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Herring, Jonathan --- "Peter Skegg and the question no-one asks: why presume capacity?" [2016] OtaLawFS 23; Law, ethics, and medicine: essays in honour of Peter Skegg 32

Last Updated: 31 May 2019



Jonathan Herring*


Practising lawyers rarely address issues of hard law. Much of their work is a mixture of counselling, negotiation and threats. Good academic lawyers prefer to address the complex questions of law that rarely arise, but which do not have an easy answer. Brilliant academic lawyers dig deeper and challenge the assumptions that underpin the law. And speaking of brilliant academic lawyers, there is no doubt Peter Skegg falls into that category. He is deservedly acknowledged as one of the foremost pioneers of medical law. In an astonishing career he has left a remarkable legacy. There can be few academics working in medical law who do not (consciously or unconsciously) owe him a considerable academic debt.

In this chapter I want to consider one example of his brilliance. It is an article which raises a foundational principle and subjects it to a sophisticated critique.1 It asks: ‘why in the medical context should we presume people have capacity?’ That question is rarely asked because it is taken for granted. The presumption of capacity appears prominently in the textbooks, with little attempt to justify or explain its existence.2 Berghmans, Dickenson and Ter Meulen note that although there is much dispute over the notion of mental capacity, there is ‘consensus’ that there is and should be a presumption in favour of capacity.3 In his detailed analysis Peter Skegg demonstrates that if there is such a consensus it deserves far more consideration than it typically receives.

In this chapter I will summarise Peter’s arguments and (as I am sure he hopes his readers will) reflect further on why it is we assume people have capacity and whether we should. I will, in fact, end up being even more sceptical about the presumption than he was.

* Exeter College, University of Oxford.
1 PDG Skegg “Presuming Competence to Consent: Could Anything be Sillier?” (2011) 30

UQLJ 165.

  1. See, for example, (embarrassingly) J Herring Medical Law and Ethics (5th ed, Oxford University
    Press, Oxford, 2014) at 154.
  2. R Berghmans, D Dickenson, and R Ter Meulen “Mental Capacity: In Search of Alternative
    Perspectives” (2004) 12 Health Care Analysis 251.


The presumption of capacity is commonly put in terms such as these (taken from the English and Welsh Mental Capacity Act 2005):4

A person must be assumed to have capacity unless it is established that he lacks capacity.

Peter Skegg’s analysis shows that this simple proposition is highly ambiguous. He highlights three uncertainties.

First, it is unclear whether the presumption only applies to legal proceedings, requiring that a person seeking judicial intervention on the basis that a patient lacks capacity must prove the person does indeed lack capacity. Or does it have a role in the clinical context, demanding that a medical professional must presume a patient has capacity? As he notes these are very different propositions, yet the straightforward presentation of the presumption does not tell us which version of the presumption is correct or indeed if both are.

Second, Peter Skegg demonstrates that there is uncertainty over the strength of the presumption. In other words, how strong the evidence must be if the presumption is to be rebutted. In the statutory formulation the presumption appears to be a general one of equal application. But, in a rigorous analysis of the case law he highlights the comments of Lord Donaldson in Re T:5

What matters is that doctors should consider whether at the time [the patient] had a capacity which was commensurate with the gravity of the decisions which he purported to take. The more serious the decisions, the greater the capacity required.

What matters is whether at that time (i.e. at the time of the refusal) the patient’s capacity was reduced below the level needed in the case of a refusal of that importance, for refusals can vary in importance. Some may involve a risk of life or irreparable damage to health. Others may not.

This suggests that the strength of the presumption (in so far as it exists) may vary depending on the gravity of the issue at hand: the more harmful the effect of the decision the weaker the presumption and indeed more is needed to establish capacity. A medical professional faced with a patient refusing life-saving treatment whose decision will lead to their death or serious disability will want to be sure this is the patient’s capacitous decision before relying on it. In such a case it may seem

4 Mental Capacity Act 2005, s 1(2).
5 Re T (Adult: Refusal of Treatment) [1992] EWCA Civ 18; [1993] Fam 95 at 112, 115.

more accurate to talk about a presumption of incapacity. No doctor would want to let a patient die on the basis that they might possibly have been capacitously refusing to consent to the treatment. By contrast, less persuasion will be required as to the competence of a patient refusing to consent to take an aspirin for a headache. Although, as Skegg astutely notes, the difference between grave and non-grave decisions is not as straightforward as “the importance of a decision may be assessed by different people in different ways”.6 Skegg’s point about capacity depending on the severity of the issue could also be supported by the general shift towards “an issue based approach” to capacity: the assessment is of an individual’s ability to make a particular decision, rather than their general capacity to make decisions. Hence, a patient (P) may lack capacity to make one decision, but have capacity to make a different decision.7 P may be able to consent to eat chocolate ice cream, but not to consent to sign a will. Whether P has capacity can depend on the complexity of the issue.

