Tuesday, 20 April 2021

Duncan Pritchard’s take on On Certainty

I’ve been chatting to a UCLan UG philosophy student (‘Olly’!) about hinge propositions in Wittgenstein’s On Certainty (OC). I’ve got a basic familiarity with OC and deploy some slogans when summarising it, but it occurs to me that these may be largely false. And hence, having time (while mad and ill), I think I ought to sit down in my study and, just this once, try to check my reading of it. 

The sort of thing I tend to say is that OC is radical because LW separates the game of giving and asking for reasons, of knowledge and doubt, from certainty. A framework of both animal and inherited certainty is the condition of possibility of knowledge claims and also of claims to doubt since doubts, too, take work and a context to make them reasonable. (On this, I like to remind myself that claiming that one didn’t know one’s suspiciously suddenly dead partner’s bank balance will not get waved through as it might in an epistemology class. One can be assumed to have picked up knowledge - rubbing off on one like an infectious disease - unless there is good reason why not.)
I take it that OC may (try to) do two independent things differentially well or badly. It may give a philosophico-anthopological description of knowledge claims and a background of certainty such that rival epistemological accounts of every day knowledge may be tested or supported. And it may provide a response to forms of scepticism. The latter, and perhaps the connection between the two, is suggested by the way it begins with Moore. Still, there are a number of responses to OC out there and I’ll start (in this post) with Duncan Pritchard’s in his Epistemic Angst (Pritchard 2016). (Next week I’ll look to Daniele Moyal Sharrock and also to Michael Williams.) Embarrassingly I’m not even going to try to follow his fascinating – if you go for that sort of thing – discussion of variants on the closure argument to generalise scepticism. I’m just going to try to think about the conclusion, baldly. (I’m not thinking well at the moment.)
But to get to that I just want to outline how I think, at least, scepticism is supposed to get off the ground. I’m doing this for me, I hasten to add. Epistemologists would be distressed by my Noddy guide. 

