EPISTEMOLOGY the conclusion that I am myself an idea? Lying in a deckchair, I have a range of visual impressions, from the toes of my shoes to the blurred outline of my nose By what right I pick out one of my ideas and set it up as owner of the others? Why have an owner for ideas at all? Here we come to a full stop If there is no owner of ideas, there are no ideas either; there cannot be an experience without someone to experience A pain is necessarily felt, and what is felt must have someone feeling it If so, there is something that is not yet my idea, and yet can be an object of my thought, namely myself Frege, like Descartes, brings scepticism to an end with a cogito, ergo sum But whereas Descartes’s ego was a non-ideal subject of thinking, Frege’s ego is a non-ideal object of thought Its existence refutes the thesis that only what is part of the content of my consciousness can be the object of my thought If there is to be such a thing as science, Frege maintained, ‘a third realm must be recognized’—a world in addition to the world of things and the world of ideas The ego, as the owner of ideas, is the first citizen of this third realm The third realm is the realm of objective thought The denizens of this realm share with ideas the property of being imperceptible by the senses, and share with physical objects the property of being independent of an owner Pythagoras’ theorem is timelessly true and needs no owner; it does not begin to be true when it is first thought of or proved (CP 362) Other people, Frege says, can grasp thoughts no less than I; we are not owners of our thoughts as we are owners of our ideas We not have thoughts; thoughts are what we grasp What is grasped is already there and all we is take possession of it Our grasping a thought has no more effect on the thought itself than our observing it affects the new moon Thoughts not change or come and go; they are not causally active or passive in the way in which objects are in the physical world In that world, one thing acts on another and changes it; it is itself acted upon and itself changes This is not so in the timeless world that Pythagoras’ theorem inhabits (PW 138) Few who have followed Frege down the path of Cartesian scepticism will follow him in the route he offers out of the maze His response to the challenge is no more convincing than Descartes’s own Both philosophers, having accepted a division between a public world of physical things and a private world of human consciousness, seek to rejoin what they have separated by appealing to a third world: the divine mind in the case of 159