I have been perusing an old book by Simon Blackburn called Spreading the Word. In it, Blackburn has a very helpful little section describing the relationship between mind, language, and the world in the form of a triangle the corners of which are connected to one another by theories. The mind corner is connect to the world by a theory of knowledge and connected to the language corner by a theory of meaning. The world corner is connected to the language corner by a theory of truth.
The idea is that one chooses a corner from which to develop theories for the sides. The task then becomes ensuring that one’s corner contains a sufficient factual basis for all the three theories involved (meaning, knowledge, truth).
Say you pick the world. The question is: what facts about the world provide the materials for your theories of meaning, truth, and knowledge? Say you pick the human mind. One would have to explain how sentences in natural languages have meanings, how those meanings can be true or false, and how we could rely on our mental faculties to arrive at those truths thereby rendering us knowledgeable.
The history of philosophy could be explained by showing how various philosophers chose a corner. Blackburn writes:
At a given time, in a given philosophical tradition, one or another points of this triangle will appear prominent. That point will represent the primary source of understanding, so that the natural direction of enquiry is to use that knowledge to aim at conclusions about the other elements.
For example, Plato chose the world as his corner. If one takes a Platonist approach to abstract objects, one might suggest that propositions are abstract objects with truth values granted in virtue of their correspondence with facts or states of affairs in the world. One could then answer the question of meaning by suggesting that propositions are the contents of indicative sentences. One’s theory of knowledge would then be beholden to beliefs that are gained through ‘grasping’ propositions. In contrast, Cartesian views focus on the mind as the location of explanation. The ‘linguistic turn’ was a ‘turn’ to the language corner. Positivists and metaphysicians vie for different ways in which the ‘world’ corner provide sufficient information for their theories. The tricky part is making sure that all three theories are adequately taken care of.
The more I study philosophers who pick corners, the more I am convinced that naturalism is false. Naturalistic philosophers tend to load a corner with too much weight expecting it to do all the work. Often, in attempting to offer a theory for one side, the construct theories that are supposed to handle two sides at once. For example, Jerry Fodor tries to construct a theory of meaning based on a causal theory of knowledge. His corner is the mind. According to Fodor, the mind contains innate ‘protoconcepts’ and a language of thought. When asked how one knows the meanings of sentences and the senses of words, he replies that objects in the world cause concepts in the mind. Somehow a concept is supposed to ‘lock’ onto a thing in the world. The same goes for the meanings of sentences, which he thinks of as sentences in a language of thought (or mentalese).
The trouble with Fodor’s view is that he relies on only one side to do all the work. The relationship between the world and the mind is all there is. Thus, it must bear all the weight. But doing so leaves a few unanswered questions: how is it that the lock occurs so sweetly? How can we be sure that the right thing in the world locks onto the right concept? And even if they do so, it is difficult to see why without appealing to something decidedly non-naturalistic such as intentional design. Further, I just can’t see how a thing causing a concept in the mind explains how we actually think about concepts. This is because, according to Fodor, all what’s in the mind is symbolic. The mind does not grasp abstract entities; rather it is populated by symbols forming a language. But one needs more than the symbol for, as Laurence BonJour points out, “merely having such thought-symbols present in my mind (or brain) in itself gives me no awareness of their content.”
Jerry Fodor, Psychosemantics: The Problem of Meaning in the Philosophy of Mind (Cambridge, MA: MIT, 1987).
Laurence BonJour, In Defense of Pure Reason: A Rationalist Account of A Priori Justification (New York: Cambridge University Press, 1998), 166.