Third, even if the presumption does apply, there is uncertainty over how it is to be used in practice. In relation to the clinical issue, Peter Skegg quotes Lord Donaldson: “Doctors faced with a refusal of consent have to give very careful and detailed consideration to the patient’s capacity to decide at the time when the decision was made”.8 As this quote indicates, a doctor cannot rely on the presumption as an excuse for not carrying out an assessment of the patient’s capacity. For English and Welsh lawyers The Mental Capacity Act Code of Practice states that “... it is important to carry out an assessment when a person’s capacity is in doubt”.9 To fail to carry out a proper assessment of capacity could well be negligent.10 It is true that the sophistication of the assessment may vary from patient to patient and the severity of the issue. But it is hard to imagine it is ever appropriate to rely solely on the legal presumption of capacity and not to make some form of assessment, however basic.

But if an assessment is always required, what role is left for the presumption of capacity? It seems the presumption is restricted to cases where an assessment has been made, but the result is inconclusive. Indeed, even there its relevance may be

6 Skegg, above n 1, at 168.
7 See, for further discussion, J Herring and J Wall “Capacity to Cohabit: Hoping ‘Everything

Turns Out Well in the End’ PC v City of York [2013] EWCA Civ 478” (2013) 25 Child and Family Law Quarterly 471.
8 Re T (Adult: Refusal of Treatment) [1992] EWCA Civ 18; [1993] Fam 95 at 113A.
9 Department for Constitutional Affairs Mental Capacity Act Code of Practice (The Stationery

Office, London, 2007) at [4.34].

10 J Coggon and J Miola “Autonomy, Liberty and Medical Decision Making” (2011) 70 CLJ 523.

questioned. Case law has reinforced the point that if there are uncertainties about a patient’s capacity then the case should be brought to court. For example, in Re B it was held that if after the assessment there remained “a serious doubt about the patient’s competence” then “the seriousness or complexity of the issues in the particular case may require the involvement of the court”.11 Similarly, in all the debates over assisted dying, even strong supporters accept that a person seeking assistance in death should be assessed for capacity.12 So, it seems the presumption is of very limited application. Perhaps at most it is limited to cases concerning minor matters where the doctor has made an inconclusive assessment of capacity. As Peter Skegg’s analysis of the case law concludes:13

Despite the frequent references to the presumption of capacity in medical law texts and elsewhere, there do not appear to have been any English medical law cases in which the common law presumption of capacity led to patients being regarded as competent when, but for that presumption, they would have been regarded as incompetent.

This conclusion I would wholeheartedly agree with. In this chapter I want to take up the baton and explore further the question why it may be that the law claims to presume capacity and whether it should.


Before exploring the issue further, it is helpful to consider the nature of a presumption. Straightforwardly, a presumption is a legal device of reasoning that allows a decision maker to reason from situation A that a particular conclusion, B, should be reached, unless there is evidence to show B is untrue.14 These are commonly used in law, perhaps the best known being the presumption of innocence, meaning it is presumed a defendant charged with a criminal offence is innocent, unless there is sufficient evidence to show he or she is guilty. Legal presumptions can be of varying strengths. Some presumptions are “edifices of extraordinary strength and durability which would take a powerful array of

11 Re B (Adult: Refusal of Medical Treatment) [2002] EWHC 429; [2002] 2 All ER 449.

12 A Price and others “Concepts of Mental Capacity for Patients Requesting Assisted Suicide: A Qualitative Analysis of Expert Evidence Presented to the Commission on Assisted Dying” (2014) 15 BMC Medical Ethics 32.
13 Skegg, above n 1, at 177.

14 M Skivenes “Judging the Child’s Best Interests: Rational Reasoning or Subjective Presumptions?” (2010) 53 Acta Sociologica 339.

arguments to overcome”;15 while others are “lightly held”,16 being rebuttable by any evidence to the contrary.17

Why does the law rely on presumptions? There are two main reasons: presumptions based on statistical observation and presumptions based on principle. Statistical presumptions are used to claim that as a matter of common sense, or statistics, a fact can be established by proving a different fact. If there is a strong statistical correlation between A being true and B being true then the court is entitled to assume in a case where A is shown to be true that B is true, unless there is good evidence it is not. For example, we might assume that it would be dark in an unlit area at 11pm. In a case considering an incident at 11pm on a particular evening it would not be worth the time of the court establishing it was dark, given that statistically, it nearly always is dark at 11pm. It would simply be a waste of court resources to prove the darkness, unless there was reason to think that day was different from the norm.

