There is, as already mentioned, the rhythmic occurrence of the seasons in connexion with the varying relative positions of earth and sun. Alongside this we may put the rhythm of the tides, coincident with the phases of the moon. Just as the solar rhythm manifests in an alternating rise and fall of the saps in the plants, so also does the lunar rhythm.⁴ (Note how this fact actually vitiates the usual explanation that the tidal rhythm of the sea is caused by a gravitational pull exerted by the moon's body on the oceanic water.) In neither instance is the change of position of the relevant cosmic body - in our examples that of the sun or moon in relation to the earth - the 'cause' of the corresponding rhythmic events on the earth. Together with all other rhythmic events of equal periodicity, it is itself the effect of the activity of a force-sphere constituting the cosmic realm to which the relevant planetary body belongs.