In contrast to Plato, Aristotle allowed and argued for the possibility that all human lives have some non-instrumental value. This valuation of life is premised on his teleological conception of nature: insofar as all human lives are natural ends of some sort, they are thus a good. However, this non-instrumental value of mere living is in itself not sufficient to make a life worth living. As in Plato, whether a life is lived well or badly is the decisive factor, and again the state of virtue or vice is the most important consideration. Vice makes a life worse than death, regardless of the other good things in it, but fully fledged virtue is not necessary for a life worth living. In contrast to those who are fully virtuous, other non-vicious humans may need other goods, or at least freedom from other bads, such as serious illness or grave misfortunes, to pass the threshold of a life worth living. In contrast to Plato, Aristotle is less optimistic about the chances of the non-educated elite having a life worth living, though he does not flatly deny that possibility.