Moral psychology, empirical work in

4. Weakness and strength of will

We all sometimes succumb to temptation, exhibiting a kind of moral weakness when the action has moral significance (e.g. adultery). Some of us are characteristically weak-willed, while others are typically strong-willed, and each individual’s willpower fluctuates depending on the circumstances (e.g. when intoxicated). Interesting philosophical puzzles arise with such phenomena, but some have been concerned with a precise characterization of them in the first place, or whether they even exist at all. Some have defined ‘weakness of will’ as akrasia – i.e. acting, or having a disposition to act, against one’s judgment about what is best (see Akrasia). Others have focused on action that is contrary to what one intends to do (see Holton 2009: ch. 4). But there is some empirical evidence that neither of these exhausts the ordinary notion of being weak-willed; both factors seem to play some role, while evaluative considerations do as well (see May and Holton 2012).

However we construe weakness, its opposite – strength of will – also deserves attention (see Self-control). Focusing on intentions, we can inquire into what mental states and mechanisms underlie our ability to stick to what we’ve planned to do. Consider the phenomenon of ‘ego depletion’, in which self-control resources are used up over time. Social psychologists, especially Roy Baumeister and colleagues (Muraven et al. 1998) have discovered that we are less likely to persist in activities that require self-regulation if we have recently already done so. For example, people cannot hold a handgrip exerciser for as long if they recently had to suppress emotional reactions while watching a sad movie clip. Strength of will, it seems, works like a muscle in that it can be strengthened, weakened, and has a limited store of energy on which to draw.

Importantly, the effects of ego depletion can occur across a variety of domains, such as dieting and solving puzzles. A neo-Humean account would attempt to explain this only in terms of beliefs and desires. But such explanations might have difficulty accounting for the global effects of ego depletion. Why, for example, would a desire to avoid eating some tempting food item affect one’s desire to persist in holding a handgrip exerciser? Those parting with the Humean tradition may posit intentions as a distinct mental state, not reducible to beliefs and desires (see Intention §2). But one might go even further and posit a faculty of willpower that is distinct from these various states of mind (Holton 2009: ch. 6). This appears to have the advantage of explaining the systematic effects of ego depletion.

Examining such research, one might conclude that an even more general phenomenon is occurring here. A scientifically fruitful categorization of cognitive processes divides them into two basic kinds, yielding a ‘dual-processing’ approach. System 1 processes are quick, automatic, relatively independent of conscious control, and so on. System 2 processes are slow, effortful, guided by consciousness, etc. Weakness of will, then, may be encompassed in the more general category of actions that are predominantly the result of System 1 resources when those from System 2 have been recently exhausted (Levy 2011). This would nicely model the phenomenology of weakness: sticking to the plan of doing what’s best is effortful and often giving in feels like letting a passion take over. Tying the more ordinary phenomena of weakness and strength of will to categories in cognitive science in this way may help illuminate the philosophically interesting issues surrounding them (see Sripada 2010).