Cleinias has returned together with the other participants from the discussion recounted in the Laws, and wants to know what type of knowledge predisposes man to wisdom (ποιεῖν πρὸς φρόνησιν). The Athenian begins his discussion by saying that the human race is neither blessed nor happy, for life is hard by design. No sooner do the toils of growing up and getting educated end, that old age begins (973d-974a). And yet, he will attempt to answer by first going through the list of existing sciences, like agriculture and medicine, to see if any could be called wisdom. The Athenian finds them all wanting, as they all have to do with opinions rather than truth (976a-b). He then moves to work by elimination, and see if there is a science that by removing it mankind is rendered thoughtless. Answering this question is much easier: the science of numbers (τὸν ἀριθμὸν δοῦσα), which is so important it must have been given by God (976e), however one might conceive of him (977b). Everything in nature moves through discrete phases, like the waxing and waning of the moon, and so, everything can be understood through numbers.