The basic characteristic of human existence.

In physics, the theory of [special] relativity introduced the position of the observer as a theme of science. Yet physics, as such, is unable to say what this "position of the observer" means. It obviously refers to what we touched on by saying: I am here at any time. In this being-here, the bodiliness of the human being always comes into play. In the area of microphysics, the act of measuring and the instrument themselves interfere with comprehending the objects during experimentation. That means that the bodiliness of the human being comes into play within the "objectivity** of natural science. Does this only hold true for scientific research, or is it true here precisely because in general the bodying forth of the human being's body co-determines the human being's being-in-the-world.

P. 93

Galileo had already postulated relativity (no absolute space or time), but Cartesian absolute coordinates worked (the math calculated) for Newton, so relativity was forgotten. Until 1905, when Einstein explained that given that the speed of light is absolute, relative to the body making the measurement, then space and time had to be relative for every body. Therefore, embodied Dasein's space-time, human being's being-in-the-world, is appropriated by Dasein, and not a feature of the natural world.   ¶ 12:13 PM