I think that there are three steps.
Step one. Knowledge is incompatible with luck (roughly!)
There is more to knowledge than true belief. Consider this case:
In a pub quiz, I am asked for the first name of a familiar looking person in a picture. I say “John as in Jedward” and get it right. My partner says: “Wow I’m impressed! How did you know it wasn’t his twin Edward” and I reply: “I didn’t know he had a twin”. Did I know who it was?
Intuitively, I did not know it was John even though my belief was true because it was based in a knowledge-undermining way on luck. Had I been shown a picture of Edward, I would also have said “John” and got the answer wrong. So the truth of my belief depended on my good luck to be shown the right picture. I could not tell the difference between John and Edward, and hence I did not actually know the picture was of John. The same applies to rolling a fair dice and saying that it will not come up six. This may turn out to be true. But it still depends on luck. One cannot know that a fair dice will not come up six. Nor can one know that a 100 sided dice will not come up 100. Despite the increasingly good odds that make this a good bet, it would still be a matter of luck. So knowledge is true believe without the intervention of luck. It is this that is the basis of scepticism.
Step two. The ringer.
The sceptic does not aim to undermine knowledge by showing that what we think we know is actually false. Rather, they target the no-luck condition of knowledge. For Cartesian versions of scepticism, they do this by postulating a ‘ringer’ which we cannot tell apart from the veridical case. Eg that we might be a brain in a vat (BIV in what follows). (A ringer is a horse substituted for another of similar appearance in order to defraud the bookies. This word originated in the US horse-racing fraternity at the end of the 19th century.) 
With a well chosen ringer, no empirical evidence can rule it in or out. So if the BIV ringer is possible, even if our belief in the everyday external world turns out to be true (whether or not we could know that), it fails to be knowledge because it is true merely by good luck. Like the case of the dice coming up 6, the sceptic does not even have to claim that the ringer is likely. It just has to be possible and also impossible for us to rule it out. So if I can’t tell the difference between being an embodied human in the empirical world and being a BIV then I cannot know the former. Even if the former is true, my belief in it isn’t knowledge. And this is because of something like a no-luck condition which is undermined.
So the sceptic has got as far as arguing that we cannot know that we are not a brain in a vat. 
Step three: closure.
Here’s where I will demonstrate my crass ignorance of the literature on closure. But starting naively, closure is based on a syllogism. If P, and If P then Q, Then  Q. There’s a modus ponens and a modus tollens reading of the inference. Staring with two empirical claims: If I am in Kendal, then I am on Earth. If I am not on Earth then I am not in Kendal. 
Relevant here is the way that closure has been used in epistemology applied not just to P and Q but knowledge of P and Q or beliefs concerning them or rational entitlement to such beliefs. (One says that knowledge is closed under known entailment.) Suppose I know that P. It might seem that if I know P and if P implies Q then I should be able to know Q. This will fail, of course, if there is some impediment to me knowing the implication. And hence we need to refine the statement of a closure principle to include saying I also need to know the implication. And sadly, that’s just the start of the refinements. (See Pritchard’s book for one set of developments.)
Things get more relevant to scepticism when closure isn’t applied within a set of everyday empirical claims but from one or more of those to sceptical ringers and vice versa. If I am in Kendal, I am not a BIV. If I know I am in Kendal then I (am able to) know I am not a BIV. But if I cannot know that I am not a BIV, then I cannot know I am in Kendal. Applied to the sceptical ringer, then if I cannot know that the sceptical ringer is false then I cannot know any of the empirical claims that would imply that I am not a BIV. Etc. 
Closure spreads the infection of scepticism from the ringer to nearly everything else.
Pritchard on closure based arguments and On Certainty.
There’s much going on in Pritchard’s book but one strand concerns the attempt to find a way to address what seem to be three incompatible claims.
The Inconsistent Radical Skeptical Triad 
(I) One is unable to know the denials of radical skeptical hypotheses.
(II) The closure principle. 
(III) One has widespread everyday knowledge. (ibid: **)
And one main way he attempts to do this is to find a reading of the closure principle which holds true but which does not govern the denials of radical sceptical hypotheses such as to imply a lack of everyday knowledge. I am going to ignore the subtlety of that in order baldly to present the destination. In this, I am following the pornographer publisher of Anais Nin who told her to drop all the plot details and just focus on the hard grinding action.
But it is worth noting in passing that in late C20 American epistemology, one approach was to deny closure to insulate sceptical philosophical language games infecting everyday knowledge claims. Another was to keep closure but to argue that changes in context ruled out its assumed implications for the everyday.
So let’s jump ahead. In On Certainty, it seems that Wittgenstein deploys the metaphor of hinges as necessary fixed points about which empirical inquiry turns.
The questions that we raise and our doubts depend upon the fact that some propositions are exempt from doubt, are as it were like hinges on which those turn. That is to say, it belongs to the logic of our scientific investigations that certain things are in deed not doubted. But it isn’t that the situation is like this: We just can’t investigate everything, and for that reason we are forced to rest content with assumption. If I want the door to turn, the hinges must stay put. (OC §§341– 43)
Again playing fast and loose with themes about which there are opposing views from different interpretations of OC, one approach to these hinges is to distinguish them from knowledge claims. A refrain in OC is LW saying that particular claims to know, just as much as claims to doubt, fail in some way. Assuming that the failures of speech acts infect the knowledge status claimed (an assumption Michael Williams challenges) and it may be that what the sceptic targets and what epistemologists defend are not suitable for knowledge status. And that may suggest that they can fall out of the range of the closure argument: from a failure to know the falsity of a sceptical ringer to the failure of empirical knowledge in general. 
A comment along the way. Although this is Pritchard’s way with hinges, it seems to miss a more basic point. The Cartesian sceptic’s argument gets off the ground with a ringer. Closure comes in to show why this is significant for nearly all our other beliefs. But OC seems more directly to challenge the cogency of the sceptic’s argument about ringers. If the sceptic is wrong about these, then there’s not the same need to worry about closure. This may need a bit of assessment depending on exactly how hinges resist sceptical doubt but it is odd that Pritchard seems just to ignore it.
One way of thinking about why hinges are not proper candidates for knowledge or doubt is that they are not genuine propositions and hence not the right objects of attitudes (see Moyal Sharrock but also Malcolm and McGinn). One cannot be committed to something that fails to set out a way things might be. But I’m not going to write about the non-propositional view of hinges because Pritchard rejects it. His main objection to the non-propositional view seems to be that, even if it is textually the best fit with OC and even if it has some plausibility - via the idea that hinges are action-related, practical behavioural rather than thought-like - it is still easy to generate a proposition from its account of hinges. So it is hard to maintain that hinges are fully not propositions when there are propositional readings of them. Further, in the context of his worries about closure, once there is a proposition for each hinge, it looks as though the closure argument can start. 
(Note though that while this is the right thing for him to say dialectically at this point in his book, in fact, 20 pages later, he will provide a way to having a proposition in play while blocking a closure based argument to scepticism. This is his own position.)
Pritchard suggests a propositional but non-belief reading of hinges and an interpretation of the closure principle that simply does not apply to them. Hence, all three elements of his sceptical triad can hold true: they are not actually incompatible, after all.
The development of his own account puts some weight than on the idea, not found in OC of an ‘über hinge’. Having described a variety of types of hinge varying in the range of application from the personal to the universal he comments:
The foregoing suggests a highly context-sensitive account of hinge commitments, and one might be tempted on this basis to regard one’s hinge commitments as being entirely context-bound. But this would be an unduly quick way of reading Wittgenstein’s remarks on hinge propositions. For closer inspection of this apparently heterogeneous class of hinge commitments reveals that they all in effect codify, for that particular person, the entirely general hinge commitment that one is not radically and fundamentally mistaken in one’s beliefs. Call this commitment the über hinge commitment, and call the proposition endorsed by the über hinge commitment the über hinge proposition. (ibid: **)
Pritchard points out - around p100 - that (the modus ponens version of) closure cannot imply the über hinge. Knowing I’m in Kendal does not imply that I’m generally right across the board. So - (via modus tollens)- not knowing the über hinge doesn’t threaten my knowing I’m in Kendal (and every other empirical claim). While I may not know I’m a stable genius, still I might know that fact. Still, that’s not what the sceptic targeted. The ringer is a specific, but knowledge-undermining claim, such as that I’m a BIV. And here a modus ponens closure argument does seem to work. If I know I’m in Kendal then I know I’m not a BIV. (So if I don’t know the latter, I don’t know the former.)
How does Pritchard block this? Around p101-103, if I follow, he just seems to set about constructing what a non-belief propositional attitude towards the negation of BIV would like like and pray that it solves his problem.
We do not normally encounter radical skeptical hypotheses in ordinary life, and yet we can be easily made aware of their incompatibility with our everyday beliefs. These hypotheses are thus ripe for the kind ofcompetent deduction at issue in closureRK- style inferences. The result of these inferences is plausibly a kind of propositional attitude toward the entailed proposition, whereby we recognize that we are committed to regarding it as false. But if this propositional attitude is not one of belief, as maintained above, then what kind of propositional attitude is it? (Ibid: **)
He suggests that it is a commitment and hence is not mere agnosticism towards the possibility of BIV. He also argues that the fact that it may seem like a belief to a subject who holds it is no guide to it actually being (cf mistaking a piece of wishful thinking for a rationally held belief). Perhaps this is a legitimate activity: constructing a propositional attitude to suit a philosophical purpose. It is a pity, however, that so little of its functional role is described.
Now whatever exactly this commitment to not-BIV is, we might still worry that it will still support closure. Pritchard says not because:
For the propositional attitude that results from such deductions in these cases, while superficially similar to belief, cannot be a genuine (knowledge- apt) believing, but is instead a mere codification of the prior über hinge commitment, a commitment that is not acquired via any rational process, much less the result of a specific rational process like a particular competent deduction. Rather than this being a counterexample to the closureRK principle, such cases of deductions involving one’s hinge commitments are instead better characterized as instances where the closureRK principle is simply inapplicable. (Ibid: **)
So the über hinge reappears. My commitment to not-BIV is itself a codification of part of that. It’s like a deduction, perhaps, or a local application of that wider commitment. Given the über hinge then not-BIV. 
But it would now be question begging if he relied on the earlier argument about why the über hinge doesn’t link to closure (because he has just invented this über hinge notion and has provided us with no independent argument to accept it). So let’s see why we cannot infer knowledge of not-BIV from knowledge that we are in Kendal? Well, it’s already in the above quote. It turns on this claim that a hinge is:
a commitment that is not acquired via any rational process, much less the result of a specific rational processlike a particular competent deduction. (ibid: **)
What should we make of this?
First, we could disagree with him. Again, if I remember accurately (and I may not), Michael Williams suggests that I can know that I’m not-BIV via what looks like a rational process. Since nothing speaks for being a BIV because being a BIV is not a possibility – it is akin to a fairy tale - then excluding it seems (to me) to be rational. McDowell suggests that I can know that I am n to a BIV because I can see the roofs of Kendal around me. This is fallible, but in the good disjunct, I do have knowledge that I’m in Kendal and hence not a BIV. (I have knowledge because I can see the very roofs. If I can see them - really them! - then there is no luck involved in my knowing them to be there. The roofs themselves inform/justify me.)
But suppose we grant Pritchard that not being a BIV is presupposed by inquiry rather than earned by it (and this seems a better fit with much of OC), why isn’t there still a problem when I come to reflect on my knowledge when urged on by the sceptic? I realise that being in Kendal implies not being a BIV. So if I cannot know not-BIV, surely this should worry me? While it is true in general that we did not first satisfy ourselves of not-BIV before the sceptic arrived, if the sceptic points out that not only did we not bother to try to know this but actually we couldn’t know it, why isn’t that a problem? I come easily to realise that I were a BIV then I could not be in Kendal which is precisely what I now wish to know. 
Pritchard correctly points out that I do not believe not-BIV via an inference from believing I am in Kendal, or suchlike. I just don’t believe BIV. I have an a-rational commitment to not-BIV. Given that I did not derive not-BIV from empirical beliefs, I would still hold not-BIV if I had a whole set of other (false) empirical beliefs. Holding not-BIV is not dependent on any inference. Let’s grant all that before the sceptic arrives.
But now the sceptic raises a question of whether my belief in not-BIV is well supported. Do I have reason to hold it true? Do I have reason to think I can know it? Given that BIV implies not-Kendal, why does this not worry me?
Pritchard may reply that I should not worry because I don’t believe not-BIV, I just hold it. This seems to me akin to saying: “Don’t worry, while you have no rational grounds to hold it, you do wish it were true; it does flatter your vanity to hold it! You voted BREXIT similarly! And that all went well didn’t it?!” In this context, the idea that I was lax before I met the sceptic is no help to me. I want to take the content, the thought - not-BIV - and hold it up to scrutiny precisely as Descartes suggested, once in a life time, we should all. I may not have believed it before, I may not have considered it at all, but now I wish to believe it for rational reasons, to know it with no debt to luck.
Thus to be told that I have an a-rational commitment to not-BIV (of a form whose precise nature has not yet been sketched) seems to me to be no response to the sceptic except to concede everything important to her.

