Thomas Laqueur has written a lengthy history of masturbation.
Masturbation was not a big deal for the ancient Greeks and Romans, but it was certainly viewed as a "vice", albeit a minor one, because is was satirized in theater. In fact, the very word "satirize" derives from the Satyrs that were depicted as masturbating half beasts half men with giant sexual organs. The other people who are mocked as masturbating all the time were slaves (whose sexual life was presumably constrained). Hence masturbation was not viewed as something to be proud of. It probably also affected one's pride: if you masturbate, it means you can't get a woman, i.e. you are not virile enough. And the Greeks and Romans attached great importance to virility. There is no indication, however, that masturbation was viewed as a sin or as a health hazard.
The Catholic church changed that perception, and apparently it did so only one thousand years after being created, at a time when a reform movement was introducing a stricter code of behavior. At that point sex became a sin no matter what: the more pleasurable the more sinful. A less radical interpretation was that God had created sex so that humans could procreate but that was the only legitimate reason for sex. Any pleasure derived from it was due to the workings of the Devil, and any kind of sex not leading to procreation was "unnatural" and therefore very evil (an argument that the Catholic church still uses today to discourage contraceptives). Masturbation was therefore viewed as a sin, although never as evil as homosexuality or improper sex between spouses. In fact, the word "masturbation" did not exist until the 12th century.
Laqueur spends several pages to show that the Catholic church attacked masturbation too, but he almost proves the opposite: masturbation was a very minor concern. Both the most radical of Catholic moralists, Peter Damian, and the most influential, Thomas Aquina, hardly mention masturbation after listing it next to sodomy as an unnatural act that goes against the will of God. My guess is that, then as now, masturbation may have helped preserve the social order by decreasing the chances of extramarital sex in households and of homosexual intercourse in monasteries. The Catholic church felt compelled to ban any form of sex between husband and wife that did not lead to procreation (e.g. oral sex and sodomy, which were probably used, then as now, as forms of birth control) but less compelled to pick on solitary sex (or, for that matter, on prostitution, that was widely tolerated, and, again, can be viewed as helping marriage in that a man can cheat his wife with a prostitute instead of running away with another man's wife). Last but not least, masturbation was hard to detect: it's solitary and secretive.
The radicalization of Catholic views on sex almost certaily had to do with maintaining the social order, which meant marriage for ordinary people and celibacy for the priests. The social order was important not only inside the Christian world, but also outside: that sex-regulating social order came to be a sort of seal proving the conversion of "pagans" to Christianity. Hence its importance kept increasing as Christianity became more and more involved in secular, political and imperialistic affairs.
The sudden change in tone is visible in an anonymous pamphlet that began to circulate in London in about 1712: titled "Onania; or, The Heinous Sin of Self-Pollution, And All its Frightful Consequences, in both Sexes", it became so successful that it was reprinted several times by 1718 and then it was expanded by "A Supplement to Onania" in 1723. That book basically invented a new disease: it presented the dangers of masturbation in such terrifying ways that a whole new branch of medicine was born, offering expensive remedies to what had been an ancient and largely undisputed practice. Whether it increased or decreased the sense of shame traditionally associated with masturbation is not clear (Laqueur assumes too easily that it increased it) but it certainly compounded what had already been a moral problem. Even more influential was a follow-up published by the Swiss physician Samuel-August Tissot, "L'Onanisme" (1760), that was written in an even more scientific language and presented a long list of debilitating problems linked to masturbation. There was nothing religious about these tracts: they scientifically proved that European religious authorities had been right to ban masturbation but proved it without recurring to any religious argument.
Laqueur points out that the first half of the 18th century is when the Enlightenment began to take hold and offers an interpretation of the timing that i find little convincing: masturbation "came to represent the relationship between the individual and the social world". He doesn't point out that the 1712 treatise came out in Britain when erotica literature was beginning to find a broader audience, leading from Delarivier Manley's satirical erotic novel "Secret Memoirs and Manners of Several Persons of Quality, of both Sexes, From The New Atalantis" (1709) to the first bestseller in the genre, John Cleland's "Fanny Hill" (1748). Laqueur neglects the erotic literature of the time despite his own discovery that the author of "Onania" was probably the surgeon John Marten, known for his pornographic pamphlets. If there is a connection with the Enlightenment, then the question should be how and why the mood of the Enlightenment coincided with the boom in erotica in general.
