The Measure of Multitude: Population in Medieval Thought (review)

On page 358, Peter Biller, a recognized authority on medieval demographic thought, mused that, were History a laboratory science, he would have a control group to measure the impact of Aristotle’s advocacy in Politics for population regulation in a well-directed city. As it was, Biller measured how the concerns of medieval theorists (such as Peter of Auvergne and Albert) turned towards restricting populations because of the experiences of their generation. A control group would have been theorists who lived in a time (as actually happened following the Black Death) when there was a perception of under population. Without a laboratory control, Biller’s study draws evidence from a wide variety of sources; he concludes that some medieval theorists thought simultaneously on issues ranging from the morality of individual’s sexual acts to global strategies regarding population sizes. There was, he asserts, a notion of the “common good” incorporated within discussion in canon texts about marriage and virginity. The soul of the individual and the welfare of the multitude were related.

In his Introduction and Epigraph, Biller acknowledges schizophrenia about applying modern terminology when examining medieval thought; for example, does “multitude” equal “population”? What about loaded words, such as birth control, coitus interruptus, contraception, and, although Biller does not say it, family planning? The question is how to relate medieval concepts to “dangerous modern vocabulary” (p. 137). This is more than a semantic and methodological problem, but Biller bridges the divides with scholarly sensitivity and produces some surprising conclusions.

Up until the early twelfth century theological and canon-law treatises possessed a traditional, formulaic approach to marriage but by the next century, as a result of experiences with Arabs, Greeks, and internal dissidents (e.g., Cathars), an awareness about diversity in the “marriage-system” (coniugium) modified European perceptions. William of Auvergne’s lenghty treatise on marriage has “extraordinary distinctiveness”; he studied Islamic practices (multiple wives) and concentrated on fertility. Biller attributes William’s knowledge to a “direct pastoral experience” which raised theoretical questions with practical implications about ideal family size. What happens when Muslim families populate the world while Christian families shrink? William attributed Muslim multitudes to favorable geography, not fertility. William of Auxerre (ca. 1215–1229), Bonaventure, and Peter the Lombard dealt with “sex-ratio,” the earliest being William. The ratio, Biller claims, was a “topic of discussion” in Paris and by the fourteenth century at least one city measured the ratio at baptism.

The population increase led to speculation about the perception of marriage and sufficient population. The injunction “increase and multiply” conveyed a notion of the “common good.” William of Auxerre declared marriage to be “by way of remedy, not precept.” Concern for religious celibacy and procreation duties collided with the New Aristotle where the ideal city-size was subject to the guardians’ welfare for all. The size of the city was subject to enlightened manipulation for higher goals. Biller posits that new thinking about population developed in the decades around 1300. In examining the medical documents for contraceptive and abortion measures and infanticide practices, Biller faults earlier studies by John Noonan (“modern liberal Catholic campaigning” on birth-control), by this reviewer (“uncritical enthusiasm” for medical techniques), and by others who necessarily depend on “distortion” produced by translating medieval Latin into “dangerous modern vocabulary.” Biller’s evidence is impressive, honestly presented, and adroitly argued that practical pastoral experiences caused thinkers to examine individual morality issues related to sexuality in light of “circumstances,” such as the economic ability of family to maintain support. The divide between the modern conception of “birth-control” and medieval thought had narrowed by around 1300.

Biller culls his data from a wide variety of medieval sources. The encyclopedists (Bartholomew, Vincent of Beauvais, etc.), travelers (Marco Polo), and missions by mendicant monks had a world-view of populations. Europeans became aware of the population size of China, the Mongul and Muslim Empires, and the relationship between adequate size and power for survival. Medieval writers learned...