Tuesday, 13 April 2021

Triangulation: the solitaire strikes back

I’ve been reading Donald Davidson’s Triangulation Argument A Philosophical Inquiry by Robert H. Myers and Claudine Verheggen (2016). To declare an interest and a debt, Claudine edited a book which included an essay of mine (on McDowell, Wittgenstein and Davidson). I’ve never really bothered to think carefully about the triangulation argument but time off work because of a nervous breakdown has offered me opportunity if not mental capacity to have a look both at Davidson and this very helpful book.

I realise that I’ve always taken the triangulation argument to suggest a kind of Humean view of meaning, on the model of Hume on causation or moral judgement. Genuine objectivity about meaning is put under threat, at least, of reconstruction as a form of projection. On a McDowellian-Wittgensteinian view of Davidson, meanings are essentially conceptualizable only from the perspective of radical interpretation, without this implying that radical interpretation constructs meanings. Starting with a McDowellian-Wittgensteinian view, Davidson’s ‘Philosophy of Language of the Field Linguist’ based on Radical Interpretation is entirely consistent with taking meanings to be genuine features of the fabric of the world. It is another instance of a McDowellian trope that realism of that sort is consistent with features of the world requiring particular, non-universal kinds of minds for their conceptualisation and detection.

But I have taken the later development of the triangulation argument to undermine this: to be more akin to Wright’s Wittgenstein than McDowell’s. However, looking again, it may be that my assumption turned not on the essays that set out the triangulation argument but, rather, Davidson’s pithy summary of it in the introduction to Subjective, Intersubjective, Objective [Davidson 2001].

Rather, the objectivity which thought and language demand depends on the mutual and simultaneous responses of two or more creatures to common distal stimuli and to one another’s responses. This three-way relation among two speakers and a common world I call ‘triangulation’. In the end, the idea is as simple as that of ostensive learning, but with an insistence that triangulation is not a matter of one person grasping a meaning already there, but a performance that (when fully fleshed out) bestows a content on language. [Davidson 2001a: xv italics added]

I should, perhaps, have spotted the tension in my reading of this passage in that it starts with a claim that objectivity – a conception of objectivity, I assume – is necessary for thought and language and ends with the claims about performance onto which I latched (though see below).

Certainly, there is no suggestion of this Wrightian anti-realism about meaning in Verheggen’s account. But before looking at that, I will set out the key passages from Davidson’s initial 1992 paper on triangulation: ‘The second person’ [ibid: 107-22]. I will work through the paper in order starting part way through in the run up to the triangulation argument.

To advertise my tentative conclusion in advance, I do not see how triangulation enables a condition on the objectivity of concept possession to be met in a way that also rules out a solitary thinker, or ‘solitaire’. Insofar as triangulation provides the material to meet the condition, the resources of the solitary thinker can be augmented while stopping short of adding second thinker or speaker and also meet the condition as I understand it. Further, if Davidson were right and being a solitary thinker were impossible, it is far from clear how adding a second and interacting solitaire to the first solitaire transforms the situation. Triangulation thus seems unnecessary to meet the condition and sheds no further light on how the condition can be met in abstract terms that does not also apply to the solitaire. The only difference I can see is a notion of joint intention that plays no role in Davidson’s thinking but might make the difference or the question begging assumption that triangulators can be assumed to be thinkers - perhaps ‘dignified’ to echo Blackburn’s criticism of Kripke - as thinkers while solitaires cannot.

One theme concerns the charge of question begging. I take it that the onus of proof lies with Davidson (and Verheggen) to establish the contentious claim that solitaires cannot be thinkers. It thus does not beg the question against him to assume pro tem that they are in order to inquire whether and how they can meet his specified necessary condition on objectivity. (Failure to meet the condition would require withdrawing the temporary assumption that they were thinkers.) Indeed that is precisely what he does for triangulators! He grants them the status as thinkers and then examines how they meet his condition. It can hardly be unfair to use the same strategy for those he attempts to disenfranchise.

