restricted access Capacity, Mental Mechanisms, and Unwise Decisions

Capacity, Mental Mechanisms, and Unwise Decisions

judgement, guidance, information, practice

The notion of capacity implicit in the Mental Capacity Act is subject to a tension between two claims. On the one hand, capacity is assessed relative to a particular decision. It is the capacity to make one kind of judgement, specifically, rather than another. So one can have capacity in one area and not have it in another. On the other hand, capacity is supposed to be independent of the ‘wisdom’ or otherwise of the decision made. (‘A person is not to be treated as unable to make a decision merely because he makes an unwise decision.’ Department of Constitutional Affairs 2005, section 1). One may have capacity even if the decision one arrives at is seen as unwise by one’s doctor. In this short note, I explore this tension.


Capacity as the Status of a Process

Distinguishing between a lack of capacity and the making of unwise decisions helps to escape the threat of medical paternalism. One can imagine a worry like this. Decision-making capacity is assessed by the medical profession. Thus, if a subject differs in her decisions from those thought best by her doctors, she is likely to be deemed, by that very fact, to lack the capacity to make that decision. Thus, patient autonomy is undermined. One is likely only to be granted the status of having decision-making capacity if the values expressed by one’s choices accord with those of the medical profession. And hence the possibility of autonomous divergence is undermined.

That worry can be addressed by distinguishing between a lack of capacity and making merely an unwise decision. That in turn suggests a notion of capacity that is distinguished from its outputs. Thus, if capacity is not to collapse into the wisdom of the decision made, it is hard to see how else it can be construed except as a matter of using the right decision-making process. If it is not a matter of correct outputs, it must instead be the correct process. [End Page 127]

But this suggests a problem. How, independently of the actual outcomes of the process, is the process itself to be, first, characterized and, second, assessed? This is not to say that the outcomes need have no epistemic role. They may serve as evidence for (the identification of) the process. Still, if a decision-making process (rather than the wisdom of the outcome) is to underpin the status of capacity, there had better be a way to characterize it that is independent of each output decision.

In the next section, I outline the characterization of process implicit in the Mental Capacity Act. I suggest that it may seem to motivate, or justify, or presuppose the idea that a mental process (underpinning capacity) is itself realized, or processed, by a mental mechanism. If the process is the process of a mechanism, then it makes sense to say that the process can be independent of its output choices. But, as I argue in the section after that, there are arguments drawn from Wittgenstein to criticize the very idea of a mental mechanism. Thus, there is reason to question the principled distinction between process and output.

The Process as Suggested by the Act



  1. a. to understand the information relevant to the decision,

  2. b. to retain that information,

  3. c. to use or weigh that information as part of the process of making the decision, or

  4. d. to communicate his decision (whether by talking, using sign language or any other means). (Department of Constitutional Affairs 2005, section 3)

Not all of these, however, seem equally useful in...