Abstract: If we want to maximise happiness we should establish what the full range of options are first and then pick the best ones. As no comprehensive list of options seems to exist I take a first pass at creating one in this chapter. This provides a check-list to ensure we don’t overlook any possibilities. I point out governments and ‘effective altruists’, private individuals who seek to do as much good as possible, tend only to focus on a subset of possible interventions: they try to improve things like wealth, health and education, rather than attempting more direct ways to make people happy, such as by teaching them how to think differently. This provides a prima facie reason to think we can find more effective ways to increase happiness than then status quo, although I don’t try to prove that here. I discuss some potential moral objections one might make to using various happiness interventions. [Note to reader: this will probably be chapter 10 in my thesis].
In this chapter I take a first pass at creating a taxonomy of ‘happiness interventions’, ways you can change someone’s life to increase their average happiness. I suggest there are six different happiness interventions, five of which can be split into direct and indirect versions. The former intend to bring about changes in conscious experience themselves, the latter do so through an intermediate step or as a by-product. The purpose of doing this is to have a checklist we, by which I mean anyone interested in increasing happiness, can use to ensure we haven’t forgotten to consider something.
It’s worth making two obvious observations to explain why such a taxonomy is helpful. First, there is typically more than one to make someone happier. Suppose, as a simple example, I want my parents to buy me a pony, and my lack of a pony is making me unhappy. Whilst buying me the pony is the clearest way to make me happier, it’s not the only way. An alternative would be for them change my mind about wanting the pony. Perhaps they point out how much time I’m going to have to spend looking after it, or how expensive it will be. Or they might buy me bicycle instead, knowing that if they did I would forget about the pony altogether. On assessing the options, my parents might decide the obvious way to increase my happiness – purchasing a pony – is not the best one.
Second, if we want to find the best way to increase happiness (or solve any problem in general), we should understand what the range of solutions are so we can pick the most suitable one(s). If we’ve not considered some of the options, we should worry we’re not going to make the optimal choice.
A third, less obvious observation, is that we tend not to construct and refer a full list of options, even though it’s easy to do so. Research in medicine and aviation shows that the use of checklists substantially reduces human errors as it overcomes cognitive biases and simple forgetfulness.
Despite the apparent usefulness of a taxonomy, to the best of my knowledge, no single comprehensive categorisation of the different types of happiness intervention currently exists. Certainly, philosophers, such as Singer and MacAskill, have argued what the world’s most important problems are; economists have examined factors associated with happiness. And psychologists and others have identified particular ways to increase happiness. But I have not yet come across a general framework of listing the different ways to increase happiness. This alone should make us concerned that we are not pursuing happiness as effectively as we might, a worry I claim is justified in later chapters when I present my suggestions for how best to maximise happiness.
Before setting out the different happiness interventions, I should make some remarks about happiness. For clarity, I understand ‘happiness’ in a roughly Benthamite tradition as positive conscious states: those that feel good the person experiencing them; ‘unhappiness’ is the converse. Hence the only two components to happiness are intensity (how good/bad something feels) and duration (how long the sensation lasts). There are other ways of defining happiness when considered as a psychological state – life satisfaction, ‘pro-attitudes’ or a desire to continue the present experience – but, as far as I can tell, nothing I say will turn on your preferred account of happiness. Some people doubt there is a single ‘good-bad’ dimension that unifies all experiences and permits a scale of happiness. Others doubt whether inter- or intrapersonal cardinal comparisons of happiness are possible or meaningful. I ignore these doubts here and assume we can make cardinal (inter- and intra-) comparisons of happiness: I imagine there is a fact of the matter as to how happy a person is at a given time, even if we don’t know what it is. To find the total happiness in a person’s existence is we simply sum how good/bad she felt at each of the moments of her life. To find her average happiness we divide the total happiness by the duration of her life.
I use the term ‘happiness intervention’ to refer to deliberate attempts to increase the average happiness in a life. Hence I mean to rule out those things which increase the duration of a life, as well as those things which might temporarily increase happiness but decrease it overall; for instance, a party that results in a very bad hangover.
It’s worth noting ‘happiness’ is sometimes used as a synonym for well-being, the theory of what makes someone’s life ultimately go well for them. I am only concerned with psychological states and will say nothing about well-being. Whilst I don’t assume hedonism, the view well-being consists only in happiness, I assume happiness is a part of all plausible theories what makes someone’s life go well. Hence what I say should be relevant whatever one’s account of well-being.
