Romeo loves Juliet. He tells her so. He spends as much time with her as he can, and when he can't be with her he sends her roses and emails. Naturally he spends a lot of time thinking about her. At the moment he is wondering whether to buy her a ring, although he has no particular ring in mind.

We have no trouble understanding how Romeo's roses and emails reach Juliet. But how can his thoughts get to her? How is it possible for a purely physical organism to have thoughts which reach out into the world, and may even be about things that don't exist? You don't have to feel drawn to dualism to find intentionality mysterious. We have already glanced at some of the main approaches to these questions; in this chapter we will go deeper. To start with we will look at two strongly opposed ways of explaining what it is for Romeo to think about Juliet.

Two opposed explanations of intentionality

If you had asked Plato, Aristotle, Locke, Hume or Kant, or for that matter the Wittgenstein of the Tractatus, they would have replied that to think about something involves having an “idea”, “impression”, or “representation” of that thing in your mind. To think about Juliet, Romeo must have an internal representation (idea, impression) of her. This “representation” is “mental”, “internal”, and of course real.