phenomenally, we can know no present, since it must be in the 'past' before our senses can complete the process of recording it, leaving only a suppositional past and future; noumenally there is no question of 'past' or 'future' but only a presence which knows neither 'time' nor 'space'.
'space' is here a concept which provides exteriorised objects with the extension necessary to render their appearance 'solid', i.e. perceptible tri-dimensionally as objects, and in spatial relation to other objects, just as 'time' is their equally necessary extension in duration. time is, therefore, an extension of space in duration, and so a further direction of measurement. space-time as a single concept then utilises four dimensions, three spatial and one temporal.