For although I am of such a nature that as long as I understand anything very clearly and distinctly, I am naturally impelled to believe it to be true, yet because I am also of such a nature that I cannot have my mind constantly fixed on the same object in order to perceive it clearly, and as I often recollect having formed a past judgement without at the same time properly recollecting the reasons that led me to make it, it may happen meanwhile that other reasons present themselves to me, which would easily cause me to change my opinion [. . .] But […] although I no longer pay attention to the reasons for which I judged this to be true, provided that I recollect having clearly and distinctly perceived it no contrary reason can be brought forward which could ever cause me to doubt of its truth.

– Descartes, Meditation V, Meditations on First Philosophy

The above text is a slightly edited version of the original passage. In the places I elided over, Descartes interposes God to function as the guarantor of our knowledge. Without this religious content, the passage no longer makes the epistemological point Descartes intended, but I think it can offer an interesting practical insight about discipline and decision-making. Indeed, when I first read this part of Meditations I was immediately drawn to this more mundane side of it.

In many cases, the moment we make a decision is not the moment when we enact it. The decision might be arrived at following a long process of deliberation, during which the various relevant factors are considered and weighed. We make a concerted effort to see the situation thoughtfully and rationally until we finally feel we’ve managed to perceive it clearly and distinctly. In a sober, confident state, we form a resolution and wait for the time to act on it. When that time does come, however, the matter may no longer look so settled. As a famous general once said, no plan ever survives contact with the enemy. When we’re confronted with the reality of doing, all the questions we had dealt with before open up again. Our attention is diverted from our prior conclusions, we lose sight of the reasons we saw so clearly before, and we’re seduced by countervailing concerns and alternatives.

It’s tempting, in moments like these, either to go back on the earlier decision or to re-engage in the whole decision-making process. This is problematic both because it’s exhausting and time-consuming and because, in the heat of the moment, we’re apt to exercise worse judgement. The beauty of Descartes’ trick is that it allows this process to be short-circuited. Instead of re-opening the internal dialogue about pros and cons, we can simply focus on conjuring up the emotional-intellectual state of well-founded conviction. It’s enough to recollect our earlier frame of mind, all the while remembering that it was based on clear and distinct reasoning. In other words, we can arrive at the same endpoint we were at before without having to rehearse the logical process got us there.

This tactic – it could be considered a kind of inverse affective forecasting – is only really effective when the initial decision-making process was thorough and sound. I find that only if I really did the intellectual work the first time around did I experience a level of confidence strong enough to be reconjured. And only if the feeling of confidence can be viscerally recollected is it useful in this way. When these conditions are present, though, it can be very effective.