   Several significant developments occurred in the ways Greeks thought and spoke about the soul in the sixth and fifth centuries. The questions about the soul that are formulated and discussed in the writings of Plato and Aristotle to some extent arise from, and need to be interpreted against the background of, these sixth and fifth century developments.  One factor that is of central importance is the gradual loss of the Homeric connection between mentioning a person's soul and the thought that their life is vulnerable or at risk (contra Burnet 1916, 253). In ordinary fifth century Greek, having soul is simply being alive; hence the emergence, at about this time, of the adjective ‘ensouled’ [empsuchos] as the standard word meaning “alive”, which was applied not just to human beings, but to other living things as well.  There is some reason to think that the word ‘soul’ was used in this straightforwardly positive way already in the sixth century. Thales of Miletus, who is credited with successfully predicting a solar eclipse occurring in 585, reportedly attributed soul to magnets, on the grounds that magnets are capable of moving iron (Aristotle, De Anima 1.2, 405a19-21). Thales' thought was presumably that since it is distinctive of living things to be able to initiate movement, magnets must in fact be alive or, in other words, ensouled. Thus, while Homer spoke of soul only in the case of human beings, in sixth and fifth century usage soul is attributed to every kind of living thing. What is in place, then, at this time is the notion that soul is what distinguishes that which is alive from that which is not. 