Here is an argument for philosophy as a way of life:
P1 Reason should be the dominant capacity for directing one’s life
P2 Philosophy is the perfection of reason
Conclusion: Therefore philosophy is the best way of directing one’s life
The controversial premise is P2. This idea of the perfection of reason is one way of capturing what ancient philosophers thought they were doing. Plato, Aristotle, and the Hellenistic philosophers who followed them judged human activity in light of its relationship to a cosmological order. For Plato, the form of the good supplied the organizing principle for reality. Aristotle’s more naturalistic view was that each kind of thing had a final end towards which it was striving; for human beings that was eudaimonia, roughly translated as “flourishing.” In any case, both agreed that this cosmological order, in which human values were embedded in its structure, was something to which human lives must conform if they were to be good lives. It was philosophical reasoning oriented toward discovering the truth that enabled us to discover that organizing principle and how we might get our actions to conform to it. Thus, the perfection of human life required the perfection of our capacity to reason which was philosophy’s job to hone.
Modern philosophers following Kant have given up this idea of a cosmological hierarchy of supreme values to which our lives must conform. The focus shifts to the actions of individuals and whether they conform to rational moral principles. The shape of one’s life is up to the individual. It is no longer a primary philosophical concern as long as one stays within the boundaries of the rules that govern social life. Philosophy is no longer concerned with the details of how one lives. It’s focused on justifying universal principles of good conduct, demonstrating why lying is wrong, or why societies must be organized around a particular conception of justice. Philosophical reflection on morality has become an exercise in formulating abstract, general rules that are not woven into the fabric of everyday life. A sense of justice or a disposition to tell the truth can be had by non-philosophers who recognize from within the activities of their own lives that things go well when they adhere to moral norms. A decent person needs no such philosophy and philosophical reasons have no power to encourage decency.
Thus, to whatever degree philosophy is the perfection of reason, it has little to do with the kind of reasoning people use to get through the day. The notion of reason in P1, a genuinely practical reasoning about how to negotiate the particular circumstances of one’s life, has little to do with the notion of reason in P2 which refers to the kind of abstract very general reasons one might employ if they were constructing society rather than living in it.
If the argument for philosophy as a way of life is to work, it must revise its concept of reason to track the particularities of individual lives but without the metaphysical foundations of the ancients.