In Letter 31, the 4th C. Archbishop of Constantinople Gregory Nazianzen writes,
On the contrary, you must do philosophy in your suffering. Now more than ever, this is the moment to purify your thoughts, and to reveal yourself as superior to your bonds [which tie you to your body]. You must consider your illness a pedagogue which leads you to what is profitable to you–that is, teaches you to despise the body and corporeal things and all that flows away, is a source of worries, and is perishable, so that you may belong completely to the part which is above,… making this life down below–as Plato says–a training for death, and liberating your soul in this way, as far as possible, both from the body [soma] and from the tomb [sema], to use Plato’s terms. If you philosophize in this way,… you will teach many people to philosophize in their suffering.
It would be a mistake to label Gregory’s spiritual exercise a “thought experiment.” But why? Because a thought experiment runs in one of two directions, either testing our basic intuitions or affording us an opportunity to consider what is logically (or imaginatively) conceivable. Robert Nozick’s famous thought experiment, the Experience Machine, asks us to consider what it’s like to be in an unending state of complete pleasure and whether we would opt for that. But in neither way does a thought experiment demand anything weighty of us: it doesn’t make us answerable for our lives. It leaves us, as it were, right where it found us.
A spiritual exercise, by contrast, demands much more of us. It enjoins us to live a certain way: the way of the righteous and purified, for Gregory; the way of the virtuous for the Stoics. It is not enough for us to assent to a certain line of thought, though this may be required of us. Nor is it enough to feel a certain way, though feel we must. To undertake a spiritual exercise is to re-habituate ourselves to the world not once or twice, not when the mood should strike us, but over and over again. It is as if spiritual exercise were to cast upon us an entirely new outlook, a reorientation to all that is.
During spiritual exercise, our whole being–our thinking, our feeling, our very breath–is called upon to follow a particular way of life. We must be careful, though, to remain always in the spirit of rational inquiry so that we’ll have the strength to resist zealotry. Should we elect to become a Stoic or an Aristotelian or, to coin a term, a Montaignean, we can’t give up on submitting, at least in principle, everything we do and say to ruthless examination. How could we?
The key is to be zealous (that is, to be devoted to the practice of self-examination) without becoming a zealot. And what safeguards philosophy from zealotry? None other than its search for wisdom. But how exactly? By being so elusive. That is, by regarding the search for wisdom as an activity, an activity of judging that this is so, that this is right, that this is where we stand. And? And by keeping us honest, requiring us to modify our judgments in light of errors, anomalies, and confusions. And? And finally by reminding us of our flaws–through laughter, beautiful and beatific.