only an accidental designator: it would refer to different objects in different possible worlds, probably because it has what Stuart Mill called ‘conotation’, by means of which it refers to proprieties that can be present in the object or not. Using Kripke’s example, this would be the case of the description ‘the inventor of the bifocals’, a description who refers to Benjamin Franklin in our world, but that could refer to any other person or have no reference in different possible worlds.
   I think that this strange dichotomy, suggesting a mysterious difference in the nature of reference is totally dispensable if we use my own neodescriptivist theory of proper names, since this theory gives a non-misterious reason why proper names are rigid designators and definite descriptions are accidental (see Appendix of chapter 1). In this way I agree with the idea that the necessity of the rigid designator is always de dicto, supporting the view according to which the de re necessity is only a sub-class of de dicto necessity, without any metaphysical import.[3]
   The neodescriptivism I propose makes a proper name a rigid designator because any combination of descriptions that allows its reference in accordance with its identification rule must be satisfied in all any worlds in which the proper name has a bearer, simply because the identification rule simply defines what its bear can be. Moreover, two proper names of the same object will, as rigid designators, identify the same object in any possible world since their identification rules must identify the same object; but they usually do it under different guises, under different ways of presentation, simply because they emphazise different perspectives in which different descriptions or groups of descriptions are satisfied. So, even being rigid designators referring to the same object in any possible world, since the identifying criteria can differ, it may be an empirical matter to decide if two different rigid designators are referring to the same object or to two different objects, being the identitity sentence at first contingent a posteriori. The exception is when we finally establish by convention that they are constituents of the same rigid designator, building for this a more complex identification rule that includes both. But in this case the identity will be necessary a priori.
   This is a way to express Frege’s insight according to which ‘Afla = Ateb’, in which Afla is the same mountain as Ateb, but explored from a different complementary perspective, what gives to these names different but complementary senses or modes of presentation. Since for Frege references are dependent on senses, the proper names ‘Afla’ and ‘Ateb’ are de dicto rigid designators and not metaphysically de re rigid designators. For those who know that Afla is Ateb the more complete identity sentence would have the form ‘Afla [-Ateb] = Ateb [-Afla]’, that is, something in the identification rules of Afla and Ateb must make clear that they are identifying numerically the same object.

Kripke also considers the problem of apriority. A priori truths are those that we can know without appealing to experience. Many consider the necessary and the a priori to be equivalent. But the concept of necessity is according to him metaphysical about how the world must be – while the concept of a priori is epistemic – about how we know the world. Kripke thinks that the two classes are not equivalent. Consider, he writes, Goldbach’s conjecture, which states that any natural number above two is the sum of two primes. It may be a necessary truth without our knowing it a priori!

The suggestion that necessity is metaphysical while apriority is epistemological is highly questionable. This distinction is justified only if there are metaphysical de re necessities, as Kripke intends, since a de dicto necessity would follow from a banal epistemologic apriority. However, the existence of metaphysical de re necessities in the supposed sense would be something that escapes our cognitive faculties, since our empirical knowledge is inherently fallible. All that we can do is to postulate empirical necessities, for instance, by accepting well-entrenched and strongly inductively grounded natural laws. To really know if there is the necessity of a natural law beyond this mere postulation (pace Armstrong) would require absolute knowledge – something that our epistemic falibility makes impossible. Therefore, the necessities of natural laws is nothing but a result of our well grounded decision to treat them as necessities. However, based on firm experience, this necessity is always postulated by us and then turned out into a rule of our conceptual system. Wittgenstein would call them ‘grammatical rules,’ like the rules grounding some linguistic practice.[4] Here is his suggestion, in which we read the word ‘rule’ involving a priori propositions:

Every empirical proposition can serve as a rule if it is fixed as the unmovable part of a mechanism, in such a way that the entire representation revolves around it, making it part of a system of coordinates independent of the facts.[5]

To illustrate what I mean, consider the statement of some particular physical law, for instance, Einstein’s famous ‘e = mc2.’ It can be doubly understood:

(a)  As a component of the theory of general relativity, under the assumption of the truth of this theory. In this case, it will be seen as necessary a priori, that is, as a kind of postulate independent of experience: its necessity is conventionally postulated (we could say with Wittgenstein that the statement is treated as the inmovable part of a mechanism).
(b)     As a mere element of our ever possibly changing overall system of beliefs. Hier, however, the same physical law should be considered as an a posteriori contingent statement. After all, in principle it could be falsified by observation, assuming that fallibility is a pervasive trait of our empirical knowledge (with Wittgenstein we say here that the truth of the statement is treated as dependent of the given facts).[6]

Attention to this two ways of considering a statement can lead us to suggest that a statement as (i) ‘Heat is (constituted of) molecular motion’ can be read in two ways: (a) as a necessary a priori statement – if read as a piece of the subsystem of beliefs that constitutes the thermodynamics, assuming the truth of this subsystem. In this case (i) means (ii) ‘Heat in gazes is (constituted of) molecular motion [under the assumption of the truth of the thermodynamics]’. But (i) can also be read as (b): a contingent a posteriori statement, if understood in its relation to our ever changing overall system of beliefs. In this case (i) means (iii): ‘Heat in gazes is (constituted of) molecular motion [according to what we have found until now…]’. If it is so, then it is easy to conclude that by suggesting that the statement ‘Heat is molecular motion’ is necessary a posteriori Kripke was simply combining the necessity of the (a) reading with the aposteriority of the (b) reading of the statement (i).  
   As for Goldbach’s conjecture, the fact that it may be a necessary truth without our being aware of it does not mean that its necessity is a posteriori, as Kripke supposes. If someone finds a proof of this conjecture, giving to it the status of a theorem, it will be shown to have an a priori necessity. The fact that we presently don’t know it a priori does not show that it is a posteriori.