Personally, i think that Laqueur lays down the correct factors for the boom of interest in (and persecution of) masturbation but then fails to do what an economist or a historian would have done: combine them and get the solution. Laqueur shows that the obsession with the disease of masturbation created a new market for both medicines and publications (hence there was an economic motivation to keep the issue alive); he shows that during that post-Newton age both institutions and public fostered and trusted scientific inquiry more than in previous ages (never mind that medical inquiry was hardly scientific at the time); he shows that a reading public was devouring books at an unprecedented rate; and he mentions in passing the popularity of erotica. Combine all of them, and i think there is a rational explanation to the question why masturbation suddenly became a hot topic, and why it was presented as a dangerous disease. To this day, movies and books sell more if they talk about an impending catastrophe.
Masturbation ended up being one of the victims of the Catholic moral crusade. Laqueur, determined to find a link with the new thinking of the Enlightenment, comes up with very creative explanations for why masturbation came to be feared in the 18th century, but seems to ignore the obvious one: masturbation is a way to desire other men's women (or other women's men), as in most cases the masturbating person is imagining a sexy counterpart, and therefore constitutes not only a sin but a direct breach of one of the ten commandments. Masturbation is also more easily related to other private acts like defecating, urinating and spitting, none of which was (or is) viewed as elegant. Whereas defecating and urinating cannot be avoided, spitting and masturbating can (to some extent). There might have been simple explanations for why physicians, authorities and scholars sided with the bigots in condemning masturbation. Laqueur mentions only in passing that the Society for the Reformation of Manners was founded in 1691 (21 years before the first libel against masturbation) with the purpose to fight profanity, adultery and prostitution. It doesn't seem too strange that moralists would begin targeting masturbation at about that time. There was a general idea of moral rectitude and, having to choose, most people back then decided that masturbation did not belong to the features of a moral person. Laqueur also mentions the association between addiction (e.g. alcoholism) and masturbation (often a form of addiction). This might certainly have alarmed physicians used to the damage caused by other kinds of addiction.
Instead Laqueur opts for a much more convoluted explanation: masturbation "entailed the willful mobilization of the imagination engaged in the endless creation of desire - fictive desire - that had at most a tangential relation to its real counterpart.... Masturbatory pleasure was dangerous because it was a sham version of real pleasure". Basically, the person who masturbates is wasting his or her imagination to produce selfish pleasure instead of producing, say, high art, and that waste would be seen by the people of the time as an unforgivable sin. I find this explanation hard to believe. According to Laqueur, the three features of masturbation (imagination, solitude and addiction) were perceived as threatening at the time of the Enlightenment. Laqueur dusts off Foucault's theory of the transition from tyrannical power of the absolutist regimes to the biopower of modern regimes: there is not a trajectory from slavery towards freedom but a shift from one from of repression to another form of repression, the latter being more subtle (less physical) but no less real. I am not sure why he brings this up because Laqueur then, wisely, focuses on the economic factors that Foucault neglected. What was new was not so much the "biopower" but the structure of the economy. It was an economic order in which people (both consumers and investors) were encouraged to be creative, selfish/greedy and to get addicted to credit. In other words, Laqueur points out similarities between masturbation and the new economy of the consumer society: the three features of masturbation (imagination, solitude and addiction) applied as well to the new economic order. Playing psychologist now, Laqueur argues that the anxiety about masturbation that arose at the time was channeling the "anxiety about a new political economic order". A mathematical mind would expect a conclusion such as: if one is disgraced (masturbation) then the other one should be too (consumerism). But a psychologist reads between the lines and can accommodate obvious contradictions: one is disgraced because the same psyche cannot refuse the other. Again, i find this explanation too complicated when there are simpler ones. I'm also not sure that i understand the timeline, since the economic boom that led to a consumer society started with James Watt's steam engine of 1766, half a century after the epoch that Laqueur is analyzing.
