Preservation of food from rot may have had no alternative, but human filth was not incumbent. Given sweat, vomit, defecation and urination, sexual emission and the menstrual flow of women, the human body is not a clean machine, and when people are crowded together in an enclosed space, its effluents can create a degree of unpleasantness raised to the extreme. Means of improving hygiene and sanitation could have been devised if they had been wanted, for men can usually work out the technical means to obtain what is truly desired unless the refrain "it can't be done" becomes their guide.If living conditions provided for a fighting sailor were so nauseating, imagine what obtained in the hold of the ships that carried African slaves across the Atlantic. Pecuniary profit trumped all, for the slave merchants, and for the long-suffering sailors who could expect a share -- pittance that it was -- of the prizes of war. The captain of a ship-of-the line might fairly expect to become rich from the spoils of conquest, and some did. Greed, power and war held sway. The milk of human kindness had nothing to do with it.
How was it then that by the end of the following century it had become the acknowledged responsibility of governments to provide citizens -- on land or sea -- with clean water and sanitation? A sea-change had occurred in public expectations. "It can't be done" gave way to "can do." Even the poorest citizen in the developed countries can now expect to turn a tap and flush a toilet, receive medical care in a clean hospital, and flick a switch to obtain refrigeration, heat, and light. A sailor on a modern warship expects no less, and enjoys pretty much all the comforts of home, and maybe then some.
It was not religion that changed the picture. As Tuchman's book makes clear, religion managed to accommodate itself to any barbarism; dogma is the natural ally of the status quo. Rather, the "can do" spirit grew out of empiricism. Since the Scientific Revolution of the 16th and 17th centuries, and especially with the Enlightenment, a scent of progress was in the air that became in the 19th century the prevailing aroma. Darwin's notion of evolution was more than biology; it was a corollary of the time. The future beckoned, and fixed dogma conceded to an open-ended search for truth.
Mercantile greed, raw political power, and warfare are of course still with us, but they are no longer celebrated as defining dimensions of national identity, as they were in Europe at the time of the American Revolution. For that we can thank the philosophers and scientists of the Enlightenment who dared to question prevailing orthodoxies.