The law adopts a cliff-edge approach to capacity, drawing a bright line between those who are deemed to have the capacity to make a decision and those who are not. This reflects Enlightenment ideas about the limits of legitimate state authority, according to which substantial justification is required before the state can interfere with the autonomous choices of its citizens. Given its role in distinguishing those who are capable of making autonomous choices (to whom the state defers) from those who are not, it is generally assumed that the test for capacity must be neutral as to the substance of the values, beliefs, or reasons underpinning any given decision, so as to leave proper space for individual autonomy. As a result, the Mental Capacity Act 2005 adopts a process-orientated account of capacity, which focuses on whether certain of the person’s cognitive capacities are intact, and not on the outcome of the decision, or on the substance or origins of values or beliefs which underpin it.

This chapter considers how the law might be reformed so as to better capture circumstances in which an agent’s capacity for autonomous decision-making is being undermined by a disorder or impairment which affects the values or beliefs that the agent applies to the information. It will begin by exploring the merits of including an ‘appreciation’ criterion in the test for capacity, before going on to consider whether more other, more explicit, criteria would be preferable. It will conclude that the challenges inherent in devising a workable legal test lean in favour of the law adopting a more blunt approach which focuses on the origins of the values or beliefs that the agent applies to the information in their decision-making. A new limb of the MCA is therefore proposed, which asks whether the person is unable to make a decision because the values or beliefs by which they evaluate the relevant information have been caused by or altered as a consequence of the person suffering from a disorder, illness, or impairment. Various potential challenges to such a provision will be explored and responded too.

This chapter will explore a key problem with the current law’s approach – namely, that it is impossible to assess a person’s capacity to ‘use or weigh’ the information relevant to a decision without engaging with the values that underpin their decision. It will suggest that while some recourse to the person’s values is unavoidable, the current approach gives assessors ample room to invoke other values when assessing the person’s capacity, thus creating space for paternalistic judgments to go unchecked. Despite this risk, it will be claimed that in many of the cases in which this occurs, underpinning the assessment is in fact a concern that the values or beliefs that motivate a person’s decision have been affected by an illness or impairment, such that the decision reached is not one that the agent would have made, but for that disorder or impairment. The current law cannot account for this, and so assessors are forced to manipulate the test for capacity instead. While this prevents unnecessary harm, it has the effect of obscuring the value-laden and highly controversial claims that may underpin such decisions, which remain insulated from scrutiny or challenge.