Maybe the most stricking example of a necessary a posteriori statement introduced by Kripke is that of the wooden table in front of him. It starts with the question: could it have consisted since the beginning of its existence of ice from the Thames? Certainly not: It would be a different object. Thus, the statement ‘This table, if it exists, cannot be made of ice,’ is a necessary truth known a posteriori. Tables, he says, are usually not made of ice. This table seems to be made of wood, and it is not cold. Hence, it is probably not made of ice. Of course, this could be a delusion. It could actually be made of ice. But that’s not the point, says Kripke. The point is that given the fact that the table is not made of ice, but of wood, one cannot imagine that it could be made of ice. Given the fact that it is not made of ice, he concludes, it is necessary that it is not made of ice. In other words: being P = ‘This table is not made of ice’, we know a priori the truth of ‘If P then P’. Moreover, he says, we know from empirical research that P is true. Combining these two statements, he constructs the following argument applying a modus ponens:

     1 P □P
     2 P
     3 □P

It is therefore necessary that the table is not made of ice, although this is only known a posteriori, by empirical research. The statement; ‘This table is not made of ice’ is necessary a posteriori.

The obvious difficulty with Kripke’s argument concerns the epistemological status of P in the second premise. In the second premise, the truth of P is affirmed in the desconsideration of the fact that P, as any empirical statement, can only be known and considered as true by inevitably fallible epistemic subjects. But if it is so P can be false. Hence, the statement P of the second premise should be more precisely written as (2’): ‘It is practically certain (that is, it is extremely likely, so that we can assign to it a probability very near to 1) that P (i.e., that this table isn’t made of ice).’ Indeed, it must be so, because only God – the infallible and omniscient epistemic subject – could know with absolute certainty the truth of the statement P (that is, would be able to assign it the probability 1). God could know for sure the factual existence of P, in this way giving to the affirmation of P a truly metaphysically de re necessity. Unfortunately, we cannot appeal to God in this matters. Hence, all that we can know is that P is practically certain in the already pointed sense of being extremely likely to be true. This must be so, since our empirical knowledge is never absolute (it is always possible, for instance, that for some reason I believe I am standing before a hard wooden table, although it is actually made of ice, as Kripke himself admits).
   Assuming this, consider now the first premise. The same cannot be said of it, since it is a conditional. It is acceptable that given the fact that P – or, more precisely, if the fact that P is really given – then it follows that P is necessary. So, what P → P says is (1) ‘If it is really the case that P, then it is necessary that P,’ and this is a logical truth. But what this show is that P implies □P only possible if the truth of P is absolutely certain, for instance, knowable by God’s omniscience. Hence, the most complete analysis of premise (1) would be (1’): ‘If it is absolutely certain that P (if P has the probability 1), then it is necessary that P’, but surely not as (1’’) ‘If it is practically certain that P (that is, if P has a probability near to 1), then P is necessary,’ for the mere probability of P, no matter how high, if less than 1, would not warrant the necessity of P. Admitting the changes of premise (1) to (1’) and (2) to (2’), Kripke’s argument can be made more explicit as saying:

1’. If it is absolutely certain that P, then it is necessary that P.
2’. It is practically certain that P.
3’. It is necessary that P.

This argument is obviously non-valid, since the modus ponens cannot be applied to (1’) and (2’) in order to give us (3). And the reason is that the antecedent of (1’) does not say precisely the same thing as (2’), what makes the argument equivocal, hence fallacious. We conclude that under a better scrutiny Kripke’s argument does nothing to convince us that we can know that the utterance ‘This table is not made of ice’ is metaphysically necessary or necessary a posteriori.
   A valid but trivial argument without the kind of distortion that leads to Kripke’s equivocal conclusion would be the following:

1.  If it is practically certain that this table is made of wood, then it is practically certain that it is not made of ice.
2.  It is practically certain that this table is made of wood.
3.  It is practically certain that this table isn’t made of ice.

As the first premise is a necessary and a priori statement, while the second premise is a contingent a posteriori statement (since we can only by experience be practically sure that the table is made of wood), the conclusion must inherit, as a rule, the the weakest properties of the premises: it is contingent a posteriori.
   Now the reason for Kripke’s misleading idea that the conclusion of his own argument must be necessary a posteriori becomes obvious: in the conclusion he confuses the necessity of the first premise (1’) with the aposteriority of the second (2’).

Another case of the necessary a posteriori is, according to Kripke, the identity between proper names such as ‘Hesperus is Phosphorus’ and ‘Cicero is Tulio.’ These are empirical identities, generally considered contingent. For Kripke they are identities between rigid designators, which make them necessary, since in the most diverse possible worlds these names will refer to the same object, a situation not possible where Hesperus isn’t Phosphorus or Cicero isn’t Tulio. We could, he says, have identified Hesperus and Phosphorus with two different celestial bodies, but in this case the sentence ‘Hesperus is Phosphorus’ would have a different meaning. This would be the case, for example, if Martians had once populated the earth and had identified Hesperus with Venus and Phosphorus with Mars. Similarly, ‘2 + 2 = 4’ would be false if by 4 we understood the square root of -1. The same is true with the identity ‘Cicero is Tulio.’ According to him it seems that this statement is contingent because sometimes we learn these names with the help of definite descriptions, like ‘the greatest Roman orator,’ which are accidental designators, thinking that we identify the object through properties, when in fact such names are not synonymous with descriptions, but rather with rigid designators.

These examples of a posteriori necessities are also contestable.
1. Concerning the statement ‘Hesperus is Phosphorus’ we need consider its analysis according to the identification rules of our metadescriptivist theory of reference for proper names. For ‘Venus’ we have an identification rule demanding:

(i): the sufficient and predominant satisfaction of a localizing description-rule of being the second planet of the solar system as the astronomers have discovered it do be and/or the characterizing description-rule saying that it is a planet with almost the size of the earth.

What is the status of the identity ‘Hesperus is Phosphorus’? I suggest that this is ambiguous, depending on the context. In a simplified way[7] we have two cases; the first could be given for a child who in a luminous night asks the name of a star pointing to the sky. In this case we explain the the identification rules for the appearances of ‘Hesperus’ or ‘Phosphorus’:

A: For ‘Hesperus’ the identification rule is (i-a): ‘the most brilliant celestial body that appears in the down,’ and for ‘Phosphorus’ the identification rule is (i-b) ‘the most brilliant celestial body that appears in the evening.’

