Abstract
The indexical sentence “I am here now” can be used any time and anywhere by anyone to say something true. Rather than yielding a special kind of infallible knowledge, this fact indicates that every speaker or thinker has a zero of an egocentric coordinate system at his disposal. Many idealist philosophers assume that this egocentric zero can be further reduced. The ability to make a de se-reference with the first person pronoun, they claim, need not involve spatiotemporal self-localization. The paper challenges this idealistic view. Starting from the observation that even Descartes’ cogito argument, which expresses a tensed truth, involves a dated mental episode, it is argued that nothing can exist in time without being in space. The paper concludes that the egocentric zero of orientation with its three mutually dependent elements (I, here, now) cannot be further minimized. Thinkers of I-thoughts must have a spatiotemporal position. They must be Strawsonian persons rather than Cartesian egos.