| Besides the mere fact of existence, then, there must be something by means of which A determines the position of B in time and, conversely, B the position of A; because only under this condition can substances be empirically represented as existing contemporaneously. |
| Now that alone determines the position of another thing in time which is the cause of it or of its determinations. |
| Consequently every substance (inasmuch as it can have succession predicated of it only in respect of its determinations) must contain the causality of certain determinations in another substance, and at the same time the effects of the causality of the other in itself. |
| That is to say, substances must stand (mediately or immediately) in dynamical community with each other, if coexistence is to be cognized in any possible experience. |
| But, in regard to objects of experience, that is absolutely necessary without which the experience of these objects would itself be impossible. |
| Consequently it is absolutely necessary that all substances in the world of phenomena, in so far as they are coexistent, stand in a relation of complete community of reciprocal action to each other. |
| The word community has in our language [Footnote; German] two meanings, and contains the two notions conveyed in the Latin communio and commercium. |
| We employ it in this place in the latter sense--that of a dynamical community, without which even the community of place (communio spatii) could not be empirically cognized. |
| In our experiences it is easy to observe that it is only the continuous influences in all parts of space that can conduct our senses from one object to another; that the light which plays between our eyes and the heavenly bodies produces a mediating community between them and us, and thereby evidences their coexistence with us; that we cannot empirically change our position (perceive this change), unless the existence of matter throughout the whole of space rendered possible the perception of the positions we occupy; and that this perception can prove the contemporaneous existence of these places only through their reciprocal influence, and thereby also the coexistence of even the most remote objects--although in this case the proof is only mediate. |
| Without community, every perception (of a phenomenon in space) is separated from every other and isolated, and the chain of empirical representations, that is, of experience, must, with the appearance of a new object, begin entirely de novo, without the least connection with preceding representations, and without standing towards these even in the relation of time. |
| My intention here is by no means to combat the notion of empty space; for it may exist where our perceptions cannot exist, inasmuch as they cannot reach thereto, and where, therefore, no empirical perception of coexistence takes place. |
| But in this case it is not an object of possible experience. |
| The following remarks may be useful in the way of explanation. |
| In the mind, all phenomena, as contents of a possible experience, must exist in community (communio) of apperception or consciousness, and in so far as it is requisite that objects be represented as coexistent and connected, in so far must they reciprocally determine the position in time of each other and thereby constitute a whole. |
| If this subjective community is to rest upon an objective basis, or to be applied to substances as phenomena, the perception of one substance must render possible the perception of another, and conversely. |
| For otherwise succession, which is always found in perceptions as apprehensions, would be predicated of external objects, and their representation of their coexistence be thus impossible. |
| But this is a reciprocal influence, that is to say, a real community (commercium) of substances, without which therefore the empirical relation of coexistence would be a notion beyond the reach of our minds. |
| By virtue of this commercium, phenomena, in so far as they are apart from, and nevertheless in connection with each other, constitute a compositum reale. |
| Such composita are possible in many different ways. |
| The three dynamical relations then, from which all others spring, are those of inherence, consequence, and composition. |
| These, then, are the three analogies of experience. |