Davidson’s initial account of triangulation

‘The second person’ starts with a discussion of the role of the concept of language for theorists. It goes on to consider the assumption in Wittgensteinian philosophy that communication requires that speakers go on in the same way. Davidson rejects this (for reasons that do not matter here). Instead, he claims that:

[S]peaking a language, we will now claim, does not depend on two or more speakers speaking in the same way; it merely requires that each speaker intentionally make himself interpretable to the other (the speaker must ‘go on’ more or less as the other expects, or at least is equipped to interpret). [ibid: 115]

This raises the following problem, however.

But haven’t we, by eliminating the condition that the speaker must go on as the interpreter (or others) would, at the same time inadvertently destroyed all chance of characterizing linguistic error? If there is no social practice with which to compare the speaker’s performance, won’t whatever the speaker says be, as Wittgenstein remarks, in accord with some rule (i.e. in accord with some language)? If the speech behavior of others doesn’t provide the norm for the speaker, what can? [ibid: 116]

This passage suggests a theme that lurks in the background of the paper as a whole and plays a much more explicit role in Verheggen’s account. It is the importance of a conception of objectivity based on a difference between a judgement’s being right and merely seeming right. Without this the necessary connection between a word having meaning (or thought having a content) and there being a difference between being right in its application (or a thought’s holding true) or being wrong cannot be made. Hence the triangulation argument to come is supposed – possibly among other things (see Verheggen) – to meet this challenge.

In defence of my previous assumption of a form of Humean projectivism (see my ‘see below’ above): Wittgenstein-inspired philosophers such as Wright and Kripke share an assumption in the putative importance of a distinction being right versus seeming right but provide a mere ersatz version of objectivity. So the mere fact that Davidson recognises something similar need not preclude the possibility that the triangulation argument merely provides an ersatz version of objectivity.

Davidson answers his question thus:

The answer is that the intention of the speaker to be interpreted in a certain way provides the ‘norm’; the speaker falls short of his intention if he fails to speak in such a way as to be understood as he intended. [ibid: 116]

This is stage-setting for the triangulation argument. It begins with consideration of the simple cases of dogs and children being trained and taught to recognise stimuli for reward.

The dog hears a bell and is fed; presently it salivates when it hears the bell. The child babbles, and when it produces a sound like ‘table’ in the evident presence of a table, it is rewarded; the process is repeated and presently the child says ‘table’ in the presence of tables. The phenomenon of generalization, of perceived similarity, plays an essential role in the process. [ibid: 117]

But now Davidson introduces a worry that has resonances of Quinean concerns about the inscrutability of reference.

This seems straightforward, but as psychologists have noticed, there is a problem about the stimulus. In the case of the dog, why say the stimulus is the ringing of the bell? Why couldn’t it be the vibration of the air close to the ears of the dog—or even the stimulation of its nerve endings? [ibid: 118]

One argument for retreating inwards is that the connections between such stimuli and the reactions of dog and child become more reliable.

Why not say the same about the child: that its responses are not to tables but to patterns of stimulation at its surfaces, since those patterns of stimulation always produce the response, while tables produce it only under favorable conditions? [ibid: 118]

It seems that when all that is in the picture is a dog responding to a causal chain that starts with the Big Bang and passes via the ringing of the bell to neurological events (and a similar causal chain for the child) there is no principled answer to what the stimulus is. This may seem to be merely a particularly philosophical worry. Outside a philosophical setting, there is rarely an insuperable practical problem even if there may be a problem with merely an initial snapshot of evidence. Allowing a pattern of reaction to stimuli to unfold provides a practical answer to any empirical interpretative ambiguity. This is the clue that Davidson builds into his broader picture of the scene.

What explains the fact that it seems so natural to say the dog is responding to the bell, the child to tables? It seems natural to us because it is natural—to us. Just as the dog and the child respond in similar ways to certain stimuli, so do we. It is we who find it natural to group together the various salivations of the dog; and the events in the world that we effortlessly notice and group together that are causally linked to the dog’s behavior are ringings of the bell. We find the child’s mouthings of ‘table’ similar, and the objects in the world we naturally class together that accompany those mouthings is a class of tables. [ibid: 118]

While a non-philosopher might have little patience with the worry Davidson articulates for the simple two component picture of ambiguous stimulus and canine or child reaction, this is because they find some ways of ‘reading’ the scene natural. Davidson employs this second (reader) reaction to suggest a broader picture. Now we have not only the child’s reaction to the table but also a second person’s. Their perception of similarity – naturally deployed by the impatient non-philosopher – enters the theoretical account of meaning and reference. But, as Davidson points out, this also depends on a third, implicit perception of similarity. The second person has not only to see relevant similarity in the stimuli that provoke a verbal reaction for the child in order to determine the reaction’s meaning, they also need to judge relevant similarities between those reactions. (A further addition is that, unlike a reader’s response, those involved in triangulation must interact.)

Involved in our picture there are now not two but three similarity patterns. The child finds tables similar; we find tables similar; and we find the child’s responses in the presence of tables similar. It now makes sense for us to call the responses of the child responses to tables. Given these three patterns of response we can assign a location to the stimuli that elicit the child’s responses. The relevant stimuli are the objects or events we naturally find similar (tables) which are correlated with responses of the child we find similar. It is a form of triangulation: one line goes from the child in the direction of the table, one line goes from us in the direction of the table, and the third line goes between us and the child. Where the lines from child to table and us to table converge, ‘the’ stimulus is located. Given our view of child and world, we can pick out ‘the’ cause of the child’s responses. It is the common cause of our response and the child’s response. [ibid: 119]

This is the heart of the triangulation argument. A brief pause. Davidson says:

Where the lines from child to table and us to table converge, ‘the’ stimulus is located. Given our view of child and world, we can pick out ‘the’ cause of the child’s responses. It is the common cause of our response and the child’s response. [ibid: 119]

The fact that ‘the’ is flanked by inverted commas seems significant. It suggests that there is something bogus about singling out any specific or definite stimulus from the extensive causal chain. And indeed, it is easy to generate alternatives. Imagine that a canine neurologist is attempting to discover the proximal cause of a specific bark reaction. They may well find it natural to say that a specific neurological precursor is the stimulus of the specific bark. So the specificity that enables Davidson to call the bell (or the table) ‘the’ stimulus turns on already viewing the interaction through the lens of ethnographic or radical interpretation. In other words, it prepares the way to think of the interaction of dog (or child) and world on the model of a conceptually articulated linguistic agent’s judgements. It is this that offers a route from a merely causal view of stimuli to intensional conceptualisations of the world. In other words, there is something illicit in starting where Davidson does, in causal interactions, and ending where he aims to finish, in intensional conceptualisations, with primitive triangulation as having made substantial progress. Primitive triangulation is not a half way point but no progress towards the intensional at all. Davidson himself points out that it sets out a necessary rather than a sufficient condition on acquiring concepts, such as the concept of table.