For the issue at hand, the statistical argument would be that nearly always adults have capacity. In other words, that a member of the public selected at random would be competent and this should be taken into account when determining whether a particular person has capacity. Just as we might assume that a person selected at random was sighted, unless there was evidence to suggest otherwise. We do not normally require in a court case proof a person can see, unless there is evidence to suggest otherwise.

However, presumptions are not always based on statistics, they may be based on a legal principle. Peter Skegg quotes John Salmond on this issue:18

Many ... presumptions are based on no real estimate of probabilities, but are established for the purpose of placing the burden of proof upon the party who is best able to bear it, or who may most justly be made to bear it. Persons accused of crime are probably guilty, but the presumption of their innocence is in most cases and with certain limitations clearly expedient.

15 JH Wilkinson III “Toward a Jurisprudence of Presumptions” NYUL Rev 67(5) (1992) 907 at 907.
16 At 907.

17 An example in English law would be the rebuttable presumption of no consent found in the Sexual Offences Act 2003, s 75.

18 JW Salmond Jurisprudence or The Theory of the Law (Stevens and Haynes, London, 1902) at 590.

Take the example of the presumption of innocence mentioned by Salmond. There can be lively debates over what percentage of people charged with a criminal offence are in fact innocent. Let us assume, as seems likely, the percentage is not so high as to make the presumption of innocence justifiable as a matter of statistics. Rather it is a presumption based on a principle. A conclusion that the outcome of the law (the guilt of the accused) is such a serious outcome, liable to cause the defendant such harm, that we should only do this if we are certain or as certain as we can be about the guilt. This is not based on the implausibility of the accused being innocent, but the severity of the interference of his or her rights if they are found guilty.

Note that the reason behind the presumption may well determine its strength. In the case of statistical presumptions, the presumption will be a weak one. The court would rather rely on what is proved about this particular person, rather than what is generally true about people. Relying on generalisations seems a last resort, particularly if evidence is available about the actual issue at hand. The danger of moving from an assessment of what is commonly true to what is true for a particular case was recognised by the English Supreme Court in Re B (a Child).19 There the Supreme Court, looking at the welfare of a child, held that something being generally true for children does not help the court determine what is true for a particular child. That was particularly because the cases that come before the courts are not normal.

On the other hand, the presumption based on an important legal principle seems a strong one. The importance of not convicting the innocent is a principle which is generally true. We do not have the difficulty of moving from the general to the specific that we do with statistical presumptions. The presumption is being used here to protect basic human rights. A strong justification will always be required to do that. We could say the same about the presumption of capacity. To give someone medical treatment without their consent will always infringe their human rights and therefore always requires a strong justification.

With these points in mind, let us consider whether the presumption in favour of capacity can be justified in terms of either a statistical presumption or a presumption of principle.

19 Re B (a Child) [2009] UKSC 5.


Can the presumption of capacity be justified on the basis that it is statistically the norm? If 95% of patients have capacity, then it seems unobjectionable for a doctor or even a court to assume a patient has capacity, unless there is evidence to the contrary. However, it will be argued that the suggestion that anything like 95% of people have capacity to make medical decision is highly questionable. As Welie and Welie suggest:20

The autonomous patient – or, more precisely, the patient who invokes his right to respect his autonomy in order to exert his freedom and personal responsibility – is the exception rather than the rule. The incompetent patient is the rule, the starting point – or, more precisely, the patient in the care of whom concerns about autonomy (in the libertarian sense of that term) do not even arise ... The question, then, is not when does a patient become incompetent, but what makes him competent such that his call for respect of his autonomy must be granted, notwithstanding risk to well-being, health or life.

That is a surprising claim but one which is not, I suggest, ill-founded in the medical context.

The standard model of capacity is that P must understand the relevant information and be able to use the information to make a decision. As section 3 of the Mental Capacity Act 2005 puts it:

... a person is unable to make a decision for himself if he is unable

(a) to understand the information relevant to the decision,
(a) to retain that information,
(a) to use or weigh that information as part of the process of making the decision, or
(a) to communicate his decision (whether by talking, using sign language or any other means).

Let us explore these elements a little further and see if the claim that a large majority of the population are in a position to claim capacity can be substantiated.

20 J Welie and S Welie “Is Incompetence the Exception or the Rule?” (2001) 4 Medicine, Health Care and Philosophy 125 at 125.