I’ll now list the different types of happiness intervention. Whilst all happiness interventions ultimately (by stipulated definition) work through changing a person’s conscious experiences, we can categorise them by what they initially change to do that. On this basis, I claim there are six types. As mentioned earlier, we can further divide these into direct and indirect interventions: the former into to change conscious experience themselves, the latter do so through an intermediate step or as a by-product. Where relevant, I’ll discuss the direct then the indirect versions and give an incomplete set of examples.
Six happiness interventions
Perhaps the most obvious intervention is to make people happier through external interventions that alter their objective circumstances. For instance, improving health, wealth, education, the physical environment in which people live, changing employment or relationship status, society around them, and so on.
These are external in the sense that they aim to change the world outside the person’s mind or body; rather than affecting conscious experiences directly, they act indirectly, altering the conditions of someone’s life in way that we expect will somehow make them happier. If my parents bought me the pony, but never told me about it, that would be an external change, a change to the facts of my life, but it wouldn’t impact my experiences and so my happiness.
Necessarily, all external interventions must be indirect. All the remaining five interventions can be split into direct and indirect types.
The second type of intervention is temporal: changing how people spend their time. The simple idea is that our happiness is often determined by our activities, and people could be happier if did more of what they liked and less of what they didn’t like, such as by re-allocating the division of time between friends, work, hobbies, children, exercising, commuting, sleeping, etc.
Direct temporal interventions are those where the change in time use causes greater happiness itself, for instance, someone leaving a miserable job for a more fulfilling one. An indirect temporal intervention might be learning to meditate: supposing you don’t enjoy learning to meditate itself, this might nevertheless increase your happiness by changing how think.
Internal interventions aim to change how a person thinks, such as by becoming more grateful or finding better way to process negative emotions such as stress and boredom. Research suggests we spend nearly half our time engaged in ‘mind wanderings’ – thoughts unrelated to the activity we are engaged in. Given how much time we spend in our heads, prima facie internal interventions are promising.
Whilst people may find the idea of becoming happier by changing how you think odd, it’s worth pointing out the main contemporary method of treating mental health conditions, such as depression and anxiety, is through psychotherapeutic methods like Cognitive Behavioural Therapy (‘CBT’) or Mindfulness-Based Stress Reduction (‘MBSR’)., These methods are shown to be effective and work not by changing the objective facts on someone’s life, but teaching them how to spot (or accept) negative thinking patterns and then challenge them. There’s also evidence these same methods can improve the happiness of ‘non-clinical’ populations (i.e. ‘normal’ people without mental health conditions). Historically, the tradition of deliberating trying to change how you think can be traced as far as the Stoic philosophers of Ancient Greece and Rome.
The examples I’ve given above are direct internal interventions. An indirect example would be academic education; learning chemistry may change what you think, but it isn’t an attempt to change how you think in a way that makes you happier.
Fourth, we can use substances that chemically react with our bodies to change how we feel. The most obvious example of this, so obvious we may not think of it as a chemical producing a sensation, would be food and drink. Others in this category could be, but aren’t limited to, alcohol, caffeine, painkillers, anti-depressants as well as what we normally call ‘drugs’: typically illegal substances such as cannabis, MDMA (ecstasy), cocaine, heroin, and so on. I say these ‘could be’ happiness interventions because we might doubt whether they do or don’t successfully increase average happiness. Perhaps counter-intuitively, recent research suggests several illegal drugs may actually be effective treatments for mental illnesses: LSD seems to help with anxiety, psilocybin (‘magic mushrooms’) and ketamine with depression, and MDMA with Post-Traumatic Stress Disorder (PTSD).
Indirect chemical interventions would be things like antibiotics or the contraceptive pill. The former removes disease, the latter permits more sex, both of which presumably increase happiness, but the happiness is a by-product how those chemicals change our lives.
The fifth option is physically interacting with the body or brain to alter happiness. Everyday examples physical happiness interventions might be hugging or sex, whereas a physical unhappiness intervention would be pain, for instance from stubbing your toe. Medical surgeries that relieve pain would count as a direct physical intervention, whereas one that restored sight would constitute an indirect intervention.
Focusing on direct brain stimulation, the most popular example in public imagination is of rats or humans repeatedly pressing levers to receive tiny shocks via electrodes implanted deep in their brain. There’s some doubt as to whether this produces happiness: neuroscientists distinguish ‘liking’, a feeling of pleasure, from ‘wanting’, a desire or motivation or receive stimulation, and claim use different parts of the brain anatomy.  As this sort of experiments only seem to activate the ‘wanting’ circuits, it’s unclear if these do generate a positive feeling and so increase happiness. More promisingly, there is some evidence of using repetitive transcranial magnetic stimulation (rTMS) to treat depression, and of deep brain stimulation (DBS) to treat chronic pain.
