T 2.3.7.5

The cause of this phænomenon must evidently lie in the different properties of space and time. Without having recourse to metaphysics, any one may easily observe, that space or extension consists of a number of co-existent parts dispos'd in a certain order, and capable of being at once present to the sight or feeling. On the contrary, time or succession, tho' it consists likewise of parts, never presents to us more than one at once; nor is it possible for any two of them ever to be co-existent. These qualities of the objects have a suitable effect on the imagination. The parts of extension being susceptible of an union to the senses, acquire an union in the fancy; and as the appearance of one part excludes not another, the transition or passage of the thought thro' the contiguous parts is by that means render'd more smooth and easy. On the other hand, the incompatibility of the parts of time in their real existence separates them in the imagination, and makes it more difficult for that faculty to trace any long succession or series of events. Every part must appear single and alone, nor |can regularly have entrance into the fancy without banishing what is suppos'd to have been immediately precedent. By this means any distance in time causes a greater interruption in the thought than an equal distance in space, and consequently weakens more considerably the idea, and consequently the passions; which depend in a great measure, on the imagination, according to my system.