Seldom do two books connect with such extraordinary resonance, seemingly without touching each other. Gere's book concerns the history of human experimentation, juggling greater-good utilitarianism with the rise of human rights and informed consent, casting a sharp critical eye over scientific and medical justifications for causing suffering on a small scale in the name of preventing human suffering writ large. It skewers the detachment of utilitarian calculus and points out that its victims reflect dominant ideological chauvinisms concerning race, class, disability and species. In its condemnation of the inhuman logics of behaviourism, and in its candid appraisal of the Tuskegee syphilis experiment over four decades, Gere warns starkly that the exploitative logic of experimental utility still lurks. At its heart, however, is a sustained critique of the capacity of philosophers to be able to divine the greater good, or to codify a balance sheet of pleasure and pain. When humans are reduced to statistical forecasts and political ideals, it is precisely the human that is missed.

This is where Lanzoni steps in, telling another story of twentieth-century human experimentation, carried out with the principal goal of understanding how and why humans feel and think into other humans, and why, often, they fail. Her history of empathy as a strictly twentieth- and twenty-first-century concept reveals the limits of understanding concerning the extension of human minds to others. Empathy, Lanzoni demonstrates, has not had a settled definition since its coinage in 1908, encompassing everything from the projection of the self to the reflection of the other, from a non-cognitive, automatic, fundamental quality of human being, to a situated, appraisal- and experience-based, phenomenon tied to culture. Empathy has been about movement, about aesthetics, about thoughts, about emotion and about politics. Only lately has it been about the material and mechanical mysteries of the brain itself.

Lanzoni's view of this neuroscientific research is subtly deployed, though she implicitly favours those views that see the brain as worlded and plastic, and empathy not as a simple, hard-wired system but as a complex dynamic process. What is strikingly clear is that for all the grand claims made by neuroscientists through the reductionist sensationalism of mass media, every claim has its counterclaim, every discovery has its cautionary note, and every leap forward has its echo of the past as dimly remembered knowledge. Empathy remains no nearer a clear definition than it has ever been in the course of a century, and yet an army of researchers remain on the quest to find ‘it’. The story of empathy is the story of scientists alienating themselves from their invention of the concept, which they theoretically objectify and then search after.

Yet if empathy's existence has been tenuous, this has not prevented a series of laments about its potential disappearance. Lanzoni shows that people worried about the loss of empathy before there was a stable definition of the thing. Psychologists and psychiatrists had deeply embedded it as a human universal before anybody had settled on how to measure or operationalize it, yet populists could claim to describe it and, in announcing its arrival on the social scene, mark its demise. The lack or loss of empathy has, it seems, often been a cipher for sociopolitical concerns about war, racism, misogyny and mistrust, held up as the social panacea, if only it could be found and honed.

Gere demonstrates that for utilitarianism's philosophical protagonists, from Hobbes to Bentham to Skinner, insight into human nature had always missed the actual human. Writing with sustained verve, in a compelling style, Gere explains that government along utilitarian lines was about guiding and limiting human nature, to make the best of a perceived desire for pleasure over and against human capacities to inflict pain in pursuit of it. This view never had firm biological roots, however much the idea depended on a biological foundation. Rather, biology was inferred from social and political behaviour, to which utilitarian ideas were a response. If there was a biological vision, it was of human nature in its most brutal form: rapacious, selfish, indulgent, animal. Gere makes much of an intellectual genealogy that transferred this bleak vision, and its ethical implications, from Britain to the United States, connecting Bentham to Bain to Thorndike to Skinner, such that ‘step by step … British utilitarianism evolved into American behaviorism, in a line of direct intellectual descent’ (p. 19). This vision of such a highly individuated transfer of knowledge is questionable, not least for what it leaves out of the account.

Darwinism is largely overlooked here, reduced to a couple of summary pages. If there was an experimental impetus in late nineteenth-century Britain, it was Darwin-inspired, and it was in the name of Darwinism that physiological experimentation in the United States discovered one of its founding rationales. This makes for a much more complex intellectual genealogy and alters the focus on utilitarianism, which, Gere acknowledges, was to Darwin a mere ‘secondary guide’ (p. 162). Darwin tried to reverse utilitarian pessimism about humanity. While he undeniably tried to make biology cohere with social observation, he nevertheless reached this point through natural history, seeing society as a product of evolution. If utilitarianism saw humans at their worst and tried to coerce them, Darwin saw humans at their best and tried to let the best flourish for the sake of the rest. Gere ultimately underplays this. She notes, in passing, that Herbert Spencer ultimately came to reject utilitarianism's moral calculus, on the basis that outcome prediction was just too fraught in a complex society. One had, in the end, to rely on the cognitive and emotional motivation of individual actors – the best representatives of nature – whose evolutionary prowess would better ensure a good outcome than any kind of statistical or demographic forecast. Darwinism explained these best representatives biologically. Insofar as experimental medicine cohered around a moral economy based in turn on a scientific understanding of sympathy, this understanding was expressed as a natural outcome of human evolution, limited to those men whose own intellectual adaptations had put them at the vanguard of civilizational change. Expressed this way, the argument of the greatest happiness for the greatest number had even more power, for it was not mere rhetoric. It was embodied in these men – scientific selves – who physically represented human progress and who pursued its furtherance through their research.

Lanzoni closes by describing empathy as a ‘technology of the self’ (p. 279), but the story she weaves is much more strikingly a politics of the self, where both agency and the capacity to know into or feel into others is contingent not simply on personal effort, but on training. Lanzoni's history, for all that it is about scientific experiment and practice, is most strikingly a political history of the ways in which boundaries have been drawn around types of self. This is evidenced most strongly in her chapter on civil rights-era politics, and activist claims that white people would not identify with black experience until compelled to do so – a question of policy, education, governance. As Arlie Russel Hochschild recently observed in Strangers in Their Own Land (2016), the tribal politics of contemporary America are defined by ‘empathy walls’. However much such walls seem to be natural, their erection took conscious political will, training, coercion, effort. It will take a similar political focus to knock them down.