There is no justification either for the idea that Greek science was built up solely by more or less lucky guesswork, instead of by observation and experiment. The nature of our tradition, which mostly consists of _Placita_—that is, of what we call “results”—tends, no doubt, to create this impression. We are seldom told why any early philosopher held the views he did, and the appearance of a string of “opinions” suggests dogmatism. There are, however, certain exceptions to the general character of the tradition; and we may reasonably suppose that, if the later Greeks had been interested in the matter, there would have been many more. We shall see that Anaximander made some remarkable discoveries in marine biology, which the researches of the nineteenth century have fully confirmed (§ 21), and even Xenophanes supported one of his theories by referring to the fossils and petrifactions of such widely separated places as Malta, Paros, and Syracuse (§ 59). This is enough to show that the theory, so commonly held by the earlier philosophers, that the earth had been originally in a moist state, was not mythological in origin, but was based on, or at any rate confirmed by, biological and palaeontological observations of a thoroughly modern and scientific type. It would surely be absurd to imagine that the men who could make these observations had not the curiosity or the ability to make many others of which the memory is lost. Indeed, the idea that the Greeks were not observers is almost ludicrously wrong, as is proved by two simple considerations. The anatomical accuracy of Greek sculpture bears witness to trained habits of observation, and those of the highest order, while the fixing of the seasons by the heliacal rising and setting of the stars shows a familiarity with celestial phenomena which is by no means common at the present day.[43] We know, then, that the Greeks could observe well in matters affecting agriculture, navigation, and the arts, and we know that they were curious about the world. Is it conceivable that they did not use their powers of observation to gratify that curiosity? It is true, of course, that they had not our instruments of precision; but a great deal can be discovered by the help of very simple apparatus. It is not to be supposed that Anaximander erected his _gnomon_ merely that the Spartans might know the seasons.[44] Footnote 43: These two points are rightly emphasised by Staigmüller, _Beiträge zur Gesch. der Naturwissenschaften im klassischen Altertume_ (Progr. Stuttgart, 1899, p. 8). Footnote 44: The gnomon was not a sundial, but an upright erected on a flat surface, in the centre of three concentric circles. These were drawn so that the end of the gnomon’s shadow touched the innermost circle at midday on the summer solstice, the intermediate circle at the equinoxes, and the outermost circle at the winter solstice. See Bretschneider, _Die Geometrie vor Euklid_, p. 60.