3.1 Information

To have capacity a person (P) must understand the key facts relevant to the decision. P cannot be taken to have made a decision unless she understands her current position, the treatment that is being offered, and the potential consequences of the treatment. It seems unlikely that we could presume that a patient will know the information concerned. At least that will not be true for more complex procedures. Doctors’ training is lengthy and complex precisely for that reason.

Consider, for example, the question of consent to delivery of a baby. Cobb J recently held:21

In considering the mode of the delivery of the baby, I suggest that a prospective mother would need to be able to understand, retain and weigh the information relevant to:

(i) Ante-natal care and monitoring, including blood tests to check for anaemia and diabetes; urine tests to check for infections; the benefits of discussion with health services about delivery options;
(i) Ante-natal monitoring of the foetus; the value of an ultra-sound imaging;
(i) Mode of delivery of the baby, including vaginal delivery, and caesarean section;
(i) Natural and/or induced labour;
(i) Anaesthesia and pain relief;
(ii) The place of delivery – e.g. at home or in a hospital – and the risks and benefits of each option;
(ii) The risk of complications arising from conditions relevant to the mother or the baby;
(i) Post-natal care of mother and baby.

It is hard to believe that a very high percentage of the population could be taken to know this information.

3.2 Using Information: Rationality

To be autonomous a person must not only understand the information, they must be able to use it. Jennifer Drobac and Oliver Goodenough, in their analysis of the

21 The Mental Health Trust v DD [2014] EWCOP 11 at [65].

psychology of decision-making, list the following requirements for rational use of information:22

(i) parties with stable, well ordered preferences;
(ii) choices that are fully voluntary and unconstrained;
(ii) relatively equal, and ideally complete, information;
(ii) relatively equal bargaining power and experience;
(ii) sufficient cognitive capacity to evaluate the transaction and to exercise voluntary control over the conflicting factors and emotions involved;
(ii) the absence of monopoly power or other distortions of the market;
(ii) the presence of good faith and absence of fraud in both parties; and
(ii) a level of consequence for a mistake that is not disastrous to the party.

The authors, after examining the latest neuroscience and psychology studies, suggest that few people have capacity.23 They are not alone in their analysis. Neil Levy refers to a wide range of psychological studies that reveal “fallibilities of human reasoning” (including “myopia for the future”, “motivated reasoning”24 and “biases” in “assessing probabilities ... exacerbated ... under cognitive load”).25 He concludes that:26

Human beings are, under a variety of conditions, systematically bad reasoners, and many of their reasoning faults can be expected to affect the kind of judgements that they make when they are called upon to give informed consent.

To similar effect Sarah Conly writes:27

As has by now been discussed convincingly and exhaustively (notably by Nobel Prize-winning Daniel Kahneman and Amos Tversky), we suffer from common, apparently ineradicable tendencies to ‘cognitive bias,’ which means that in many common situations, our decision-making goes askew. These biases are many and varied, but they have in

22 J Drobac and O Goodenough “Exposing the Myth of Consent” (2015) 12 Indiana Health Law Review 471 at 496.
23 At 498.

24 N Levy “Forced to be Free? Increasing Patient Autonomy by Constraining it” (2012) 40 J Med Ethics 293 at 295.
25 At 297.
26 At 295.
27 S Conly “Against Autonomy: Justifying Paternalism” (2014) 40 J Med Ethics 349.

common that they interfere with our appreciation of even quite simple facts, and lead us to choose ineffective means to our ends.

In Peter Skegg’s article he refers to the ample evidence that many of those requesting suicide are not affected by psychiatric disorders (although, of course, by no means all).28 One study into adolescent suicide found that only 8% had been contemplating taking an overdose for at least twenty-four hours, indeed most less than fifteen minutes. In such cases, presuming these people are acting autonomously, and so not intervening or offering any medical help would not be promoting their autonomy, rather undermining it. Suicide, is of course, an extreme case. But the difficult cases involving the presumption are likely to be where someone is refusing serious treatment and often many of the similar issues arise.

3.3 Making a Decision for Themselves

Let us assume, for the moment, that contrary to what I have just argued, there is evidence that generally people do know the medical information that is needed and are able to use the information. Still more is required to have the capacity to exercise autonomy. It is necessary for a person to have values and relate the information to their goals.29

Catriona Makenzie and Wendy Rogers argue that to be able to exercise autonomy people need to be the following:30

[Being] able to determine one’s own beliefs, values, goals and wants, and to make choices regarding matters of practical import to one’s life free from undue interference. The obverse of self-determination is determination by other persons, or by external forces or constraints.