Finally, the sixth happiness intervention would be biological: genetically engineering humans to increase our happiness. The direct version would be hedonic enhancement: changing someone’s DNA so they feel more joy and less sadness. Indirect versions might be things like moral and cognitive enhancement which focus on improving ethical and intellectual abilities, respectively. Whilst the possibilities of genetically engineering in general are well-known, such as creating faster growing, diseases resistant animals and crops, I’m currently unaware of research looking at hedonic enhancement. Nevertheless, it is a clear theoretical possibility.
How do the happiness interventions fit together?
Having set out the happiness interventions, it’s worth clarifying how they interact. As mentioned earlier, happiness interventions are distinguished by what they target to improve average happiness. In doing so, an intervention in one area may work through other types of interventions before it has an impact on conscious experience. Whilst owning a pony is an external change, the happiness it gives me might come from the joy of knowing or believing I own a pony (internal) as well as the thrill of being able to spend time riding it instead of sitting in my room imagining I was riding a pony (temporal). Nevertheless, it’s an external intervention as that’s what was targeted. If my parents had simply convinced me I did own a pony, that would be an internal intervention.
I should point out that the structure of the taxonomy isn’t itself important. Its purpose is to provide a check list those trying increase happiness can consult to ensure they haven’t forgotten something obvious. We may later decide there are three types of interventions, or the distinction between direct and indirect is unhelpful. I chose the six types and the direct/indirect split because that seemed to offer relatively distinct pathways by which happiness could be altered.
Which happiness interventions do we use currently?
In general, most efforts to improve the world mostly seem to focus on using indirect external, internal, physical and chemical interventions. This seems obvious so I won’t labour the point, but governments tend to focus on things like growing the economy or reducing crime (both external), providing education (indirect internal) and making people healthy (indirect physical or chemical, depending on treatment). They do consider direct internal and chemical interventions to treat problems, like mental health and physical pain, but they don’t try to directly increase happiness in the general population through changing how people spend their time or think (temporal and internal). Clearly, governments in the real world don’t insist people take happiness-inducing drugs in the way the fictional governments in Huxley’s Brave New World readily hand out soma to their citizens. Presently, genetic editing to remove known health conditions is controversial; hedonic enhancement seems unthinkable. I should state I’m not making a moral case here for what governments should do, simply stating which happiness interventions they use at the moment.
There’s a similar story for effective altruism. Peter Singer and Will MacAskill argue the best ways for individuals to do good, if they want to benefit currently existing humans, is by giving money directly or providing health treatments, such as malaria resistant bednets, to those in the developing world. As far as I can tell, at the time of writing this, neither suggests any direct happiness interventions.
What can the taxonomy tell us about the best ways to increase happiness?
As our current focus is mostly on indirect interventions, one thought is we should try to increase happiness directly instead and we should explore new ways to do that. Whilst I’ll argue in later chapters this is correct conclusion, it’s not possible to demonstrate this simply from the taxonomy itself. A list of options by itself doesn’t tell you which the best one(s) is(/are). For instance, it might turn out it’s impossible to make people happier by retraining how they think. Or it might be possible to do that, but it’s nevertheless more cost-effective just to give people money and let them use it however they want.
What we need in addition is an understanding of how happiness works in general (which I discuss in chapter 7) and what biggest opportunities to increase happiness are (which is chapter 9). With that information, we can assess how effectively the different interventions might increase happiness, and draw some overall conclusions about what to do. This is the subject of the next chapter.
In this chapter, I’ve only been interested in different ways to increase happiness. However, it’s possible to object that, even if we could increase happiness by some method, it would nevertheless be morally valueless, or even wrong, to do so. I want to make a brief comment on the moral value of the interventions on my own moral theory. Then I’ll comment, again briefly, on other potential objections.
In part 1 of the thesis I endorsed classical utilitarianism, the view on which all that matters morally is happiness and we ought to bring about as much of it as possible. However, I only adopted this in fixed-population cases, where the number and identities of people don’t change. When it came to variable-population cases, I argued for necessitarianism as the correct population axiology (an ‘axiology’ is a ranking of outcomes in terms of their overall goodness). Necessitarianism holds the only people who morally ‘count’ are those who exist in all outcomes under consideration, i.e. whose existence is not dependent on what we choose to do. On necessitarianism, there is no moral value in creating new people as such people don’t necessarily exist.
The value of the first five happiness interventions – external, temporal, internal, chemical and physical – is straightforward. These all involve already existing people and so are morally good solely in proportion to how much happiness they increase.