Enough features are in place to give a meaning to the idea that the stimulus has an objective location in a common space; but nothing in this picture shows that either we, the observers, or our subjects, the dog and the child, have this idea. [ibid: 119]

It is not completely clear to me what Davidson means by ‘have this idea’. The ‘idea’ is that ‘the stimulus has an objective location in a common space’ and it seems that if the triangulation argument works then it has shown that the child is using the word ‘table’ to refer to tables, rather than the Big Bang or neurological events. So how can they not have the ‘idea’ that they are using their word for that? That is not to say that they possess a meta-level theorists vocabulary that enables them to refer to words as ‘words’. But isn’t the idea of the table implicit in their use of ‘table’ as picked out by triangulation?

One possibility here – and this is discussed by Verheggen – is that such usage might exemplify mere non-conceptual primitive normativity as articulated by Hanna Ginsborg. Another is to invoke Evans’ Generality Constraint to argue that the child’s word usage may not amount to concept possession because it is not at the service of enough projects. According to the Generality Constraint, concept possession is essentially general and so someone who grasps a concept must be able to entertain a range of related thoughts employing the concept. As Verheggen points out, Davidson himself advances a very Evansian claim: ‘being able to discriminate cats is not the same thing as having the concept of a cat. You have the concept of a cat only if you can make sense of the idea of misapplying the concept, of believing or judging that something is a cat which is not a cat’ [Davidson 1999a, 124].

That the ‘idea’ concerns the concept of table accords with what Davidson goes on to say:

Nevertheless, we have come a good distance. For if I am right, the kind of triangulation I have described, while not sufficient to establish that a creature has a concept of a particular object or kind of object, is necessary if there is to be any answer at all to the question what its concepts are concepts of. [ibid: 119]

In other words, triangulation alone does not yield the idea that the attachment of the word ‘table’ to tables – rather than the Big Bang or neural episodes – amounts to possessing the concept of table. Still, articulating this necessary condition is enough to do some philosophical work. For example, it rules out solitary – which Davidson redescribes as ‘solipsistic’ – language users. The same passage continues:

If we consider a single creature by itself, its responses, no matter how complex, cannot show that it is reacting to, or thinking about, events a certain distance away rather than, say, on its skin. The solipsist’s world can be any size; which is to say, from the solipsist’s point of view it has no size, it is not a world. The problem is not, I should stress, one of verifying what objects or events a creature is responding to; the point is that without a second creature responding to the first, there can be no answer to the question. [ibid: 119]

I take it that by ‘verifying’ Davidson means some sort of conclusive justification. It is not that triangulation conclusively verifies the referents of terms. (I will later suggest that this reflects his Quniean heritage.) But it provides the resources in general to draw a distinction between being right and merely seeming to be right in determining where along the causal chain, the true referent of a word lies. By contrast, the solipsist lacks any way of drawing this distinction. But is this right? Has triangulation made a difference? Is solitary thought impossible?

This is a point to which I will return in Verheggen’s account. But it is worth raising a question and seeing how some resources in Davidson might address it. The question is suggested by Davidson’s assimilation of solitary and solipsist: how is either participant in triangulation better placed than the solipsist? The assimilation is suggestive because solipsists do not have to be solitary – at least as far as others are concerned – but rather take themselves to be solitary. They are their world. Hence it might be that, in the pattern of experience that a solipsist enjoys, there are what we might describe as a child or a field linguist and some tables, though the solipsist takes these merely to be their own dependent mental states. So how does triangulation help? Davidson says:

Unless the creatures concerned can be said to react to the interaction, there is no way they can take cognitive advantage of the three-way relation which gives content to our idea that they are reacting to one thing rather than another. Here is part, I think, of what is required. The interaction must be made available to the interacting creatures. Thus the child, learning the word ‘table’, has already in effect noted that the teacher’s responses are similar (rewarding) when its own responses (mouthing ‘table’) are similar. The teacher on his part is training the child to make similar responses to what he (the teacher) perceives as similar stimuli. For this to work, it is clear that the innate similarity responses of child and teacher—what they naturally group together—must be much alike; otherwise the child will respond to what the teacher takes to be similar stimuli in ways the teacher does not find similar. A condition for being a speaker is that there must be others enough like oneself. [ibid: 120]

One element of this passage is the claim flagged earlier in the paper that a condition for being a speaker is not mere interpretability but actual interpretation. (This, I think, marks a difficulty for a McDowellian-Wittgensteinian reading of triangulation and perhaps suggests the element of projectivism I previously assumed.) But the material to begin to respond to my question is that the child – or the teacher/field linguist – must take themselves to be in a relation to the other and to interact with them. That is, they must take themselves not to be solipsists. But can merely taking oneself not to be a solipsist be enough to draw a distinction between being right and merely seeming right on the assumption, pro tem, that the willing solipsist cannot draw this distinction? Again, this suggests an element of projectivism: one is a thinker if one takes oneself, and is taken by another, to be a thinker.

The distinction between being and merely seeming right will be a major focus of the second half of this paper. But what of the specific idea that triangulation is necessary to fix the reference of words or concepts, thus selecting ringing bells rather than the Big Bang or neural events? As I described earlier, Davidson does not think that primitive triangulation can help settle this matter. He moves from primitive to linguistic triangulation in order to make use of the fine grained intensions of both speakers. That is, he helps himself to intensionality rather than attempting to reduce concepts to extensional causal transactions even augmented by primitive triangulation. So, although he dismisses the resources of the solitary thinker to determine the  reference of their concepts, his own appeal to triangulation seems simply to trade on what both active parties in linguistic triangulation find natural. It is thus tempting to ask: what difference does having two of them make? Why is the salience and naturalness of a solitary thinker not enough? I suggest that the worry about reference is, again, a specific instance of the distinction between being and merely seeming right. Davidson thinks - wrongly, I think - that the solitary thinker cannot entertain an objective content that singles out a specific aspect of the world.

To end this section, consider this passage.