The rules (i-a) and (i-b) are rigid identificators, but they are rigid concerning the context of appearance of celestial bodies and nothing more: in any possible world, for instance, ‘Hesperus’ in this sense can be applied to the most brilliant celestial body appearing in the down, as ‘Phosphorus’ fot the evening.
   To get the identification ‘Hesperus = Phosphorus’ we need to add that under the astronomic context both bearers satisfy the same identification rule (i) for Venus, what will be a contingent a posteriori identification, as far as there is still no identification rule unifying (i-a) and (i-b) with (i). This was the case when the Babylonians discovered that Hesperus and Phosphorus are different appearances of the same object. In this case ‘Venus = Venus’ has descriptions like ‘the most brilliant star in the down’ as merely auxiliary descriptions.
   Now we can in the long run unite the rules building something more strong:

B: Venus is the planet that satisfies sufficiently and more than any other planet the identification rule (i), satisfying also the identification rule (ii-a), through which it is called ‘Hesperus’, and satisfying the identification rule (ii-b) through which it is called ‘Phosphorus.’

Adduming this as a rigid designator, the identification ‘Hesperus = Phosphorus’ that arises from B is a necessary a priori identity because it says that Venus is by definition the same planet that appears either as Hesperus or as Phosphorus.
   The difference between cases (A) and (B) depends on what I would like to call the context of interest. In the case (A) we do not mind with the identity or we see it as a contestable truth of our overall system of beliefs. In this case the best that we can say is:

(a)  [According to our possibly changeable overall system of beliefs it is highly probable that] not only that Hesperus is the most brilliant celestial body that appears in the evening and that Phosphorus is the most brilliant celestial body that appears in the dawn, but also according to our foundings that Hespherus = Phosphorus.

In this case the statement is read as contingent and a posteriori because it is remounts to an astronomic discovery and its identity is only probable. We are saying that there are two modes of presentation of an object and that this object is probably the same planet, namely, Venus. Calling h = Hesperus, E = the most brilliant celestial body that appears in the evening, p = Phosphorus, and D = the most brilliant celestial body that appears in the dawn, we can formalize (b) as:

a)     (Dh & Ep) & (h = p)

Contemplating the potential changeability in our beliefs as a whole, ‘Hesperus is Phosphorus’ remains a contingent and a posteriori identity. It cannot be necessary because being this identity only highly probable it is always possible that Hesperus isn’t Phosphorus: it does not belong to these two identification rules that they are unified in a same convention.
   For instance: although extremely unlikely, it is logically possible that the gods have produced a great illusion of knowledge in the human minds, and that the planets are nothing more than a swarm of fireflies that every night assemble to decorate the celestial Vault. In this case, Hesperus would have a different location than Phosphorus when seen by the naked eye, but it would look identical to Phosphorus when viewed through a telescope – not because it is the same planet or a planet at all, but as a result of an unknown kind of witchery.
    Now, there is also the way (B) to read ‘Hesperus is Phosphorus,’ which belongs to a context of interest in which the planet Venus is what really mind. Suppose that the observers are amators astronomers looking at Venus in a telescop. In this case the context of interest is centered in the the idea that the statement ‘Hesperus is Phosphorus’ means the following:

(b) [Assuming the truth of our present astronomical knowledge] Hesperus, that is, Venus as the second planet of the solar system appearing as the most brilliant in the evening = Phosphorus, that is, Venus as the second planet of the solar system appearing as the most brilliant in the down.

Under the assumption of our present astronomic views this statement is read as being necessary a priori: We are only saying that the same Venus has two different modes of presentation that it the fact that Venus is Venus is presented by means of two different sub-facts. Since we can today agree on the necessity of the identity of the reference of Hesperus and Phosphorus based on the assumption of facts and theories universally accepted by astronomers, we can simply postulate the necessity of the identity as logically derived from the assumption of the truth of these theories – here we made the identity an unmoveable piece of the mechanism. Certainly, this assumption isn’t in itself absolutely warranted, but this is a different history.
   Now, calling h = Herperus, D = the most brilliant planet of the solar system appearing in the down, v = (Venus), S = the second planet of the solar system, p = Phosphorus, and E = the most brilliant planet of the solar system appearing in the evening, we have the following formalization of what I have said:

[(Dh = Sv) & (Ep = Sv)] → (Dh = Ep)

Here the identity appears as a consequence of what is already established.
   To conclude: in my view Kripke creates his necessary a posteriori interpretation of the statement ‘Hesperus is Phosphorus’ by confusing the status of the two given interpretations. Without making any distinction he unconsciously adds the aposteriority of the interpretation (a) of the identity with the necessity of the interpretation (b) of the same identity. The lack of a more careful analysis gives us the illusory impression that something new has been discovered.
   One could produce here an argument parallel to the argument applied by Kripke to the indexical case of the table made of wood in the attempt to demonstrate the metaphysical necessity that Hesperus is the same as Phosphorus in the case (a), since these names are rigid designators that should pick up necessarily the same object in any possible world. Calling Hesperus h and Phosphorus p we can build the following Kripkian argument:

     (Dh = Ep) → (Dh = Ep)
     Dh = Ep
     (Dh = Ep)

However, here too the modus ponens does not apply because although the first premise is true, the second premise would only be able to assure us the conclusion ‘(h = p)’ if it were able to give us an absolute assurance of the truth of ‘h = p’. what is not the case. In order to establish the truth of ‘h = p’, this truth would need to be discovered, not by inevitably fallible human epistemic subjects, but only by God, the omniscient and infallible epistemic subject. Because of this, ‘h = p’ can here only be seen as an empirical supposition, saying that it is practicaly certain (extremely probable) that ‘h = p’, which is still not the same as the absolutely certain. The following formulation demonstrates again the misconception of the argument according:

       If it is absolutely certain (with probability 1) that h = p,
       then (h = p).
       It is practically certain (with probability near to 1) that h = p.
       (h = p)

   Since we are dealing with the case (a) and the absolute certainty required by the identity of the second premise is not available, the equivocity of the argument is clear. We cannot use the modus ponens to derive the a posteriori necessity of h = p.
   However, dealing with case (b) we can simply stablish that ‘Phosphorus = Hespherus’ by definition, under the assumption of our modern astronomic theories, establishes the two possibilities as derived from the identification rule for the planet Venus. In this case we do’t need the argument above. We simply assume that:  (Dh = Ep).