The sixth intervention, genetically engineering people to be happier, is much less clear. Suppose a government decided to fund hedonic enhancement for new children. This would result in the non-identity problem I discussed in chapter 5: presuming it affected the timing of reproduction even slightly, the government’s offer would cause different children to born. On necessitarianism, the government doesn’t do any good by creating different, happier people, at least as far as the value solely regarding those new goes. Of course, necessitarians could justify hedonic gene editing on the basis it’s better for other people; for instance, it could be the currently (and thus necessarily) existing people in society would be happier if the next generation were edited to be more joyful.
However, there are other scenarios in which hedonic enhancement might be good. Suppose a pair of stubborn parents created a zygote (i.e. the sperm and egg are joined together) and are considering genetically engineering it to be happier. They might insist this zygote exists necessarily by refusing to accept there are any alternatives where they don’t cause it to become an adult, in just the same way parents might insist there is no possibility in which they kill their 10-year old child and therefore it’s good to improve the 10-year old’s welfare. In such a case, it might be good to modify the zygote. The challenge for necessitarianism, as I discussed in chapter 5, is one of choice-set dependence: further specification is required to say whether the stubborn parents’ child counts as existing in all circumstances under consideration or not. I’m unsure exactly how the relevant choice set should be defined so leave the problem here.
I should point out the same problem regarding biological interventions doesn’t emerge for total utilitarianism, the view on which the best outcome is the one with the greatest amount of happiness, as creating happy lives is good on this view. Hence genetically engineering people to be happier is good in proportion to how much additional happiness it generates.
Another way to question the value of one (or more) of the happiness intervention would be to deny hedonism, the view that well-being consists solely in happiness. For instance, Nozick famously argued that if one was made happier inauthentically by an experience machine that gave you any sensation you wanted, that would not improve your well-being. Perhaps non-hedonists would object to certain physical or chemical happiness interventions. I’ve already defended hedonism in chapter 1 so won’t do so again here.
Another objection non-consequentialists, those who believe you do not always have to bring about the best outcome, could make is it would wrong to make someone happier against their will, for instance by secretly drugging them. I should note concerns of this sort aren’t objections to a happiness interventions themselves, only to acting against someone’s will. A non-consequentialist would need a further argument to say it was wrong for someone to voluntarily give themselves a happiness-inducing drug.
The final thing I want to mention is that the morality of genetic editing, of which biological happiness interventions are a part, remains controversial amongst non-consequentialists (e.g. see discussion in Savulescu and Kahane). As I am not a non-consequentialist I merely note it and move on to the conclusion.
In this chapter, I’ve proposed a taxonomy of happiness intervention, identifying six different ways to increase happiness, which can further we split into direct and indirect versions. I claim typical attempts to improve the world use only a subset of the available options. I suggested this was an oversight, but didn’t make any claims about which happiness interventions are better than others as that requires further empirical support. I discussed some moral objections one could raise to different happiness interventions.
 E.g. see Atul Gawande, The Checklist Manifesto : How to Get Things Right (Profile, 2010); Alan M Wolff, Sally A Taylor, and Janette F McCabe, “Using Checklists and Reminders in Clinical Pathways to Improve Hospital Inpatient Care.,” The Medical Journal of Australia 181, no. 8 (October 18, 2004): 428–31, http://www.ncbi.nlm.nih.gov/pubmed/15487958.
 W MacAskill, Doing Good Better: Effective Altruism and a Radical New Way to Make a Difference, 2015; Peter Singer, The Most Good You Can Do: How Effective Altruism Is Changing Ideas about Living Ethically (Text Publishing, 2015).
 E.g. see the World Happiness Report: J Helliwell, R Layard, and J Sachs, “World Happiness Report 2017,” 2017, http://worldhappiness.report/ed/2017/. or Paul Dolan, Tessa Peasgood, and Mathew White, “Do We Really Know What Makes Us Happy? A Review of the Economic Literature on the Factors Associated with Subjective Well-Being,” Journal of Economic Psychology 29, no. 1 (2008): 94 <last_page> 122, doi:10.1016/j.joep.2007.09.001.
 E.g. Linda Bolier et al., “Positive Psychology Interventions: A Meta-Analysis of Randomized Controlled Studies,” BMC Public Health 13, no. 1 (2013): 1.
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 This contrast with JS Mill, Utilitarianism, 1861. who claimed there are ‘higher’ and ‘lower’ pleasures.
 Leonard Wayne Sumner, Welfare, Happiness, and Ethics (Clarendon Press, 1996).