The only way of knowing that the second apex of the triangle— the second creature or person—is reacting to the same object as oneself is to know that the other person has the same object in mind. But then the second person must also know that the first person constitutes an apex of the same triangle another apex of which the second person occupies. For two people to know of each other that they are so related, that their thoughts are so related, requires that they be in communication. Each of them must speak to the other and be understood by the other. They don’t, as I said, have to mean the same thing by the same words, but they must each be an interpreter of the other. [ibid: 121]

One additional possibility that this suggests to me is the idea of joint intentions: intentions essentially constituted by two thinkers. If communication required joint intentions then solipsistic or solitary concept wielders would be swiftly ruled out. But more would need to be said about the nature of such essentially joint contents than Davidson does here. 

Having set out Davidson’s argument, I will turn to Verheggen’s sympathetic account and defence of the triangulation argument.

Verheggen’s triangulation argument

Again, I will proceed sequentially through the argument that is offered in my target paper: in this second half, chapter 1 of Donald Davidson’s Triangulation Argument A Philosophical Inquiry by Robert H. Myers and Claudine Verheggen, authored by Verheggen.

Verheggen starts by stressing the claim that the argument is a way to refine the fundamentally causal base of Davidson’s account of linguistic meaning and mental content, specifically, his causal externalist account of perception.

The triangulation argument is premised on Davidson’s perceptual externalism, the view “that the contents of our thoughts and sayings are partly determined by the history of causal interactions with the environment” (Davidson 1991a, 200).17 Thus, take the thought, ‘there’s a cow’. “What determines the content of such basic thoughts (and what we mean by the words we use to express them) is what typically caused similar thoughts” (Davidson 1991a, 201). The question is, though, what are the typical (or “normal” or “usual” (Davidson 2001b, 4)) causes of our basic thoughts and sayings? Davidson claims that if we were to observe a person who had never interacted with another and the world they share—call this person a solitaire—we could not answer this question. [ibid: 16]

This passage immediately suggests the way that Verheggen’s reading of the argument stresses – to a greater extent than seemed natural to me above – a contrast between triangulation and the ‘solitaire’. The contrast with the solitaire is explicit throughout Verhaggen’s account rather than, for example stressing a contrast between triangulation and a purely causal theory of reference. She also, however, introduces a helpful notion to characterise a purely causal theory. This is the aspect of an item to which a word or element of thought refers. This broadens Davidson’s emphasis on the extended causal chain into which putative stimuli belong. It links to her agreement with McDowell that a Davidsonian account should be a theory of sense rather than reference [ibid: 14].

The problem always remains of specifying which aspect of the item designated—which aspect of the cause—is the relevant one in the determination of meaning. Is it, say, the surface of the table, its color, its shape, the table itself, the table and its surroundings…? . [ibid: 18]

But the problem is that, while it may seem that triangulation helps address this ambiguity, it does not. It is no better off than a description of the solitaire’s resources.

Davidson briefly addresses this (first) problem immediately after introducing it by saying that the relevant part of the total cause is “the part or aspect of the total cause that typically causes relevantly similar responses. What makes the responses relevantly similar in turn is the fact that others find those responses similar; once more it is the social sharing that makes the objectivity of content available” (Davidson 1999a, 130). But sheer social sharing does not tell us in what respect shared responses are similar. Moreover, we are not told why a solitaire could not also find her responses similar, thereby putting herself in a position to fix their relevant causes. [ibid: 18 italics added]

She continues.

[R]eflecting on primitive triangulation affords us a diagnosis of the extent of the problem facing the externalist view, according to which the meanings of one’s thoughts and utterances are in part determined by what typically cause them. What the discussion of primitive triangulation brings to the fore is that the causes of one’s responses to one’s environment are ambiguous not just for the solitaire but for the triangulator as well. No matter how similar shared responses may seem, they may be responses to different aspects of what cause them, and so they remain ambiguous. [ibid: 19]

This helps to suggest that the form of triangulation involved is not merely of a primitive sort. Davidson does not attempt to reduce meaning-laden notions – such as intensions – to merely extensional causal relations even as augmented by primitive triangulation. Hence the form of triangulation relevant concerns explicitly a linguistic setting.

[S]ince no non-intensional magic trick will do to fix the causes, and hence the meanings, of one’s thoughts and utterances, only those producing the thoughts and utterances could achieve this feat. And they could achieve it only by having the concept of objectivity and triangulating linguistically with others. [ibid: 20]

In other words, the triangulation argument proper presupposes the intensionally fine grained linguistic resources of both field linguist or teacher and student (or child). Responses as to what is natural by the linguist are informed by their own conceptual or linguistic abilities.

At this point in her exegesis, Verheggen’s earlier claim that the triangulation does not address two distinct elements in two distinct applications, but rather a single dual-faceted element, comes to the fore.

Most commentators and critics have concluded that there are actually (at least) two triangulation arguments to be unearthed in Davidson’s writings—one for the conclusion that triangulation is required to fix the meanings (i.e., propositional contents, on which more soon) of one’s thoughts and utterances, the other for the conclusion that triangulation is needed to have the concept of objectivity, which, for Davidson, is also needed to have a language and thoughts (in addition, that is, to the obvious requirement that meanings be fixed). [ibid: 11]

Verheggen argues that having a concept of objectivity is an essential component of having a language or thought. And hence, the role of the triangulation argument is to show that outside this structure of actual interpretation by another, no one could count as a speaker, thinker or possessor of concepts.

[A]ccording to Davidson, neither non-linguistic creatures nor solitaires could have thoughts since possession of these requires possession of the concept of objectivity, which in turn requires linguistic triangulation. [ibid: 21]

Here, the invocation of the Wittgensteinian distinction between being right and merely seeming right, invoked by Davidson in the first half (though less in the second half) of ‘The second person’, plays an important role in Verheggen’s reconstruction of the argument. I will quote her argument at some length.

