"It is true that the accurate determination of the risings and settings of the stars does demand scientific work, but not so the observation of the visible risings and settings. Primitive man rises and goes to bed with the sun. When he gets up at dawn and steps out of his hut, he directs his gaze to the brightening east, and notices the stars that are shining just there and are soon to vanish before the light of the sun. In the same way he observes at evening before he goes to rest what stars appear in the west at dusk and soon afterwards set there.

Experience teaches him that these stars vary throughout the year and that this variation keeps pace with the phases of Nature, or, more concretely expressed, he learns that the risings and settings of certain stars coincide with certain natural phenomena. Here, therefore, there lies ready to hand a means of determining the time of the year, and one which is ideed much more accurate than a method depending on a reference to the phases of Nature."

"To create constellations in which terrestrial objects, animals, and men are arbitrarily seen requires no considerable degree of imaginative power. The Pleiades however form themselves into a group without any aid from this imagination, and can without difficulty be recognized as such.

It is because they are easy to recognize immediately that the observation of these stars plays so important a part. A similar case is that of the Magellanic Clouds, which, where they are visible, belong to the best known phenomena of the heavens, and we may also compare the dark starless patches which so largely occupy the attention of primitive peoples, although neither of these two phenomena is used in determining time, since neither can be observed at the favourable moment, viz. the twilight."

(Nilsson)