161. Since times in like manner are settled and constant, they are also proper to nature, for the duration of a day is constantly of twenty-four hours, and the period of a year is constantly of three hundred and sixty-five and a quarter days. The very states of light and shade, and of heat and cold which make these periods vary, are also constant in their recurrence. The states which recur daily are morning, noon, evening and night, and those which recur yearly are spring, summer, autumn and winter. The states of the year also constantly vary the states of the days. All these states are also dead, because they are not states of life as in the spiritual world. For in the spiritual world there is continuous light and continuous heat, the light corresponding to states of wisdom, and the heat to states of love with the angels; wherefore the states of these are living.