Being able to make choices and enact decisions that express, or are consistent with, one’s values, beliefs and commitments. Whereas the threats to self-determination are typically external, the threats to self-governance are typically internal, and often involve volitional

28 Skegg, above n 1, at 182.

29 See, for further discussion, J Herring and J Wall “Autonomy, Capacity and Vulnerable Adults: Filling the Gaps in the Mental Capacity Act” (2015) 35 Legal Studies 698.

30 C Mackenzie and W Rogers “Autonomy, Vulnerability and Capacity: a Philosophical Appraisal of the Mental Capacity Act” (2013) 9 International Journal of the Law in Context 37.
31 At 42.

or cognitive failings. Weakness of will and failures of self-control are common volitional failings that interfere with self-governance.”32

A person’s decisions, values, beliefs and commitments must be her ‘own’ in some relevant sense; that is, she must identify herself with them and they must cohere with her ‘practical identity’, her sense of who she is and what matters to her. Actions or decisions that a person feels were foisted on her, which do not cohere with her sense of herself, or from which she feels alienated, are not autonomous.”33

I would certainly question how many people are in a position to do all of these things, particularly in the case of patients refusing strongly recommended treatment. A good number of cases where patients are refusing treatment are those where a patient is affected by a fear or disorder where there is a question mark over the extent to which their decisions are genuinely their own. Of course, there are plenty of those refusing who do have capacity. My point is simply that we are well short of the kind of percentages that would justify a statistical presumption.

My conclusion is then that any argument that we can properly assume that the large majority of people have capacity to make autonomous decisions is unfounded. It cannot form the basis of a presumption of capacity. But, as already indicated, it may be that the presumption is not a presumption of fact based on statistics, but one that protects an important principle. I need to consider that possibility next.


It is commonly suggested that the presumption of capacity is based on the principle of respect for human rights. For example, Berghmans, Dickenson and Ter Meulen suggest the presumption expresses “respect for autonomy and dignity rights”.34 Eric Vogelstein writes:35

A competent patient has a strong prima facie right, based on the moral value of her autonomy or self-determination, to determine her own medical treatment (or lack thereof); an incompetent patient lacks that strong prima facie right.

32 At 42.
33 At 43.

34 R Berghmans, D Dickenson and R Ter Meulen “Mental Capacity: In Search of Alternative Perspectives” (2004) 12 Health Care Analysis 251 at 253.
35 E Vogelstein “Competence and Ability” (2014) 28 Bioethics 235 at 235.

The presumption of capacity on this understanding plays its role in maximising the number of people able to exercise their right to make their own decisions. As Michael Gunn puts it:36

Respect for autonomy is the guiding principle in health care law. It is, therefore, essential that a test for capacity sets a standard which allows as many people as possible to take their own treatment decisions.

The argument is, therefore, that just as the presumption of innocence is designed to support the view that we would rather the guilty go free than the innocent be acquitted, so the presumption for capacity is based on a claim that we would rather find a person without capacity to be capacitous, than treat a patient as lacking capacity who in fact has capacity.

If that is the basis for the presumption, I think it is highly questionable. Let us take two people, A and B, who consent to treatment proposed by the doctor. They are assessed by a doctor and are found to be of uncertain capacity. In fact, unknown to anyone, A does have capacity and B lacks capacity.

Let us first imagine the law applies the presumption of capacity. In that case both A and B would be presumed to have capacity and both receive the treatment.

Imagine now the law has no presumption of capacity. As capacity has not been established A and B are treated as lacking capacity. Then the best interests test applies and so they will be given the recommended treatment based on this test.

So, in cases of consent to treatment it makes no difference whether we presume capacity or not in borderline cases. Either way, the treatment can be given. The presumption cannot be said to be necessary to promoting human rights in such a case because it makes no difference.

What about cases where A and B refuse treatment? Now we do see a difference. If the presumption of capacity is applied in the law it is presumed that A and B have capacity and their refusal to consent must be respected and the treatment is not offered. If there is no presumption of capacity then A and B will not be found to have had capacity and the treatment will be given based on the best interests assessment.

However, would it be correct to say that the presumption of capacity in this case is more rights enhancing? I would question that. It will be for A. For A the presumption means their true autonomous wish to refuse is respected if the

36 M Gunn “The Meaning of Incapacity” (1994) 2 Medical Law Review 8 at 9.

presumption applies, but it is not if the presumption does not apply. But that is not true for B. If the presumption applies and B is not given the treatment recommended by the doctor this is not enhancing B’s autonomy, nor protecting B’s rights. They suffer harm as they are denied beneficial treatment. This may have serious consequences for their long term welfare and ability to exercise their autonomy in other occasions.