2. The second example given by Kripke is very different and it would be misleading to confuse it with the example above. It concerns the utterance ‘Cicero is Tulio.’ Assuming my theory of proper names, the localizing description for his identification is (shortly) ‘Born in Greece in 3.1.106 BC, died in Rom 7.12. 43 BC,’ and the characterizing description is (shortly) ‘the greatest Roman orator, a politician, lawer and philosopher.’ His whole name was ‘Marcus Tullius Cicero.’ Since the proper name does not belong to the fundamental descriptions, but to the auxiliary ones (he could receive another name in a different possible world), Kripke is only relying on the fact that not all speakers know that Cicero and Tulio are parts of a same proper name as a point of convention in our actual world, assuming that they both know who is the bearer of the fundamental descriptions implied by the name or its parts.
   As a consquence, the question is a trivial one, namely, whether the speaker knows the convention (a question not very different from the question of who knows that a triangle is the same as a trilateral figure). Hence, the right answer is that ‘Tulio is Cicero’ is necessary a priori as a linguistic definition, since there was no discovery that Tulio is Cicero, as much as there is no discovery that a triangle is a trilateral figure. Moreover, to say that the statement ‘Cicero is Tulio’ is a posteriori would be to confuse its belonging to a definition in our actual world – which is a question of being informed about conventions – with the possible names that the reference of this name could have received in different counterfactual situations, where Cicerus would not have been also called Tullius in order to build the name ‘Marcus Tullius Cicero’. But this is as trivial as to say that under a different convention the triange would not have been a trilateral figure.

3. Another kind of counterexample concerns the origin. For Kripke rigidity makes true parenthood necessary. Consider the sentence ‘Ismael Lowenstein is the son of Abel and Berta Lowenstein.’ According to a Kripkian, this statement would be necessary a posteriori because even if known a posteriori, a person with different parents, coming from a different ovulo and a different spermatozoid, would not be Ismael Lowenstein.[8] 
   However, suppose that Ismael makes the shocking discovery that his parents are not his parents; there was a mistaken change of babies in the hospital where he was born and the DNA analysis has proved that he is instead the actual son of Amanda and Mario Belinzoni. Of course, this is no decisive reason to think that Ismael has ceased to be Ismael; it is even so written in his personal identity card. If asked, he would answer that his name is Ismael Lowenstein. But concerning what matters, namely, the whole statement, with concerns the question of parenthood, the point is ambiguous. One could use as criterion of parenthood (i) those who have take care of him and nurtured him with love, and in this case the statement ‘Ismael is the son of Abel and Berta Lowenstein’ is true, even if he is originated from one spermatozoid of Mario and one ovulo of Amanda. Normaly the origin isn’t part of the characterizing description-rule of a proper name, which is a fundamental element for the identification rule of the referent. Conclusion: a statement like ‘Ismael is the son of Abel and Berta Lowenstein’ isn’t necessary a posteriori. It is contingent because it could be always false in a counterfactual situation. And it is as expected a posteriori because it depends on experience to be learned.
   However, it is possible to imagine a situation like that suggested by Kripke. Suppose that we were in the Nazi German and that Abel Lowenstein were Jewish. In this case it is possible that for the Nazis the genetic origin should be an overhelming part of the fundamental characterizing description-rule used to identify the bearer of a proper name. In this case Carlos Belinzoni would be immediately rebaptized with the name ‘Ismael Lowenstein’ and send to a concentration camp. And the liberated Ismael Lowenstein would be rebaptized with the name ‘Carlos Belinzoni.’ However, even in this more Kripkian case the statement ‘Ismael Lowenstein is the son of Abel and Berta Lowenstein’, though true, would not be a case of necessary a posteriori. The statement would remain contingent a posteriori. And it is so because its truth, based on the satisfaction of conventions, isn’t absolutely warranted. Here we have again the confusion between the absolutely certain and the practically certain. That is, one can establish as a truth by convention the rule ‘If a is generated by the parents b and c, then a is their son.’ But the application of this convention demands empirical experience, what is the cause of its practical certainty and its unavoidable contingency. (God could see this truth as necessary, but as Leibniz saw God would see any truth as necessary.)
   Worst than the necessary a posteriori is a later invention of Kripke called contingent a priori. It is the case involving the platinum rode in Paris that once defined the meter as the unity of length. According to him the definition of ‘one meter’ as ‘the lenght of S at to’ was a priori, but contingent, since ‘one meter’ is a rigid designator and ‘the length of S at to’, being a description, is an accidental designator, making the lengh possibly langer or shorter than one metter, for instance, by earlier heating or cooling. Therefore, the statement ‘Paris platinum rode is one meter long’ is contingent (coul be different) though established a priori.[9]
   The problem is that Kripke gives no reason for this conclusion, except his assumptions on rigidity versus accidentality. Beside this, why cannot ‘one meter’ be an abbreviation of ‘the length of S after (or in) to, whoever this length is’, as it seems? Assuming this, our intuitive reasoning would be to think that if the length changes the meter itself isn’t different, since the standard meter is defined as whatever length S has when used as a pattern after (or in) to. Suppose that the standard metter were elastic, always changing; it would remain the same standard meter, even if very unpratical. If you consider this statement in this way, the statement is necessary, since it cannot be false (it is true in any possible world), and beyond this it is a priori, since we don’t need the experience to know its truth (it exemplifies the law of identity). It means more precisely:

Paris platinum rode is one meter long (as a standard to be met in any counterfactual situation).

