Triangulation and the common cause

There is another, related problem for Davidson in the idea that a creature without a language (or with merely a private language) could have thought. This problem concerns the identification of what features of the environment such a creature is reacting to (and that his beliefs or utterances could be about). We would have to infer what the creature is reacting to on the basis of its behaviour, but the evidence is underdetermined in two dimensions: both in terms of how distal the cause of the creature’s response is and in terms of what its width is. In terms of how distal the stimulus is, the creature could be responding to anything, ranging from the sensory stimuli to objects and events (as we identify them) in its environment (and anything beyond in space and time). In terms of width, it is unclear, even if we could settle how distal the stimulus of the creature’s response is, how wide the cause is; in other words, even if we could settle what the beginning of the causal chain is that elicited the creature’s response (and hence how far away the object of the creature’s response is), the question remains how wide the causal chain is. A further problem is that in case of a solitary creature there is no answer to the question which responses of the creature count as being of the same type, and hence which responses are responses to the same thing for the creature. Davidson thinks that the question as to what the stimulus is (and what counts as a reply of the same type) can only be answered if the creature interacts with another creature, and if a common cause of their responses can be identified. He uses the metaphor of triangulation to illustrate this.41 Davidson conceives of triangulation in the following way. Two (or more)

39_{Evolutionary phenomena are often also explained in teleological terms.} 40

Cf. RA, pp. 101-102 and ET, p. 128.

41

triangulating creatures observe each other’s responses to objects and events (and whatever else there is to ontology) in their environment. Let the tri- angulating creatures be A and B. Creature A observes a causal connection between the presence of similar objects and events in the environment and similar responses given by creature B when such objects and events are present. Creature B, in turn, is able to correlate similar responses of crea- ture A with the presence of similar objects and events. Further, creature A and B respond to each other’s responses. If creature A produces the type of response previously associated by creature B with certain conditions, crea- ture B may react to creature A’s response as if those conditions obtain (even if it did not itself observe them) (and vice versa).42

If there were just one creature responding to its environment, Davidson argues, there is no way to settle what it is responding to. Once we have the triangular interaction described above, we can identify where the causal chains from the triangulators’ skins into the world intersect, and we can identify a common cause, something they are both responding to.43 In the triangular setting there is also an intersubjective criterion as to which re- sponses of a creature are of the same type, and are therefore to be considered as responses to the same type of stimulus: this is determined by the other creature’s recognizing them as being of the same type and associating them with conditions in the environment (which could be manifested by the other creature’s responding to those responses in the way it would respond if it observed itself that those conditions obtained).

For the kind of triangulation described above to amount to linguistic communication more is needed than mere coordination of responses: propo- sitional content must be conveyed between the triangulators. In fact, in our description we already assumed that this happens by using intentional notions, like ‘observe’ and ‘associate’. Triangulationwithout the communi- cation of content (creatures reacting to stimuli and to each other’s reactions to stimuli in a coordinated way) is a process that Davidson thinks occurs widely among animals.44 In case of such ‘primitive’ triangulation, we can at least—to some extent—identify common causes, but the process is not sophisticated enough to ascribe thought or language to the triangulators. For Davidson it is no more than a sophisticated mechanistic process, in which the creatures involved manifest fine-grained dispositions not merely in their reactions to the environment, but also in their reactions to each other’s reactions.

Davidson suggestion is, however, somewhat speculatively, that even though thought and language play no role in such a process, such a process is the behavioural framework needed for thought and language to arise. David-

42

Cf. STL, pp. 138-141.

43

Cf. TVK, p. 212.

son thinks of primitive triangulation as creating space for (and being part of) a more sophisticated triangulation: linguistic triangulation. For the creatures to triangulate linguistically, they must have the concepts related to objectivity: truth, belief, error, etc. Primitive triangulation ‘provides the framework’ for the idea of the concept of error.45 In a tentative way Davidson gives the following scenario to illustrate this. If a creature has associated another creature’s response to certain conditions (association, of course, presupposes intentionality), and at some point the other creature produces the response without the expected conditions’ materializing, the notion of error may occur: the former creature may realize that the latter is mistaken. If it does so, the creatures succeeded to communicate content, and this requires language. Davidson finds it a natural assumption, on the basis of these considerations, that grasping the concept of truth (and the other concepts related to objectivity) and communicating content can only arise simultaneously. These notions are mutually dependent. Therefore, thought and language are mutually dependent.46

Davidson sometimes describes the triangular setting as a language learn- ing situation, which suggests that he thinks it points at some basic truth about what is needed to acquire a language.47 Triangulation so conceived of involves a teacher, a child, and a shared world inhabited by objects and events. While triangulating, the child observes the teacher reacting to classes of objects and events it deems similar. The child is able to correlate those classes of objects and events with similarity classes of the teacher’s responses. The child will, following the teacher in this, use similar responses to reply to similar observations. The child need not use the same responses as the teacher, but for learning to be successful the teacher must be able to classify the child’s responses in types. The teacher will reward or punish the child, depending on whether or not the child responds in an interpretable way to the objects and events, i.e. according to how the teacher would classify those objects and events. That the teacher and child are responding tothose dis- tal objects and events (and not for example to retinal images) is so because those objects and events are the only common cause for teacher and child: here the causal chains (or, as Davidson calls them, ‘the lines of thought’)48 from the teacher’s and the child’s skin into the world cross, and this is what teacher and child take to be the causes of their responses. A precondition for triangulation is that child and teacher (roughly) share their sensitivity to some rather than other environmental conditions and have the same idea of which stimuli and responses are of the same type.

45 Cf. STL, pp. 140-141. 46_{Cf. STL, p. 141.} 47 Cf. SP, p. 120. 48_{Cf. SP, pp. 120-121.}