It is, therefore, quite wrong to suggest that the presumption of capacity can be understood as tied to the desire to promote autonomy or rights. As Peter Skegg explains in a powerful passage:37

I very much hope that I am never rushed to an emergency department, having written a ‘do not treat’ advance directive and then taken an overdose, in an attempt to kill myself. But if that were to occur, I believe my interests (or, as some would put it, ‘human rights’) would be best furthered by clinicians seeking to assess whether I was competent at the relevant times, rather than simply presuming competence. Indeed, in these particular circumstances, I very much hope that they will — in the absence of very clear evidence to the contrary — presume incompetence. I do not believe my autonomy and human rights would be infringed by such an approach: quite the reverse. They would be giving me the chance to make what, in all probability, would be a much more competent and autonomous decision.

In short, it would be more accurate to say that the presumption of capacity protects autonomy in some cases (in those involving people assessed as being of uncertain capacity but in fact having capacity who are refusing treatment). However, in other cases (those involving a consenting patient) it makes no difference in terms of autonomy whether the presumption is applied or not. And in some cases it positively works against a patient’s rights (when a patient is assessed as being of uncertain capacity, but in fact lacks capacity, but is refusing treatment).


So far, we have been looking at the most common justifications for the presumption: that it is a reasonable statistical assessment of fact or that the presumption protects a patient’s rights. Both justifications have been found wanting. Maybe, the presumption rests on other grounds. It is, in other words, somewhat of a legal fiction. It might be said the presumption is about promoting efficiency. It is certainly how doctors generally operate. If a person seeks medical advice and is

37 Skegg, above n 1, at 179.

recommended medication and they agree to take it, the doctor does not normally feel the need to make further enquires to ensure there is capacity. Unless there is something in the interaction or the history of the patient, the doctor is unlikely to question the patient further. There are more important things for a doctor to do than ensure the patient’s consent is as richly autonomous as it could be. Requiring an expert assessment will be a waste of resources and a slowing down of the procedures.

I suggest this justification for the presumption is not adequate either (although as I will explain later it is reaching towards a sounder explanation for the presumption). There is undoubtedly a place for bureaucratic presumptions and categorisations. The age limit at which alcohol can be served at a bar is a good example. Queues would be even longer if bar staff had to quiz every customer on their understanding of alcohol before serving them. Even if they had the time bar staff lack the expertise to make the necessary assessment of customers’ understanding. Simply using a rough and ready age cut off is workable for bar staff. There will be a few mature teenagers (who are below the set age, but would pass a capacity test) but we might say there is only minimal, if any, harm of their rights. The contrast with a medical practitioner dealing with a patient is stark. Here the rights at stake are significant. Also, the doctor has both the time and expertise to make the assessment. An argument based on efficiency seems inadequate to justify them not making an assessment.


The reader would be forgiven for thinking this chapter is rapidly moving towards a conclusion that the presumption of capacity must be abandoned. However, I think it can be rescued, at least in part. We need to go back to basics and consider why we require consent to treatment.

The starting point for the law is that a doctor who touches or treats a patient is committing a prima facie wrong (something that is potentially harmful, engages a legally protected interest or otherwise calls for an explanation). The doctor requires what the English Court of Appeal referred to as a “legal flak jacket”.38 That is some kind of legal authorisation for what they are doing. Most commonly, in the medical context, that will come from the consent of the patient. But why does the consent of a patient provide the justification? Surprisingly, there is relatively little written on that question in the literature. I would adopt the approach promoted

38 Re W (A Minor) [1993] Fam 64.

by Michelle Madden Dempsey.39 She argues that where a person consents to being touched, for example, this gives the other person an option so that if they so choose, they can act in that particular way. The consent allows the person to assume that all things considered the act is not contrary to the well-being of the consenter.40 It allows the actor to rely on P’s own assessment that the act is overall in P’s interests. In colloquial terms the actor can say:41

This is [P]’s decision. He’s an adult and can decide for himself whether he thinks the risk is worth it. In considering what to do, I will assume that his decision is the right one for him. After all, he is in a better position than I to judge his own well-being.

This has a number of benefits in this context. It rejects a formal understanding of consent where all that is required is the signing of a form or the utterance of the word “yes”. It requires the medical practitioner to engage with the patient, enabling the patient to make their own best interests assessment, but providing them with the information and support they need. Further, it encourages people, in their interactions with others, to seek to engage with them accepting their values. As Catriona Mackenzie puts it:42

The principle of respect for autonomy ... gives rise to an obligation to try to empathically engage with the other’s experience, to imagine what the other person’s situation is like for her, given her cares, values and concerns. In the context of patient care, it requires carers and medical staff to try to understand, from the patient’s perspective, her experience of illness, or of particular treatment options.