If you decide to treat it differently, comparing different possible standard meters in different times or different counterfactual situations, then you are reading the statement ‘Paris platinum rode is one meter long’ as something like ‘the standard meter in w1 has the same length as the standard meter in w2’, which is a contingent a posteriori statement and not as a conventionally established necessary a priori, as it was made to be used. In this case it means more precisely:

Paris platinum rode is one meter long after in t0 (if compared with the standard meters that could be given in different times or in any counterfactual situation).

And this is false: the platinum rode could have one meter in some situations and in others not if you use as standard of comparison platinums rodes given in different situations.

4. Another attempt to exemplify the contingent a priori is the example of Gareth Evans’ with the name ‘Julius’, which is artificially conventioned as ‘the inventor of the zip.’ It is a priori because we don’t need the experience to know this.[10] But it is contingent since it is possible that the zip were not invented or that was invented by another person...
   Here again we can see Julius as a conventioned abbreviation for ‘the inventor of the zip’, what makes ‘Julius is (conventioned as) the inventor of the zip’ a necessary a priori sentence, since it is not only known as true independently of the experience, but is also necessary, since it is a linguistic convention independently of who invented the zip or even if the zip was even invented. I guess that the sentence seems to be contingent only because ‘Julius’ can be confused with a normal proper name rigidly referring to a real inventor of the zip.

5. A related funy example is the following utterance: ‘I am here now’. According to David Kaplan, this is a kind of contingent a priori truth. According to him it is a priori because since each term refers directly respectively to the agent, the place and the time of a given context of utterance, it cannot be false. But since we can imagine a possible world where I would not be here its utterance is only contingently true.[11]
   The answer is that this example is also delusive. For ‘I am here now’ can be false in the actual world too. I remember the case related by Dr. Oliver Sacks of a pacient who had a seriously deranged perception of the continuity of time. Because of this, her daily life was formed by time lapses, so she could think ‘I am here now’ as if she were still in the sleeping room, when in fact she had already moved to the kitchen. So, ‘I am here now’ is in this case false. We are dealing with a contingent statement, which being dependent of the context of the experience is also a posteriori: a contingent a posteriori statement.

 6. A not very dissimilar line of reasoning concerns my objections against Hilary Putnam’s view that the meaning of the word ‘water’ must be external to our heads. This is perhaps the most influential argument for semantic externalism. According to Putnam’s thought-experiment, in 1750 Oscar-1 in the earth and Oscar-2 in the twin-earth – both nearly identical planets with the same history – seeing that it rains, could have only the same idea of a watery liquid (transparent, inodorous, tasteless…) within their heads. However, without their knowledge, they were refering to very diferent composits, the first H2O and the second XYZ, since the water in the twin-earth has a very different chemical composition. For Putnam this proves that the meaning of water – which for him concerns essentially amounts of atoms with the same microstructure H2O – wasn’t in the heads of the Oscars, since in their heads they had the same thing, namely, the idea of a watery liquid. Consequently, the meaning isn’t in the head.[12]
   Our answer to this objection is to notice that the word ‘water’ has two nuclei o meaning.[13]  First there is an old popular nucleous of meaning of the word ‘water’ which can be summarized as ‘watery liquid’ (…the under normal temperatures transparent, inodourus liquid, that quenches the thirst, extinguish the fire, has high superficial tension, etc.) and was the only meaning in the market until the beginning of the XIX century. Then a new meaning was increasingly additioned, the scientific nucleous of meaning that can be summarized as ‘quantities of H2O’ (which results from 2H2 + O2 = 2H2O, can be subjected to electrolysis, forms intermolecular hydrogen bounds responsible for its superficial tension, etc.). Both nuclei of meaning are descriptive and can be pointed out today in good dictionaries.
   However, in consonance with the context of interest, one of these meanings comes often to the fore. The two Oscars in 1750 had only the meaning ‘watery liquid’ in their heads, as the extension of the word water were the same for them. But when Putnam considers what is going on, he is unconsciously projecting the diferent scientific meanings of the word water in the work of the two Oscars, treating the Oscars as indexical devices to the projection of these diferent meanings which are in our heads, since Oscar-1 is pointing to H2O, while Oscar-2 is pointing to XYZ. Consequently, the different meanings of the word ‘water’ are not in the world, as Putnam believes, but in Putnam’s head when he thinks his thought-experiment; and since Putnam and his readers have different meanings in their heads by projecting them to the Oscars unconsciously used as indexical devices, the meaning remains, as it should, an internal property of minds.
   Furthermore, in the neodescriptivist view that I defend, the meaning of ‘water’ varies with the context of interest in which the word is used. In a scientific context of interest (e.g., in a laboratory of chemistry) ‘Water is H2O’ means (a) ‘H2O = hidroxid of oxigen’: an analytic statement. In this context even if water weren’t a watery liquid, having the right chemical structure it would remain water.
   Now, in a popular context of interest (e.g., of fishermen wishing to use water for drinking and washing) ‘Water is H2O’ is an a posteriori synthetic statement that can be made false, since the privileged sense is here ‘Water is a watery liquid’, so that the substitutional sentence would be (b) ‘Watery liquid = liquid composed of H2O’, and it is not something necessary that a watery liquid is composed of H2O.
   Conclusion: Putnam’s and Kripke’s classification of the statement ‘Water is H2O’ as a necessary a posteriori statement is only a confusion between the necessity of the statement (a) and the aposteriori nature of the similar statement (b), resulting from lack of attention to the pragmatic of normal language.
   The point can be easily generalized. Consider the statement (i) ‘Hydrogen is constituted by atoms containing one proton and one electron’. One could say: though necessary, it was discovered a posteriori. But in fact it has at least two contextualized senses: First, if you think in the transparent inflammable gas discovered by Cavendish in 1766 and called by him ‘unflammable air’, which was later analysed as constituted by atoms with one electron and one proton, statement (i) is read as contingent a posteriori; this gas could have a different atomic structure and one could spell the statement as ‘Inflammable air is constituted by atoms containing one proton and one electron’. On the other hand, as we conventionally established the meaning of hydrogen as a gaz containing atoms with one electron and one proton (as we do definitionally in science today), (i) will be read as a necessary a priori statement, because it could be unpacked as ‘Hydrogen (Df) = the gaz constituted by atoms containing one proton and one electron’ assuming modern chemistry.

