In the spirit of this debate, let me put fairness issues to one side and also adopt a liberal perspective that allows each of us to refuse potentially beneficial treatment in accordance with our beliefs. Against this background, I argue that we should value health interventions in terms of their impact upon how people think and feel about their lives. I contend that all public policies must ultimately aim to improve people’s lives and that the only person (with a few exceptions) who can really judge whether life goes well or not is the experiencing self.

The kind of experience or subjective well-being (SWB) I have in mind here is a very broad one, including not only hedonic pleasures and pains but also the less hedonic aspects of our experiences, such as engagement, purpose, and meaning. So, in valuing individual health benefits, I endorse a mental state account of well-being – but with a richer conception of mental state than is often characterized (and indeed caricatured) in much of the literature.

DH takes a rather different view and suggests that health benefits should be valued according to the degree to which they secure opportunities for people to pursue what is important to them. In sharp contrast to my position, DH argues that ‘subjective experience is not a good guide to well-being, and well-being is not what matters to public evaluation’. Like many of those who endorse an objective list account of well-being, DH contends that opportunities are important in their own right.

To me, functionings and capabilities are important only insofar as they provide useful proxies for better experiences. In some circumstances, they may even provide better proxies for future experiences than the current assessment of experiences would. However, I cannot see how something can be important if it is not expected to show up in someone’s experiences, somewhere, at some point. So, ultimately, we must consider the impact of health states on SWB even if we may sometimes use other proxies for estimating that impact.

Let us suppose that we wanted to follow DH’s approach to the valuation of health – either because opportunities are important in themselves or because they contribute to SWB. DH is a philosopher so it might be a bit unfair of me to ask him to spell out precisely how he would value health states according to their effect on ‘activity limitations’ but a little guidance would have helped us to get a clearer idea of the kind of activities and limitations he has in mind, how they should be weighed against one another, and, crucially, where they come from.

In general, I can see two sources of value: ‘philosopher kings’ and members of society. If we allow experts to decide, how can we be sure that they will come up with the right list, and how do we choose between the different lists that may be proposed by different experts? I cannot see an answer to these questions that does not require recourse to SWB. And if we allow society to decide, then surely we are bringing back all the problems with preferences (prejudices, focussing effects etc.) that DH and I both agree may not be the best basis for policy?

I am aware of some attempts to describe health and well-being in terms of its effects on capabilities, but, notwithstanding the quite serious methodological problems associated with generating objective lists, many – and arguably all – of the items on these various lists would show up in the richer kinds of measures of SWB that I recommend using to value the well-being consequences of different health states. So, the key challenge is better and more complete measures of SWB rather than the alleged jettisoning of SWB in favour of something that is conceptually questionable and empirically immeasurable.

In the first of their recommendations, SBU advocate that we develop our measures of SWB ‘to capture other important aspects of experience that go beyond mood’, and so there is total agreement between us here. Mat White, a psychologist at Plymouth, and I have recently conducted a study of 600 Germans using the day reconstruction method (DRM) to value the meaningfulness of activities as well as the pleasure associated with them. Our results are exactly as SBU (and many of you with children) might predict: spending time with children rates pretty highly in terms of meaning and, seemingly as a result, is generally judged to be pretty satisfying (it is also pretty enjoyable in our data too, in contrast to the results from the US). It is precisely this kind of information that we should be using to value health states.

I also fully endorse the third and final of SBU’s recommendations, which is to develop physiological measures of emotion and well-being. I would like to draw the reader’s attention to the work of Andrew Steptoe and colleagues at UCL, who are currently looking at the relationship between the DRM and health-related biological responses, e.g. cortisol and heart-rate variability.

Where I firmly disagree with SBU is in relation to their second recommendation that we should ‘develop an overarching, integrative theory of well-being that could be used to give some guidance on what should be important to most people’. There have been many attempts over the last two thousand years to develop such a theory and it is far from clear that they have got us very far. I am not at all optimistic that things will change in this regard. And note that SBU want to provide guidance on what should be important to most people, so perhaps they are closer to DH and the philosopher kings than first reading of their paper might suggest. The question is why anything should be important to someone unless it is expected to show up in their own SWB or in the SWB of someone else at some point?

It seems that SBU, along with DH, require external justification for why some things matter, and why some health states might matter more than others. I make no grand claims for the significance of anything – being able to hear, having Parkinson’s disease, or having children – beyond its effect on how people think and feel about their lives. To paraphrase Roger Crisp: ‘SWB seems just obviously worth having in life, and that is the end of it.’