The consent of the patient is needed to provide the justification (or ‘flak jacket’) for the action. So while much of the discussion on autonomy from a philosophical perspective centres on the extent to which an individual is free and able to make a decision for themselves, in the context of the law the focus is slightly different. In law, capacity is relevant only to the extent to which a medical professional is entitled to rely on P’s decision as a justification for their otherwise wrongful act.

39 M Dempsey “Victimless Conduct and the Volenti Maxim: How Consent Works” (2013) 7 Criminal Law and Philosophy 11.

40 For further development of the argument see J Herring “Rape and the Definition of Consent” (2014) 26 National Law School of India Review 62.
41 Dempsey, above n 39, at 20.

42 C Mackenzie “Relational Autonomy, Normative Authority and Perfectionism” (2008) 39 Journal of Social Philosophy 512.

Capacity to consent in this model means that P is in a position to enable the doctor to reason in that permitted way: that the doctor can say that P has considered all the relevant issues and made an effective assessment of the treatment, sufficient for the doctor to be able to rely on it. We saw earlier reasons why we could not assume P has that kind of capacity. However, that earlier presentation was on an individualised understanding of autonomy.

I would, however, favour a more relational model. On our own I doubt many of us do have the ability to make an assessment of our own well-being of the kind required for an effective consent. However, in the context of good medical practise we do.

Remember first, how consent fits into the legal regime governing medical treatment. Consent is not the source of a right to treatment. The Court of Appeal in Burke v GMC captured this well:43

Autonomy and the right of self-determination do not entitle the patient to insist on receiving a particular medical treatment regardless of the nature of the treatment. Insofar as a doctor has a legal obligation to provide treatment this cannot be founded simply upon the fact that the patient demands it. The source of the duty lies elsewhere.

The Court of Appeal went on to say that the correct legal analysis is as follows. The medical professional makes an assessment of what treatment is most appropriate for the patient. That assessment is governed by the law on clinical negligence. The recommended treatment (or perhaps range of recommended) treatments are then proposed with a full explanation of them and of the patient’s medical condition.44 The patient can consent to or refuse the options offered. If there is a valid consent the medical professional may proceed with the procedure.

It is within this context that we must consider the nature of the presumption. This, I suggest, questions whether we need a presumption. If a patient approaches a doctor and explains their symptoms and listens to the doctor’s recommendation, then the doctor is entitled to find capacity. This behaviour is the behaviour of a typically capacitous person. The doctor here is not relying on a legal presumption but the behaviour of the patient in seeking medical help, explaining the symptoms and listening to the advice. All of this is evidence itself of capacity. There is no need for a presumption in such a case. The facts of the case provide evidence of capacity. Unless there is anything to suggest otherwise, it indicates the patient has

43 Burke v GMC [2005] 3 FCR 169 at [31].
44 Montgomery v Lanarkshire Health Board [2015] UKSC 11.

received from the doctor the relevant information, has asked the questions they need, and been able to make the decision they need to. We might assume, in the medical office, only in very rare cases will they be under such pressure that they are unable to make a decision and that inability will not be apparent to the medical professional.

This argument can be reinforced by considering the explanation for the role of consent suggested by Dempsey, referred to above. The key question is whether the doctor is entitled to determine whether P has made an assessment of their own best interests. Remember the doctor has already determined that the treatment is in the patient’s best interests, has provided the information and answered their questions. If there is no contrary indication, then the professional seems entitled to act on the basis that P has made a sound assessment of their own well-being.

It might help to contrast the position of a patient consenting to medical treatment with a patient consenting to sex. The man, let us say, proposing sex, is not normally in a good position to know whether the sex will be good for the proposed partner. He has no special expertise, and certainly no reason to presume he knows better than his partner about the benefits of sex. Medical treatment is different. The doctor has the expertise to assess the condition of the patient and recommend treatment. The patient has sought out her expertise and advice. More might be expected for consent on the Dempsey model of the man proposing sex than the medical professional proposing an operation.

But what about cases where P is refusing to consent? Here I suggest a patient who refuses consent indicates incapacity. Remember we are discussing cases where the capacity assessment produces an unclear answer on capacity. I suspect the most likely reason for this is that the patient refuses to co-operate with the assessment of capacity or cannot effectively explain to the doctor the reasons for their decision.45 Both of these might themselves be seen to be indicative of a lack of capacity, at least without further information. Remember too, we are dealing with a case where the medical professional has offered expert advice and the patient is refusing it. There are simply too many uncertainties for the medical professional to be sure this is a full refusal.