7. There are two others examples of Putnam intending to show that the meaning is not only in the external physical world, but also in the society.[14] To be brief I will consider hier only the first one. Putnam assumes that aluminium and molybdenium are only distinguishable by metalworkers and that the twin-earth is full of molybdenium. In addition, he imagines that the inhabitants of the twin-earth call molybdenum aluminum and vice versa. In this case, of course, the word ‘aluminum’ said by Oscar-1 will have an extension other than the word ‘aluminum’ said by Oscar-2, so that they mean different things with the word. But as they are not Steelworkers, they have the same psychological states. Hence, the real meaning of these words is external to what happens in their heads, depending on the society.
   The answer is that if we consider the words ‘aluminium’ and ‘molybdenium’ in the way they were used by Oscar-1 and Oscar-2, the Oscars are unable to really decide if what they have is aluminium or molybdenium, since they are not experts and what they have in their minds is indeed the same. For the stellworkers, on the other hand, the aluminium and molybdenium have very different constitutive properties, what means that they would have something different in their heads, though they use these words with exchanged senses. The Oscar’s may confuse both things, but only because they do not know really what these things are: they are using the words in a secondary, almost parasitic sense. Finally, we can consider the aluminium and the molybdenium observed by Oscar-1 and Oscar-2 and take both as referential devices, so that we would say that Oscar-1 is pointing what he calls molybdenium, but which is what we call and understand by aluminium and vice versa.[15]
   Putnam appeals to a division of labour of language in order to explain the different aspects of meaning that may be considered by different speakers. This is a useful idea. But this isn’t an idea that confirms an externalist conception of meaning. It is rather neutral, for the idea of a division of labour of the language was already suggested by internalist philosophers from John Locke to C. S. Peirce.[16] In effect, this idea is perfectly compatible with the difference in the fact that, even if being social, the meaning remains in the heads of the speakers, specialists or not, in different dimensions and degrees. In none of my explanations above the meaning was outside the heads (see Appendix of chapter 1).

8. Finally, I wish to reinforce my anti-externalist arguments considering Tyler Burge’s externalism of thought concerning the concept of arthritis, which is complementar to Putnam’s argument. What Burge intended was, apart from Putnam, to show that not only the meaning is outside the head, but the beliefs extension, i.e. the proper content of thought. I will first summarize the argument of Burge and then show that there is a much more plausible internalist explanation for what happens. Although Burge states his argument supposing a counterfactual situation, it is easier to suppose that a person with the name Oscar-1 feels pain in the thigh and see a doctor saying:

I think I have arthritis in the thigh.

   Since arthritis is seen as a painful inflammation of the joints, the doctor explains to him that his belief is false, that he cannot have arthritis in the thigh. Imagine now that Oscar-2 in the twin-earth is visiting a doctor for the same reason. But differently from here, in the twin-earth it is customary to use the word ‘arthritis’ in a much broader sense, to refer to any kind of inflammation. Suppose that in the linguistic community of the twin-earth Oscar-2 says to the doctor ‘I think I have arthritis in the thigh.’ In this place, as one would expect, the doctor will confirm the suspicion, agreeing that this is an unquestionably true belief.
   Based on this example, Burge’s reasoning would go as follows. Without doubt, the psychological States of the two Oscars when they said they believe to have arthritis in the thigh are exactly the same, as well as their behaviour. But the thoughts expressed in the two utterances, according to Burge, must be different, since the thought expressed by the first utterance is false, while the thought expressed by the second is true, and the same thought cannot be false and true. We may even mark the second meaning of the word ‘arthritis’ on the utterance of Oscar-2 with a new word, ‘tharthritis’. Burge’s conclusion is that the contents of thoughts cannot be merely psychological. These contents must belong also to the outside world, to the social communities involving the speakers.
   Against this conclusion it isn’t difficult to find an internalist-descriptivist explanation for what happens. For the internalism, the concept-word ‘arthritis’ is the expression of a characterizing or ascription rule constitutive of its meaning, which in the community of the twin-earth designates any kind of inflammation. According to this rule, ‘an inflammation that occurs in the thigh’ serves as a criterial condition and belongs to the sense of the word in the linguistic community of the twin-earth, though not in the linguistic community of the earth. Thus, although the content of thoughtexpressed in the sentence ‘I think I have arthritis in the thigh’ said by the to Oscars in their respective linguistic communities are exactly the same, there is a difference that was rightly recalled by John Searle in the following words: ‘Our use of language is presumed to conform to the other members of our community, otherwise we could not intend to communicate with them by using a common language.[17]
   That is, when Oscar-1 says to the first doctor ‘I believe I have arthritis in the thigh,’ he must be dispositionally assuming that his generalised rule of application of the predicate ‘arthritis’ belongs to the language that the other competent speakers of the language conventionally apply. The whole of what Oscar-1 has in mind (not only actually but also dispositionally) in his utterance to the first doctor in his linguistic community in the earth is:

(a)  I have arthritis in the thigh… [and I assume that the generalised criterial condition for the ascription of the predicate ‘arthritis’ is accepted as correct by the linguistic community speakers (of earth), to which belongs my interlocutor].

This is false because the second sentence of the conjunction is false. Let’s now see what is (actually and dispositionally) meant when Oscar-2 says that he has arthritis in the thigh:

(b) I have arthritis in the thigh… [and I assume that the generalised criterial condition for the ascription of the predicate ‘arthritis’ is accepted as correct by the community of speakers (of twin-earth), to which belongs my interlocutor.]