Next, Laqueur adds another theory, which requires an even bigger leap of faith. This one starts from another analogy: between the three features of masturbation (imagination, solitude and addiction) and private reading. He argues that private reading was taking off at about the same time. Quote: "Print culture... depended an encouraged precisely those qualities that made masturbation seem so threatening". I think that private reading preexisted since very ancient times. Laqueur would be better off talking about private writing (diaries) that does appear around this time, notably Samuel Pepys. Anyway, Laqueur points out that private reading (people reading books like "Onania") was "mobilized" to fight a private vice, but the result was that private reading actually publicized masturbation. So far so good. But then Laqueur makes a bold statement: "the cultural energy of certain sorts of reading... was the cultural energy of solitary sex". I guess that, if you believe in this identity, you may believe that it would cause masturbation to be considered a dangerous disease to the extent that one considers private reading a dangerous activity. In concluding, Laqueur summarizes his double-edge argument with a sentence that leaves me puzzled to say the least: "The onanist thus became the alter ego... of the modern self".
I suspect that, to start with, Laqueur exaggerates the extent to which learned people believed that masturbation was a "disease". Laqueur provides detailed accounts of anything written by both great and smaller minds of the time to warn about the health hazards caused by masturbation; but Laqueur does not do justice to the thinkers of the time because he does not list all the great minds (many more) who never spoke about the health hazards of masturbation: they were probably indifferent, knowing that it was all about nothing, just like they never spoke about many forms of superstition. Most of the learned men of the time probably rolled their eyes and shook their heads when they read or heard of the success of books like Tissot's, just like many of us roll our eyes and shake our heads when we hear the kind of junk presented as historical or scientific fact in today's bestselling novels or in today's Hollywood blockbusters that nonetheless go on to influence millions of people. The secular society of the Enlightenment probably shared the Catholic church's tolerance for the sin of masturbation. Just like prostitution, it helped maintain the social order by reducing the motivation to commit adultery and worse (rape).
If you are looking for psychological explanations for why the public was so easily convinced by a tiny minority of outspoken luminaries that masturbation was not only evil but caused diseases, the very nature of masturbation may help: like everything that is secret and invisible, it lends itself to all sorts of gossip. The way "Onania" became popular was very similar to the way the Web works in the early 21st century: readers wrote to the publisher, documenting more cases or confessing their addiction or asking for remedies; each new edition of the book included the "best" of these letters with further comments by the nameless author; each letter started a new thread. The gossip spread from edition to edition. Doctors actively encouraged the diffusion of the book because they were making money out of it: masturbators flocked to their doctors asking for cures based on what they read in "Onania". Just like today Hollywood movies publicize and indirectly foster the very "sins" that they portray, and then make even more money once these sins have spread, so did libels like "Onania" create a self-sustaining business cycle: social classes that had quietly masturbated for centuries suddenly became morbidly interested in the topic, and even those who didn't masturbate felt they had to because so many people were talking (or at least writing) about it. Laqueur mentions the rise of consumerism, the commodization of private life, and the coming of private reading, but does not connect the dots to visualize how the most harmless topic could snowball into a pseudo-scientific national conversation, whether it had to do with Scottish monsters or diseases caused by masturbation.
The next step in the popular interpretation of masturbation came with Freud and his psychoanalysis, that turned masturbation into one of the stages of psychological growth. Not evil, not dangerous, but simply an inevitable stage of life. By extrapolation, masturbation became a fundamental stage in the development of the whole human civilization. Quote: "Civilization depended on mastering masturbation".
And finally Laqueur sees the feminist movement giving masturbation a new meaning as a means of liberation from the traditional role of women as dependent on men. Laqueur argues that, even outside the small feminist crowd, the exact same three features of masturbation (imagination, solitude and addiction) came to be viewed in the 20th century in a benign way as leading to liberation. I am not sure how many people Laqueur knows who proudly proclaim they have just masturbated, but i guess i'm being picky.
The first half of the book is informative and factual. The second half is much more speculative and did not convince me. I feel there is a great book (or even two great books) hidden within that second half: one on pornography and one on private reading. Laqueur seems to have an incredible amount of knowledge about those topics and this book only uses it marginally. Obviously he is very familiar with these topics (a lot more than he is with Economics in general, with the industrial revolution in particular and with the birth of consumerism).
Whatever its shortcomings (and it all depends on whether you believe his theory or not), Laqueur's book constitutes a significant improvement over the previous tome on this topic, Jean Stengers and Anne Van Neck's "Masturbation - The History of a Great Terror" (1984).