Intentionality is a relation between out thoughts and the contents of the world. It is supposedly intentionality that makes a thought about a dog different from a thought about a cat, because the thought about the dog is not related to the world in the same way that the thought about the cat is. Traditional theories hold that our thoughts are somehow “directed at” external objects by the intentional relation.
There are basically two ways of interpreting intentionality. The version that seems to be adopted by many philosophers I will call the non-casual version. Non-casual intentionality requires one to adopt externalism, the idea that the content of our thoughts (and the meaning of our words) is dependant on features of external reality. However, non-casual intentionality, no matter how it is defined is not real. You don’t have to take my word for it though, here is a simple experiment that you can do for see for yourself that non-casual intentionality is a hollow theory. A non-casual theory of intentionality would hold that our thoughts about something, say a soap bubble, participate in a relation between us and the soap bubble, and that it is this relation that gives them their meaning. So then blow a soap bubble and, before it disappears, place it behind a curtain, wait a few seconds, and then take it out. Sometimes it will have popped while it is behind the curtain and sometimes it will have remained intact. However no matter what actually happened your thoughts about the bubble weren’t affected (assuming you weren’t in direct contact with it). Your interactions with other people about the soap bubble, and your subjective awareness of your thoughts, are the same when the soap bubble stays intact and when it pops, given that you can’t see it. Thus there is no way to tell the difference between your thoughts in the case of the intact bubble and the case of the popped bubble. However surely the intentional relation must have undergone some change, since in some cases the object that it was direct it has completely ceased to exist. From this we can deduce that the intentional relation (defined in this way) cannot be a cause. (see here) However if it can’t be a cause then it makes no sense to say that it somehow affects or determines the contents of our thoughts, or allows one thought to be distinguished from another, since that would require casual power.
We might then attempt to save the intentional relation by defining it in a way that escapes this problem. Instead of saying that the intentional relation is between the object and our thoughts we might say that it is a special case of the casual relation between our current thoughts and the object at some time in the past. This certainly avoids the problem raised by the experiment above, since in both cases we perceived the soap bubble, and thus could say that our thoughts about the soap bubble were caused by it. Unfortunately this definition of intentionality has its own problems, specifically in dealing with fictional entities. A fictional entity, let’s say Darth Vader, can’t be the cause of any of our mental states, because he doesn’t exist. It is true that our mental states are causally affected by stories about Darth Vader, but we have the ability to think of Darth Vader himself, not just about certain movies that he was in. Since it is impossible to reasonably deny that people can direct their thoughts at such non-existent entities we must discard the casual version of intentionality as well.
What we need then is a theory that doesn’t lean so much on the external world, although it is impossible to deny that our thoughts about real objects are completely independent of the external world. This leads to my earlier theory about mental models, specifically that we build mental models of objects, and it is these mental models that provide our thoughts with content. Our mental models of real objects are connected to the external world by a causal relation, because the physical object has had a causal influence on our mental model of it. Mental models of fictional objects can be created as well of course, either by being exposed to fictional stories, or by pure imagination, but in the end the mental model that is created is “about” the fictional object alone, and not its inspiration. How then are our thoughts distinguished from each other? I would argue that it is reasonable to abstract thought as being an ordered set of references to mental models (or concepts). (Note: I am not saying that in individual thought possesses a temporal order among it parts, simply an internal ordering.) Thus, as you can see from the picture below, thoughts with different contents are easily distinguishable from each other (they will feel subjectively distinct) even though they have no direct connection with the external world.
It is important to remember that although the mental models are not directly connected to the world they are not independent of it either. The contents of the world influence our mental models, and our mental models influence how we interact with and classify the world.
Given this account how should we approach the similarities between the contents of thought among different people, a phenomena sometimes called “collective intentionality” (which is probably better called objective meaning or collective meaning)? I think that although collective intentionality may seem similar to how a thought is related to the world in the case of an individual (individual intentionality) they are really two distinct things (although not unconnected). Collective intentionality seems to be generated by a process of averaging the mental models of individuals (through communication). Words and concepts that have physical components end up being brought closer together (because communication about them is easier), and words that are tied to more abstract concepts tend to have more variation. However, like the idea of an average man, there is no one thing that can be pointed to as collective intentionality, it only makes sense in the context of a community, in which the individuals possess similar mental models. Any other conception of collective intentionality tends to end up as non-physical, and various problems reconciling our scientific knowledge of how the mind works with such a view inevitably result.
As you might be able to tell at this point I’m not a big fan of externalism, so expect more posts in the future that point out the flaws of externalism and defend internalism from criticisms.