Henri Bergson saw first of all that Spencer was led to his sceptical view because mathematical physics methodically abstracts from the real experience of time. Time passing twice as fast would change nothing in calculations, for the scientist would count the same number of unities of time in the movement whose temporal span is being measured. Immanuel Kant claims about number and time seem to have a strong and a weak version, depending on whether the view is that time is what is counted or that it is just necessary for the process of counting. Time quantified and mathematised is time spatialised: “it is to be presumed that time understood in the sense of a medium in which one distinguishes and one counts is merely space”. Space is a principle of quantitative difference, of quantitative multiplicity. As Bergson writes, “we know two different orders of reality: one, that of sensory qualities, is heterogeneous, the other, that of space, is homogeneous.