The struggle over how we, as frail and vulnerable human beings, can use reason to make our way in the world, and work towards and preserve the good for us and for others, is explored by Martha Nussbaum in her book entitled The Fragility of Goodness (2001). By setting out the arguments of the Greek philosophers as they wrestle with the question of how human beings can make a more certain world and inure themselves against the vagaries of chance, Nussbaum navigates the paradox of the knowable and the unknowable, the precise and universal versus the particular and messy:
We have reason. We are able to deliberate and choose, to make a plan in which ends are ranked, to decide actively what is to have value and how much. All this must count for something. If it is true that a lot about us is messy, needy, uncontrollable, rooted in the dirt and standing helplessly in the rain, it is also true that there is something about us that is pure and purely active, something that we could think of as “divine, immortal, intelligible, unitary, indissoluble, ever self-consistent and invariable”. It seems possible that this rational element in us can rule and guide the rest, thereby saving the whole person from living at the mercy of luck.
In the book Nussbaum contrasts the philosophy of Plato, who struggles to gain an unconditional vantage point of the good beyond the cave of appearances, with that of Aristotle who urges a return to these appearances as a way of rediscovering our humanity. For the former, science, or techné, holds out the prospect of allowing us to weigh, count and measure as a means of achieving endless progress and refinement towards the ideal. If we could reduce things which are different in kind to being commensurable, and thus capable of being quantitatively evaluated, then it would reduce uncertainty about what is to count as a good activity, since we can produce universally applicable measures where we can judge one quantity of a thing against another. We are merely presented with the choice of more or less of the same thing. Techné holds out the prospect of liberating us from our ordinary intuitions and attachments, which are unreliable and hold us hostage to our fallible humanity and to fate.
For Aristotle, according to Nussbaum, the striving towards a universal vantage point seems to deny the very conditions that make us human, since they try to pass over and deny the importance of the day to day complex phenomena in which our lives consist. If for Plato the only thing that makes life worthwhile are activities which take us away from the cave and up into the sunlight, for Aristotle it is the here and now, the diurnal messiness, towards which we should turn our attention:
But if it is a universal human desire to grasp the world and make it comprehensible to reason, then it seems clear that oversimplification and reduction will be deep and ever present dangers. In seeking to be at home, we may easily become strangers to our own home as we experience it. In our anxiety to control and grasp the uncontrolled through techné, we may all too easily become distant from the lives we originally wished to control…We need philosophy to show us a way back to the ordinary and to make it an object if interest and pleasure, rather than contempt and evasion. (2001: 260)
Aristotle criticises Plato for adopting a ‘god’s eye’ view of ethical action, forming universal judgements about the good outside of any particular human frame of reference. He himself is more interested in the plurality of the good, which can only be assessed, he would argue on the basis of judgement derived from experience. The difficulty of deriving universal rules and trying to apply them in advance of the experience itself is that it closes off the possibility of surprise. For Aristotle, in cases of judging the good, rules are just rules of thumb, with each particular circumstance that we encounter capable of providing substance for the revising of these rules. By focusing on the practical, Aristotle notices that everyday experience is by its very nature changeable and complex, thus much less amenable to precision and universality.
Plato aspires to an ideal world of abstract universals, where detached rationality acts as a hedge against the fragility of human goodness. Aristotle advises us that giving priority to the general over the particular loses us the ethical value of surprise, contextuality and particularity, which makes us more vulnerable, but is at the same time an acknowledgement of our humanity.
 Euripides – Trojan Women.