Now the statement (b) is true because it expresses a true conjunction. And the difference of meaning between (a) and (b) is clear because while (a) is indexically linked to the language community of earth (b) is indexically linked to the linguistic community of twin-earth. It may be true that if we confine ourselves to the content expressed in the thoughts of both Oscars in making the same utterance in the earth and in the twin-earth we see then as identical. But the whole of what they have in mind (that is, in their heads) with their utterances, including the dispositional content – the complete contents of what they have in mind – is more than that, because what is fully meant involves a hidden indexical assumption, whose truth can change with a truth-maker brought up by the linguistic conventions of the community involved.
   This assumption that the constitutive verification rules of thought should be in accordance with the conventions of the community of language in which it is expressed is infringed by Oscar-1 when he speaks with the doctor the of community of the earth, but it isn’t infringed when he speaks with the doctor of the community of the twin-earth. The assumption that the thought expressed must be in accordance with the rules of the language spoken by the community is not, however, something external to the speaker; it is a psychological element of dispositional order, supplementing the content of thought and that can be explained by any person whenever it is required.
   Nonetheless, Burge has called attention to one important thing: that the truth or falsehood of our utterances depends on the linguistic conventions accepted by the community involving the speaker. Only that against his claim, this dependency is not outside the mental in some way dispersed in the external social environment.
   Finally, the explanation given allows us make an internalist paraphrase of the well-known distinction between narrow content and wide content. For the externalist, the narrow content is one that is in the mind of the speaker, while the wide content is external: it is out there in the world or in the society. The internalist analysis of Burge’s example allows us to propose that the narrow content of thought is the semantic-cognitive verification rule that constitutes the thought (expressed by the phrase ‘I think I have arthritis in the thigh’), while the wide content of thought is what is assumed in the speaker’s mind as a provision whose expected existence will be arguably accepted.
   Now, after this too long excurse, it is time to turn back to Kripke’s paper.

The next of Kripke’s examples concerns the identity between kinds of things. Consider the statement Heat is molecular movement. Many think that this expresses an a posteriori truth, because it is the result of empirical scientific research. But for Kripke this is a necessary a posteriori identity, because the heat (in gases) cannot be anything other than molecular kinetic energy. It may be, he says, that the earth could at some time be inhabited by beings who feel cold where we feel heat and vice versa, so that for them heat would not be identical with molecular motion. But this would not be the case, since heat is understood as molecular motion as we feel it. For Kripke the terms heat and molecular motion are rigid designators, which make the identity between them unavoidable. For him the fact that molecular motion produces the sensation of heat is used to fix the reference, making the identity necessary; the illusion of contingency is due to the fact that we confuse this with the fact that our identification of molecular motion with the sensation of heat is contingent.

As in some already considered cases, we should distinguish between two cases: (i) identity between heat and molecular movement against the assumption of a theory, the contemporary termodynamics, and (ii) the same identification against the assumption of the changeable totality of our beliefs.
   In the first case we fix the meaning of the words in a way that makes the identity necessary: if we assume that modern thermodynamics is true, then ‘Heat (in gases) = overage cinetic energy’ is a necessary identity. But in this case the identity is necessary a priori, since under this assumption it is definitory. We can paraphrase the statement as:

(a)  [Assuming the truth of the modern temodynamics] the heat of gases as messed by termometers necessarily the same as its overage cinetic energy.

   Now consider the second reading, in which the statement ‘Heat of gases = the overage cynetic energy’ is opposed to our overall experience of the world, which does not assumed as necessarily remaining the same. Here the identity is contingent a posteriori, since our empirical knowledge taken as a whole is intrinsecally fallible. We can imagine that for nearly inconceivable reasons, findings show that almost all our science of chemistry should be revised, and we found that the best explanation for heat is, in effect, that it is a flammable fluid. In this case, it would be simply false to identify the heat (in gases) with molecular motion. Even if this revision has an extremely remote possibility, is not logically impossible. So from this perspective it is not logically necessary for heat to be molecular motion. The identity could be paraphrased as:

(b) With practical certainty (with probability near to 1) the heat of gases is the same as their overage cynetic energy.

   This statement is true, we believe, but nothing impedes that for some extremely remote reason it shows to be false.
   Kripke’s error consists in confusing the linguistic necessity of (a) the identification that we make between heat and molecular motion under the assumption of the truth of thermodynamic theory, which is a priori, with the a posteriority of the truth of (b), which depends on experience being therefore contingent, since at least in principle can evolve in a way that forces us to reject our former attributions of necessity.
   In a similar way as with the identity between names, considering heat and molecular motion as rigid designators that necessarily designate the same essence, we could build the following Kripkian argument calling H heat and M molecular motion:

     (x) ((Hx = Mx) → (Hx = Mx))
     (x) (Hx = Mx)
     (x) (Hx = Mx)

   However, the same kind of difficulty returns here. The first premise says only that if it is really the case that (x) (Hx = Mx), then it is necessarily the case that all heat is molecular motion, or, from an epistemic perspective, if it is absolutely certain that all heat is molecular motion, then it is necessary that all heat is molecular motion. However, the identity expressed in the second premise is always concluded by fallible epistemic subjects, even if they have very good reasons to believe it to be true, which again allows us to construct a paraphrase of the above argument that highlights the misconception:

    (x) If it is absolutely certain (with probability 1) that (Hx = Mx),
          then (Hx = Mx).
    (x) It is practically certain (with probability near to 1) that (Hx = Mx).
    (x) (Hx = Mx)

   To this we could add that even if H and M are rigid designators, this would not warrant identity, since we cannot be absolutely sure that they rigidly designate the same thing.
   There is some difficult in analysing cases like these, because we still don’t have a sufficiently developed descriptivist theory of concept-words. However, it seems that if we apply our neodescriptivist view of proper names to concepts, we can drop the localizing description-rule, since concept-words do not refer to something with a pre-established spatio-temporal location. The conceptual ascription rule is restricted to a kind of characterizing description-rule of the conceptual term.
   Here also the context of interest is decisive. Since the feeling of heat is given to us as something very different from molecular motion, ‘(x) (Hx = Mx)’ is usually seen as an a posteriori and contingent statement. On the other hand, if we, in the scientific context of a laboratory, define heat as the same thing as molecular motion (in gases), assuming the truth of modern thermodynamics, calling heat H’, for us (x) (H’x = Mx), which being an instantiation of the law of identity is a priori and necessary. Correct as it may be, it is another example of triviality.
   The Upshot of these remarks is that it seems that whenever we seem to have a necessary a posteriori truth, close consideration of the contextual changes in meaning shows that what we really have is always either a contingent a posteriori or a necessary a priori truth.

