History tells us that these kinds of 'knowledge what' explanations consisted principally in what we now call 'religious' beliefs. These in turn contributed further kinds of supposed 'knowledge how' by suggesting forms of interaction with aspects of nature, or the agencies that control nature, hoping to influence or propitiate them through ritual, prayer, and sacrifice. It is an interesting speculation that, as liturgical (religious, ritualistic) means of influencing nature came to be displaced by more practical and mundane expertise, so the interest in effecting control transferred itself from nature to society; perhaps, as suggested by the concept of 'taboo', when controlling certain kinds of behaviour was no longer regarded as necessary for influencing nature or nature's gods, the social control - in the form of conceptions of 'morality' - endured. Whether or not this is the case, the main point remains that until very recently in human history 'knowledge how' has been far in advance of 'knowledge what', and the effort to provide the latter has until very recently rested chiefly on imagination, fancy, fear, and wishful thinking. As suggested by reference to Thales above, the story of humankind's efforts to 'know what' in addition to 'how', but without relying on imagination and traditional beliefs, first comes fully into view with the philosophers of Greek classical antiquity from the sixth century bce onwards. Thales, who flourished around 585 bce in Ionia on the east coast of the Aegean, is often cited as 'the first philosopher', because he is the first person known to have asked and answered a question about the nature and source of reality without recourse to myth. In desiring a more intellectually plausible account than was offered by mythographers and poets, he sought to identify the cosmos's arche ('principle'), defined by Aristotle as 'that of which all existing things are composed . the element and principle of the things that are', by working it out from what he saw around him.

His choice of candidate for the arche was: water . His thinking can be reconstructed as follows. Water is everywhere, and it is essential. It is in the sea, it falls from the sky, it runs in your veins, plants contain it, all living things die without it. Water can even be said to produce earth itself; look at the vast quantities of soil disgorged by the Nile in its annual floods. And as the clincher: water is the only substance Thales knew that can occupy all three material states of solid (when frozen), liquid (the basic state), and gas (when boiling away as steam). So, it is ubiquitous, essential, productive, and metamorphic; it is the only thing he knew to be so; it must therefore be the substance from which all other things come and on which they depend: the arche of the universe.