"Time for us embraces a whole field of 'before and after', but Aristotle says: 'Before and after are involved in motion, but time is these so far as they are numbered' (Phys. 223a28). Elsewhere he defines time as 'the number of motion in respect of before and after', and he could seriously discuss the question whether there could be time without conscious and thinking beings; 'for if there could be no one to count, there could be nothing counted. ...If nothing can count but soul, and within soul mind, there cannot be time without soul, but only the substratum of time' (ibid. 219b2, 223a22)"