[Davidson] writes: “by yourself you can’t tell the difference between the situations seeming the same and being the same” (Davidson 1994, 124).36 Whenever he makes this point, Davidson mentions Wittgenstein to back him up, but he never himself defends it in any detail. Why exactly, then, could the solitaire not be in a position to have the concept of objectivity? Recall the predicament she is in: no matter how regular her responses to the environment may be, they may still be responses of different kinds; they may be responses to different aspects of the environment. Thus she must be the one to tell, objectively, at least for some of the causes of her responses, which causes are the same as which, which of her responses are correct. But how is she supposed to draw such an objective line between what seems to her to be the same cause, or the correct response, and what is in fact the same cause, or the correct response? [ibid: 22]

For the solitaire’s responses to her environment to count as expressive of a concept of some specific aspect of the environment, there must be a difference between things seeming the same for her and really being the same. But, according to Davidson, no such distinction is available. Note that Davidson himself denies that the distinction needs to amount to a ‘verification’ (for example, conclusive evidence that something in the environment really instances the same aspect). Merely supporting or undermining reasons would have to be sufficient (in context) for drawing the distinction given that conclusive verifications are hard to find. (Better: such reasons would need to be sufficient to meet the specific necessary condition whether or not they are sufficient across the board.) Are there any resources for calling an initial judgement into doubt or providing it independent justification even if not conclusive? Verheggen continues:

Well, it may be replied, she might have the following kind of experience: As a result of regularly finding blackberries in some particular bush, she one day experiences frustration upon not finding any in that bush. And it may be argued that experiences of this kind put her in a position to have the concept of objectivity since by hypothesis she realizes that her belief about what is in the bush is false and thus that there is a distinction between what she believes to be the case and what is the case. Now, strictly speaking, by assuming that the solitaire has beliefs, this scenario begs the question against Davidson, if he is right to say that only those who have the concept of objectivity can have beliefs with determinate contents. Thus what we have to imagine here is some experiences of the solitaire putting her in a position to possess both... [ibid: 22]

This last charge of question begging must be wrong. Davidson claims that the solitaire cannot have a concept of objectivity - or cannot have a concept of an objective feature of the world - because of the failure of a necessary condition on concept possession. It is thus perfectly in order for someone who denies this to assume, for the time being, concept possession and then test to see whether the necessity claim can be sustained. One cannot argue that Davidson must be right because any attempt to sketch an alternative starts by disagreeing with him! That is despotism rather than philosophy. 

What would be question begging would be defending an out and out sufficiency claim – for example via a reductionist account of concept possession – by starting with assuming concept possession. Still, has Verheggen shown that the solitaire cannot draw a distinction between being right and merely seeming right? She continues, now putting scare quotes round the word ‘thought’ thus:

But then what we have to imagine is the solitaire being able to notice that her present and her former “thoughts” do not match and to decide objectively which way to go. This in turn entails the question, what reason is there to think that she is having a thought about the same bush? Perhaps she is “thinking” that she passed the fruity bush, or that she took the wrong turn, or whatever. The point is that, whatever she is “thinking”, be it that it is the same bush or that it is not, will be correct, according to her. She does not have to draw one conclusion rather than another. However she draws the line between correct and incorrect responses that will be right to her. There is no way she can do this objectively. [ibid: 22]

Verheggen’s worry starts from the idea that there is more than one theory of what has happened if the solitaire discovers her belief about the fruit bearing aspect of one bush is frustrated. Adding to this the fact that the solitaire is alone, Verheggen concludes that any judgement she makes about which is the more plausible explanation will collapse into merely what seems right to her. It will be impossible for her to find that she is wrong in favouring a theory.

The fact that there is more than one theory of what has happened is, however, merely an instance of the familiar underdetermination of theory by data and consequent holism in theory testing in science which is part of Davidson’s Quinean heritage. I suggest it is the reason that Davidson denies that a being right versus seeming right distinction requires a conclusive verification. In science, as Quine emphasised, conclusive verifications are not, in principle, to be had. 

Must the solitaire, in virtue of being alone, be in an even worse position than simply lacking conclusive verifications such that the distinction between being right versus seeming right cannot even be drawn? This would be a surprising conclusion to draw from underdetermination and holism, given that they are ubiquitous. Surely not. We can equip the solitaire with further resources such as a map of the wood with the distances in paces between the various trees outlined. (To repeat, this is not begging the question. The onus of proof lies with Davidson and Verheggen to show why a necessary condition fails in order for them to defend their proscription on solitary thought.) Now, even with such a map, there is no conclusive verification of what has gone wrong if a belief about fruit on a bush has failed. Perhaps that bush does not always have fruit or perhaps the solitaire has got lost and is looking at a different bush. But equipped with the map, these different cases admit of different predictions and hence ways of justifying – albeit not amounting to conclusive verification – or undermining a judgement. Even having settled on an explanation, the solitaire may later come to discover reasons to think she was wrong.

(An aside: in the parallel debate about Wittgenstein, we’re not situated in a wood eating fruit. We are making judgements about almost ineffable sensations! No one takes on Robinson Crusoe any more!)

In any case, it had better not be the case that holism - by contrast with foundationalism and conclusive verification - is enough to rule out objectivity and collapse the distinction between being and merely seeming right. If so, Quine’s picture of science is the first casualty.

Verheggen suggests that there is a difference, however.

But the situation changes dramatically if the solitaire starts triangulating. Thus Davidson continues the above-quoted passage:

If you and I each correlate the other’s responses with the occurrence of a shared stimulus, however, an entirely new element is introduced. Once the correlation is established it provides each of us with a ground for distinguishing the cases in which it fails. (Davidson 1994, 124)

There is space for the concept of error, which appears when there is a divergence in normally similar reactions. (Davidson 2001b, 12) [ibid: 22-3]

What changes dramatically for the triangulator is that she is interacting and so can settle with another person, rather than just with herself, the ways in which perspectives on a given event or state of affairs may diverge. As long as the responses of triangulators do not diverge, they presumably cannot yet objectively distinguish between what seem to them to be the same, or the correct, responses and what are the same, or the correct, responses to their environment. But if their responses diverge, the distinction is “forced” upon them, as Davidson once put it (Davidson 1975, 170). It is forced upon them because they have no choice but to negotiate, so to speak, the resolution of the divergence. Thus, suppose that they have been picking blackberries in a particular bush and one day they come across a bush that is empty of blackberries. One of them insists that it is the same bush now empty of blackberries; the other maintains that it is a different bush because they took a wrong turn. How they settle the dispute cannot be dependent on one or the other interlocutor but must be the result of genuine communication between them. Indeed, we might say that whereas the solitaire “communicates” with herself regardless of how she settles the matter under dispute, interpersonal communication could not succeed if it were left to one or the other interlocutor to decide which way to go. Communication requires them to agree, or at least to agree to disagree. And, even in order to disagree, they have to agree on how their utterances are to be understood by each other, something that can only be settled, ultimately, on the basis of regular connections between their utterances and their environment. [ibid: 23]

Sadly, this passage leaves it far from clear why linguistic triangulation introduces an extra ingredient. Verheggen quotes Davidson as saying that a distinction between seeming and actually being right is forced on both speakers. But it seems equally forced on the solitaire who finds no fruit where she expected them. She too must determine which of the available competing theories is to be preferred. Why does the presence of an extra speaker make this any different? What epistemic difference does communication - even genuine communication - with another speaker make over and above the solitaire's resources of, for example, consulting maps or diaries, looking at the nearby bushes, looking again at this bush, perhaps examining the ground for pips or tell-tale signs of bird activity, drawing up rival theories and sifting evidence holistically? (It is almost as though at this point magic enters the picture. Perhaps this is what Derrida calls the ‘Myth of Presence’?)

