The inside and outside views of life

Biology is, better than anything else, about existence in time. Hence biological reality cannot be defined without reference to a temporally situated observer. The coupled or detached character ter of this observer (with respect to the own time variable of the system) provides a link between the observer and the observed. This connections delimits the kinds of scientific descriptions that can be given at all by an observer. In particular, two fundamentally different forms of description, corresponding to different epistemological attitudes and different philosophies of science: called endo- and exo-physics, can be distunguished. Two old puzzles. the Omniscience Problem (illustrated here on the example of Internal Chemistry) and the Chameleon Problem (originally an argument against philosophical functionalism) are reconsidered in the light of these distinctions. As application, the question, in what sense computer models of life can be suitable for studying life, is examined.