 Fred Feldman, What Is This Thing Called Happiness? (Oxford University Press, 2010).
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 See e.g. Martha C. Nussbaum, “Who Is the Happy Warrior? Philosophy, Happiness Research, and Public Policy,” International Review of Economics 59, no. 4 (December 23, 2012): 335–61, doi:10.1007/s12232-012-0168-7. for criticism and Roger Crisp, “Hedonism Reconsidered,” Philosophy and Phenomenological Research 73, no. 3 (2006): 619–45. for a defence.
 The most famous is Lionel Robbins, An Essay on the Nature and Significance of Economic Science, (London: Macmillan, 1932), http://www.worldcat.org/title/essay-on-the-nature-significance-of-economic-science/oclc/838285..
 This rules out, for instance, weighting the moments of your death more heavily than earlier moment of your life, or supposing that later moments of your life can retrospectively reduce how much happiness you experienced earlier.
 Derek Parfit, Reasons and Persons (OUP Oxford, 1984).
 Matthew A. Killingsworth and Daniel T. Gilbert, “A Wandering Mind Is an Unhappy Mind,” Science 330, no. 6006 (2010), http://science.sciencemag.org/content/330/6006/932.full. find mind wanderings occurred in 46.9% of randomly sampled experiences.
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 E.g. Epictetus in RF Dobbin, “Epictetus: Discourses, Book 1,” 2007, https://philpapers.org/rec/DOBEDB.
 Peter Gasser, Katharina Kirchner, and Torsten Passie, “LSD-Assisted Psychotherapy for Anxiety Associated with a Life-Threatening Disease: A Qualitative Study of Acute and Sustained Subjective Effects,” Journal of Psychopharmacology 29, no. 1 (January 2015): 57–68, doi:10.1177/0269881114555249.
 See e.g. Robin L Carhart-Harris et al., “Psilocybin with Psychological Support for Treatment-Resistant Depression: An Open-Label Feasibility Study,” The Lancet Psychiatry 3, no. 7 (July 2016): 619–27, doi:10.1016/S2215-0366(16)30065-7. on psilocybin and Polly Taylor et al., “Ketamine—the Real Perspective,” The Lancet 387, no. 10025 (2016): 1271–72, doi:10.1016/S0140-6736(16)00681-4; Rebecca B. Price et al., “Effects of Intravenous Ketamine on Explicit and Implicit Measures of Suicidality in Treatment-Resistant Depression,” Biological Psychiatry, vol. 66, 2009, doi:10.1016/j.biopsych.2009.04.029; Olivia F O’Leary, Timothy G Dinan, and John F Cryan, “Faster, Better, Stronger: Towards New Antidepressant Therapeutic Strategies,” European Journal of Pharmacology 753 (April 2015): 32–50, doi:10.1016/j.ejphar.2014.07.046. on ketamine.
 Peter Oehen et al., “A Randomized, Controlled Pilot Study of MDMA (±3,4-Methylenedioxymethamphetamine)-Assisted Psychotherapy for Treatment of Resistant, Chronic Post-Traumatic Stress Disorder (PTSD),” Journal of Psychopharmacology 27, no. 1 (January 2013): 40–52, doi:10.1177/0269881112464827.
 See (Olds & Milner, 1954) and Charles E. Moan and Robert G. Heath, “Septal Stimulation for the Initiation of Heterosexual Behavior in a Homosexual Male,” Journal of Behavior Therapy and Experimental Psychiatry 3, no. 1 (March 1972): 23–30, doi:10.1016/0005-7916(72)90029-8., respectively.
 Morten L Kringelbach and Kent C Berridge, “The Functional Neuroanatomy of Pleasure and Happiness.,” Discovery Medicine 9, no. 49 (June 2010): 579–87, http://www.ncbi.nlm.nih.gov/pubmed/20587348.
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 Morten L. Kringelbach et al., “Deep Brain Stimulation for Chronic Pain Investigated with Magnetoencephalography,” NeuroReport 18, no. 3 (February 12, 2007): 223–28, doi:10.1097/WNR.0b013e328010dc3d.
 Aldous Huxley, Brave New World, 1932.
 MacAskill, Doing Good Better: Effective Altruism and a Radical New Way to Make a Difference; Singer, The Most Good You Can Do: How Effective Altruism Is Changing Ideas about Living Ethically.
 R Nozick, Anarchy, State, and Utopia, 1974.
 J Savulescu and G Kahane, “The Moral Obligation to Create Children with the Best Chance in Life,” Bioethics 23, no. 5 (June 2009): 274–90, doi:10.1111/j.1467-8519.2008.00687.x.