I would emphasise that it is a rebuttable presumption. If P has reasons for their refusal, then it is possible to imagine cases where the health care professional can assume that P has made a sound assessment of their best interests. An example might be where they explain that their religion does not permit this treatment.

45 S Hurst “When Patients Refuse Assessment of Decision-Making Capacity: How Should Clinicians Respond?” (2004) 164 Archives of Internal Medicine 1757.

Just to be clear, I am simply saying in the case of a refusal the doctor may presume a lack of consent. That does not, of course, automatically mean the treatment can be provided against P’s wishes. This is likely to require the use of force, and will be likely to cause emotional distress, which could be regarded as undignified. A very strong justification would be required for such harm.

In short, we can say this: where a doctor or other medical professional has made a proper assessment of what is in the patient’s best interests, explained the issues fully to the patient, replied appropriately to any questions, and the patient has then expressed a view, that is good evidence that the patient has capacity, unless there is evidence to the contrary. That means the medical professional has sufficient warrant to take P’s decision as an effective assessment of their best interests.

One of the attractions of this proposal is that it is relational. We do not need to rely on the traditional ‘doctor knows best model’ nor the more modern ‘patients know best model’. Rather it is the interaction between the patient and the doctor which generates the justification for the treatment. The patient, on their own, lacks the capacity to make decisions about medical treatment generally. Similarly, the doctor, without engaging with the patient, cannot make an assessment about this patient. However, together through discussion and interchange they can create the circumstances justifying the treatment.

This approach also deals to some extent with the concerns over the ways that capacity can be used against marginalised groups vulnerable to allegations of incapacity.46 As Nancy Knauer argues, a finding of incapacity is a “powerful tool of the state”, which measures people as incapacitous against “a supposedly neutral model that is coded to reflect majority interests and values.”47 However, the approach in this chapter acknowledges our mutual vulnerability. Our need for the advice, information and emotional support of others can produce a far more inclusive image. Seeing consent as being a co-operative approach, working towards an assessment of what P thinks is in P’s best interests, broadens the scope of who can give (and be presumed to give) consent.

Further, it makes it clear to medical professionals what they are doing when they are assessing capacity and determining the patient’s decision. They are not doing this from a distance: seeing the consent or refusal of a patient as being like a green or red light at the traffic lights. Rather this is an interactive process. It acknowledges that generally people are not good at assessing what is in someone

46 N Knauer “Defining Capacity: Balancing the Competing Interests of Autonomy and Need” (2003) 12 Temple Political & Civil Rights Law Review 321.
47 At 347.

else’s best interests. The clinician and patient need to work together to produce the necessary justification. As Atkins argues:48

Respect for autonomy is an acknowledgment of the limitations of our knowledge of other people and a willingness to incorporate that understanding into our worldviews. When we respect autonomy we don’t simply observe another’s freedom from a distance, as it were; we accede to our fundamental fallibility and epistemological humility. It is in recognition of the fact that we cannot experience from another’s perspective that we normally refrain from judging what will make another’s life good for them.

The medical professional must, therefore, in light of all the evidence, be satisfied not just that they have a “yes” from the patient, but that the patient has been able to make an assessment of their own best interests.


Peter Skegg, in his fascinating article, questioned the existence of the presumption of capacity and rightly so. He highlighted the ambiguities with it and the difficulties in using it as a presumption in medical practice. This chapter has supported that conclusion. It has also considered further whether the presumption can be justified. It has been argued that it cannot be justified as a statistical claim: it is implausible that a large majority of people have capacity to make important medical decisions. Similarly, it has been argued the presumption cannot be justified on the basis that it protects the rights of patients as in some cases it works against patients’ rights. However, it has been argued that if consent is understood in relational terms, if a medical professional has acted appropriately in explaining all the relevant issues to the patient, answered their questions, and supported them in their decision making, that is all strong evidence of consent, which can be relied upon to authorise the treatment. I have also argued that refusal to consent following an appropriate doctor-patient interchange suggests a lack of capacity, if the patient cannot offer any explanation for their refusal. Although it does not follow that the medical professional is therefore entitled to force treatment on the patient.

While I very much doubt Peter Skegg would agree with everything I have said in this article, it was inspired by him raising the simple question: ‘why presume competence?’ His observation that “the presumption of competence has proceeded

48 K Atkins “Autonomy and the Subjective Character of Experience” (2000) 17 Journal of Applied Philosophy 71 at 75.

without consideration of a clinician’s duty of care towards a patient”49 sparked much of my analysis. And that is the mark of a great academic: to ask the questions that no one asks and to get people thinking.

49 Skegg, above n 1, at 186.

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