"There is a marvelous ambiguity to the ego: on the one hand it is an ordinary part of the world, one of many things that inhabit it. It occupies space, endures through time, has physical and psychic features, and interacts causally with other things in the world: if it falls, it falls like any other body; if it is pushed, it topples over like any other thing; if treated with chemicals, it reacts like any living organism; if light rays hit its visual organs, it reacts electronically, chemically, and psychologically. 'I' am a material, organic, and psychological thing. If we were to take the self simply as one of the things in the world, we would be treating it as what can be called the empirical ego.

On the other hand, this very same self can also be played off against the world: it is the center of disclosure to whom the world and everything in it manifest themselves. It is the agent of truth, the one responsible for judgments and verifications, the perceptual and cognitive 'owner' of the world. When considered in this manner, it is no longer simply a part of the world; it is what is called the transcendental ego.

The empirical and transcendental egos are not two entities; they are one and the same being, but considered in two ways."
— Robert Sokolowski (Introduction to Phenomenology)