The last of Kripke’s examples should be the most important one. It is a refutation of the type-type identity theory of the mind-body relation, according to which ‘Pain is such and such a brain state’ would be a contingent, a posteriori scientific discovery, yet to be made. But, writes Kripke, ‘pain’ and ‘such and such a brain state’ are here rigid designators, because they refer to essential properties. However, if that’s the case, the identity theorist is in trouble, because the identity needs to be necessary, which clashes frontally with the fact that whenever you feel pain you do have a pain, while no one is denying that it is possible to conceive that we have pain without having the corresponding brain states. For Kripke this makes identity theory improbable.
I find this argument puzzling. First, one can as a matter of fact feel pain without being in pain – as can be done with hypnotized people. Kripke saw that there is here an assimetry between the ways we know each flank of the identity sign. In fact there is. But he didn’t have shown why this assimetry compromises the possibility of fixing a possible necessity of the identity under the supposition of his own theory of de re metaphysical identity. Hence, he hasn’t show anything that makes his conclusion convincing.
   Aside from this point, the objection here is the same as in the previous examples: from a purely ontological point of view it is always possible that pain is necessarily the same thing as some sort of brain state. The problem is that only God, the omniscient knower, would be able to know this in an absolutely sure way. For epistemologically fallible subjects like us, this identity can be only (a) postulated as a necessary a priori truth (such as an identity sentence resulting from the putative assumption of a future neuro-scientific theory of pain) or it is (b) a contingent and a posteriori truth, since from a more general perspective the identity is able to mirror the ontological reality only in a probable way.
   In my view most of these cases Kripke mixes the necessary element of something conventionally established as necessary a priori with the a posteriori element of a contingent a posteriori discovery, making us believe in a metaphysically de re grounded necessity a posteriori. In doing so, he assigns to an epistemologically alleged identity the same status of an ontologically unknowable identity. He thinks as if we could assert ontological (metaphysical) truths without regarding our epistemic capacities and their limits. He refuses to believe that we cannot ever separate completely the epistemic from the ontologic – a point that modern philosophers from Descartes to Kant were already aware, namely, that we lack access to any transepistemic truth.

[1] Saul Kripke: ‘Identity and Necessity’, published in Identity and Individuation, ed. M. K. Muniz (New York: New York University Press, 1971).
[2] Saul Kripke, Naming and Necessity (Oxford: Backwell, 1980).
[3] This view is defended by John Searle, Intentionality (Cambridge: Cambridge University Pr
ss, 1983), p.
[4] Ludwig Wittgenstein, Über Gewissheit (On Certainty) (Frankfurt: Suhrkamp 1984), Werkausgabe vol. 8.
[5] Ludwig Wittgenstein, Bemerkungen über die Grundlage der Mathematik (Remarks on the Foundations of Mathematics) (Suhrkamp: Frankfurt 1984) Werkausgabe vol. 6, part VII, p. 437.
[6] From C. S. Peirce to Karl Popper, philosophers of science have insisted that modern science has reafirmed that empirical knowledge is always fallible and open to possible refutation. See C. S. Peirce, The Essential Peirce: Selected Philosophical Writings 1 (Indiana: Indiana University Press, 1991), chap. 7. See also Karl Popper, Logik der Forschung (The Logic of Scientific Investigation) (Mohr Siebeck: Tübingen 2005 (1935)).
[7] The identification rules have the same form demanding a disjunction of a localizing and a characterizing description, but I am stating them in a simplified form.
[8] Kripke, Meaning and Necessity, p. 112 ss. Kripke uses as example Elisabeth II, the Queen of England, which due to the singular characterizing description gives more importance to his ovulo origin.
[9] Kripke, Meaning and Necessity, p. 56.
[10]  Gareth Evans, The Varieties of Experience (Oxford: Oxford University Press, 1982), p. 31.
[11] David Kaplan, ‘Demonstratives: An Essay on the Logic, Metaphysics, and Epistemology of Demonstratives and other Indexicals’, in Themes from Kaplan , eds. J. Almog, J, Perry, H. Wettstein (Oxford: Oxford University Press, 1989), p. 509.
[12] Putnam qualifies his ‘discovery’, admitting that a secondary part of the meaning – the stereotypes – is in the head, but this presently does not mind. See Hilary Putnam, ‘The Meaning of “Meaning”’, in his Mind, Meaning, and Reality – Philosophical Papers (Cambridge: Cambridge University Press, 1985), vol. 2.
[13] I will strongly summarize here. The full argument, which previously demands a careful neodescriptivist analysis of the meaning of the word ‘water’, is exposed in the chapter 3 of my book Lines of Thought: Rethinking Philosophical Assumptions (Newcastle upon Tyne: Cambridge Scholars Publishing, 2014).
[14]   To be fair, Putnam expresses himself more careful in a later writting by saying that the meaning is determined by the external world. But either we understand this in the sense that it is the external world that ultimately produces these meanings in our minds, what is an obvious truism that no internalist would wish to deny, or what he means with the word ‘determination’ remains a too subtle metaphor to be explained. See H. Putnam, Representation and Reality (Cambridge Mass.: MIT-Press, 1988), chap. 2.
[15] Others externalist arguments can be more easily answered. See, for example, John Searle, Mind: A Brief Introduction (Oxford: Oxford University Press, 2004)).
[16] See A. D. Smith, ‘Natural Kind Terms: A Neo-Lockean Theory’, European Journal of Philosophy 13 (2005), pp. 70-73.
[17] J.R. Searle: Mind: A Brief Introduction, Introduction (Oxford: Oxford University Press, 2004), pp 184-5.