Descartes made a philosophical distinction between the substances of body and mind. He identified seperate essences for the mind and the body, describing the mind as a non-extended thinking thing, whilst the body a non-thinking extended thing. This distinction came to represent his substance dualism and this gave rise to his famous assertion of 'cogito ergo sum', meaning 'I think therefore I am'. Due to the seperation of substances, an implication would be that the mind can exist and survive outside of the body and that the body has no capacity to 'think'. This philosophical position is significant because it allows for a belief in life after death and that the immaterial soul and the material body can exist seperately.