In Benjamin Franklin's autobiography, he places the idea of temperance as the first step to achieving his conception of "moral perfection" (a glaringly ironic goal for a man who owned enslaved humans and supported the institution of slavery until very late in his life). According to Franklin, if one achieves the ability to control bodily desires, then one can continue to advance into mastering more complicated aspects of one's self and how one relates to himself and the world.

For Franklin, temperance essentially means moderation. For example, Franklin does not outright condemn the drinking of alcohol, but instead posits that temperance means that one does not drink to become drunk but to quench one's thirst.

Franklin explains in his autobiography that he arranges his thirteen virtues in a specific order based on the idea that the one that comes first will make it easier to attain the next one, and so on down the line. He puts temperance first, defining temperance narrowly as moderation in eating and drinking. Temperance heads the list because he decides that the "coolness and clearness of head" it requires will make it easier for him to practice silence, which is second on his list. As he puts it,

I judg'd it would be well not to distract my attention by attempting the whole at once, but to fix it on one of them at a time; and, when I should be master of that, then to proceed to another, and so on, till I should have gone thro' the thirteen; and, as the previous acquisition of some might facilitate the acquisition of certain others, I arrang'd them with that view, as they stand above.

Franklin states that being careful about not overindulging in food or drink requires keeping one's guard up constantly. That skill, of being ever alert to temptation, is necessary in order not to speak unnecessarily.

Franklin has clearly thought long and hard about the virtues he hopes to acquire—which include order, resolution, frugality, sincerity, and humility—and about the most efficient and practical ways to achieve these goals.

Franklin, as a man of the Enlightenment, believes fervently in the idea that man can become a perfect and rational being by adopting certain rules by which to live his life:

It was about this time that I conceived the bold and arduous project of arriving at moral perfection.  I wished to live without committing any fault at any time. . . .

This goal, of course, no matter how admirable may seem ambitious--perhaps impossible--to us in the 21stC., but men in the middle of the 18thC. absolutely believed that becoming morally perfect was not only possible but a positive duty.

When Franklin creates his list of moral virtues, he defines temperance, which appears first, as eating only until one is no longer hungry (and no more) and drinking only to satisfy thirst, not to become drunk.  In the introduction to the list of virtues, however, Franklin comments that temperance often includes

. . . moderating every other pleasure, appetite, inclination, or passion, bodily or mental. . . . 

Franklin decides, for purposes of clarity, to expand the list of virtues to create a clearer list of virtues and their accompanying rules, and therefore to limit temperance to food and drink.  This broader view of temperance, which extends to "every other passion, appetite, inclination," is consistent with the Enlightenment's view of the value of regulation in all aspects of life--physical, moral, spiritual.

For Franklin, then, temperance came first primarily because if one can control powerful bodily urges to eat and drink to excess, the control of other virtues--resolution, frugality, industry, among others--becomes more easily accomplished.  In other words, if men can exercise one virtue, they can exercise all virtues.

We debate whether Franklin took his own advice completely over the course of his life, but the importance of the list of virtues is that men in the 18thC. believe wholeheartedly that such virtues are attainable.