(3) On investigating the character of our actual perception of space and time, it appears to contain two aspects, which we may call the quantitative and the qualitative. On the one hand, whenever we perceive space we perceive a certain magnitude of extension, whenever we perceive time we perceive a longer or shorter lapse of duration. Different spaces and different times can be quantitatively compared in respect of the bigness of the extension or the duration comprised in them. On the other hand, the percept of space or time is not one of mere extension or duration. It has a very different _qualitative_ aspect. We perceive along with the magnitude of the extension the _form_ of its outline. This perception of spatial form depends in the last resort upon perception of the _direction_ assumed by the bounding line or lines. Similarly, in dealing with only one dimension of perceived space, we never perceive _length_ (a spatial magnitude) apart from the perception of _direction_ (a spatial quality). The same is true of the perception of time. The lapses of duration we immediately perceive have all their special direction-quality; the “specious present” is essentially a simultaneously presented _succession_, _i.e._ a transition from before to after. It must be added that, in perceptual space and time, the directions thus perceived have a unique relation to the perceiving subject, and are thus all qualitatively distinct and irreversible. Direction in space is estimated as right, left, up, down, etc., by reference to axes through the centre of the percipient’s body at right angles to each other, and is thus for any given moment of experience uniquely and unambiguously determined. Direction in time is similarly estimated with reference to the actual content of the “focus of consciousness.” What is actually focal is “now,” what is ceasing to be focal is “past,” what is just coming to be focal is “future” in its direction.[142] This is perhaps the most fundamental and important peculiarity of the space and time of actual perception. All directions in them are unambiguously determined by reference to the _here_ and _now_ of the immediate experience of an individual subject. As a consequence, every individual subject has his own special perceptual space and time; Geometry and Mechanics depend, to be sure, on the possibility of the establishment of correspondences between these spatial and temporal systems, but it is essential to remember that, properly speaking, the space and time system of each individual’s perception is composed of directions radiating out from his unique _here_ and _now_, and is therefore individual to himself.[143]