Verheggen later attempts a further clarification. She says:

[A] solitary person could recall that her attitudes towards objects have not always been what they now are and so come to wonder what they should be next time around. The problem here, of course, is that a solitary person would need already to have acquired the concept of objectivity before she could imagine or recall such things. She would need already to understand that differing utterances or actions could be contradictories, not just differing noises or movements but actually competitors for the same logical space. Davidson is hoping to explain how people come to understand this by pointing to their experiences of triangulation, whereas his critics too often simply presume that people understand this and hence beg the question against him. Either that, or they simply assert that there could be other explanations without saying what they could be—in which case they avoid begging the question against Davidson only because they don’t answer it themselves. [ibid: 131]

Again the charge of begging the question is simply a mistake. Davidson has announced the contentious claim that a necessary condition can be satisfied by triangulation but not by the solitaire and thus it is entirely in order to test this by seeing whether any contradiction emerges on the preliminary assumption that the solitaire is a thinker and examining how they can meet the condition on objectivity that Davidson has argued is necessary. To repeat, this is how he treats triangulators.

But what difference would adding a second person make if - let us briefly assume - one did have some additional (non-Davidsonian) reason to deny that the solitaire possesses a concept? Verheggen implies that the solitaire does not ‘understand that differing utterances or actions could be contradictories, not just differing noises or movements but actually competitors for the same logical space’. But if she does not, what help is adding a further speaker into the mix? What makes their noises or movements available to her as expressive of ‘competitors for the same logical space’ rather than yet more noises and movements in the Wild Wood? How does adding two solitaires together make the difference? 

(What if the now-triangulating, ex-solitaires only communicate in writing such that each produces the same maps and diaries and competing theories that each had alone drawn up? What if their discussion of rival theories is not bald competing assertion but open minded discussion? Perhaps each takes it in turn to speak for the rival merits of the competing theories? Why then is two different from one? One possible difference is a lack of joint singular reference, joint attention. But as the next quote concedes, mere joint singular reference is not the key point. If it is, can we have the argument please?)

A little later Verheggen offers a significant clue.

To begin with, it must be stressed again that Davidson’s goal is “not to explain in detail how the process [i.e., the first entry into thought and language] works… but to indicate how the triangular arrangement makes the process possible” (Davidson 2001c, 293). The question is thus whether Davidson has succeeded in doing the latter. Here, I believe that what needs emphasizing is the difference between the solitaire’s and the triangulator’s positions…. And the only way to do this is to remind ourselves, once more, of what calls for a non-reductive, and thus circular, account to begin with. It is the appreciation that primitive triangulation leaves the causes, and hence the meanings, of triangulators’ responses to their environment indeterminate. Triangulators are no better off than solitaires at that stage… [ibid: 34-5]

Primitive – ie non-linguistic triangulation – is no better off than the solitaire. So the key difference to the necessity claim comes with the move from primitive to linguistic triangulation. How does this move underpin the necessity claim concerning objectivity and the difference between being right and merely seeming so?

[Primitive] [t]riangulators are no better off than solitaires at that stage—hence the need for would-be thinkers and speakers to have the concept of objectivity and the leap into the intensional realm. It seems to me that the motivation for this need is unobjectionable if the verdict on primitive triangulation is right. Then the question becomes why [linguistic] triangulation is needed to have the concept of objectivity. Just as there might be room for there being determinate causes of her responses for the solitaire, so there might be room for her to become aware of the concept of objectivity. But, as we have seen, this is precisely what Davidson denies. And he does this, as I have tried to show, by articulating a significant difference between the solitaire and the triangulator, which is that only the triangulator is obliged to consider her interlocutor when settling a dispute about diverging responses. [ibid: 34-5]

Now as Verheggen is keen to stress, Davidson does not offer a reduction of the intensional and semantic to the non-intensional. Linguistic triangulation presupposes that the triangulators are thinkers and speakers. That does not undermine its potentially elucidatory role. It may, for example, help to suggest how the distinction between being and seeming right is operationalised. (In effect, this is what I have been trying to do for the solitaire: assume concept possession and then look to check that a condition on objectivity can be met.) But Davidson and Verheggen want it to do something more: to rule out the solitaire as a thinker and concept possessor. If that is the aim then simply granting that those involved in linguistic triangulation are thinkers while denying this status to the solitaire is indeed simply question begging. What is the difference that makes the difference? Davidson and Verheggen wish to grant thinker status to some and deny it to others but they need to earn the right to the distinction. Granting merely pro tem is easy.

But it is almost as though Verheggen herself realises this argumentative lacuna when she offers the following summary of the difference between the two cases: ‘there is a difference between the solitaire and the triangulator: only the latter triangulates!’ [ibid: 35]. Well we know that. But no attempt, sadly has been made to say what the significance of this distinction comprises.

(My debt to Simon Blackburn’s 1984 paper ‘The individual strikes back’ will be obvious. Indeed, what is so odd about this Davidsonian debate is that nothing much - aside from a quick reference to Kripke - has been learnt from the extensive debate about communitarian readings of Wittgenstein.)


Blackburn, Simon. 1984. “The Individual Strikes Back.” In Miller, Alex and Crispin Wright, eds. 2002. Rule-Following and Meaning. Montreal and Kingston: McGill-Queen’s University Press.

Davidson, Donald. 1994. “The Social Aspect of Language.” In Davidson, Donald. 2005. Truth, Language, and History. Oxford: Clarendon Press.

Davidson, Donald. 2001a. Subjective, Intersubjective, Objective. Oxford: Clarendon Press

Davidson, Donald. 2001b. “Externalisms.” In Kotatko, Petr, Peter Pagin and Gabriel Segal, eds. (2001) Interpreting Davidson. Stanford: CSLI.

Myers R.H. and Verheggen, C. (2016) Donald Davidson’s Triangulation Argument A Philosophical Inquiry by Robert H. Myers and Claudine Verheggen New York : Routledge