With the coming of Christianity, however, a new understanding of what it means to be human came on the scene, although (in justice) Christianity cannot be said to have originated the idea. Christianity views itself as the fulfillment of Judaism, so it should come as no surprise that what we see in Christianity can be found also in Judaism; these ideas did not spring full grown out of Christianity. Credit rightfully goes to the Jews.
Judaism, however, was (by and large) viewed as being exclusively for Jews. Whatever the purely religious claims of Judaism and Christianity and the differences between them, the basic understanding of what it means to be human is essentially the same in both religions, as well as in Islam. In a temporal (that is, non-religious) sense, Christianity's contribution was to universalize Judaism's view of the human person and his role in society. The Law — meaning the natural moral law — was no longer to be understood or construed as something exclusively for Jews, but, when reduced to its essential precepts, as applying to the whole of mankind. As Jesus tried to make clear, He came to fulfill the Law, not to abolish it; not the tiniest particle of the Law would pass away.
Aside from the revolutionary idea that there is only one God, then, Judaism seems to have popularized the idea (also found in some of the Sophist philosophers, although, if we believe Aristotle, evidently poorly argued) that every human being is as fully human as every other human being. That is, each human being has the same capacity to acquire and develop virtue as every other human being. All human beings are thus fully human, and all human beings therefore meet the requirements for full participation in the common good.
This new view of humanity caused a serious problem when the philosophy of Aristotle was "rediscovered" in the 12th century. The philosophy of Aristotle was clearly based on logic and common sense, and yet appeared to be in conflict with the truths of revealed religion. In a line of argument that has been labeled "buffoonery," at least one commentator, Siger of Brabant, tried to explain away this problem by asserting that there are thus two different truths, one religious, and one scientific. In this Siger was ably opposed by Aquinas — although who is to be the ultimate victor appears to be in question to this day. As G. K. Chesterton described the matter,
Siger of Brabant said this: the Church must be right theologically, but she can be wrong scientifically. There are two truths; the truth of the supernatural world, and the truth of the natural world, which contradicts the supernatural world. While we are being naturalists, we can suppose that Christianity is all nonsense; but then, when we remember that we are Christians, we must admit that Christianity is true even if it is nonsense. In other words, Siger of Brabant split the human head in two, like the blow in an old legend of battle, and declared that a man has two minds, with one of which he must entirely believe and with the other may utterly disbelieve. (G. K. Chesterton, Saint Thomas Aquinas: "The Dumb Ox." New York: Image Books, 1956, 92-93.)Among other issues (which, however important, we will not get into here), Aristotle's conclusion that each human being has a different capacity to acquire and develop virtue and some have none, came into direct conflict with the Christian idea that all human beings have the same ("analogously complete") capacity to acquire and develop virtue — the equal opportunity and means to become "adopted children" of God. As America's Founding Fathers were to put it later, "All men are created equal."
In response to the oddities propounded by Siger of Brabant and to resolve the apparent paradox presented by Aristotelian philosophy, Aquinas posed his theory of "analogy of being." That is, each and every human being is "analogously complete" with every other human being. If you are human, you are fully human. If you are not human, you are fully not human. Whatever anything is, it is fully whatever it is, without qualification. If a thing is a particular thing, it is fully that thing. If it is not a thing, it is completely not that thing.
Aquinas's analogy of being is a logical development of Aristotle's "principle (or law) of contradiction" (or non-contradiction). This is, nothing can both "be" and "not be" at the same time. Thus, Aristotle's theory that human beings could have different capacities to acquire and develop virtue — the capacity to acquire and develop virtue being that which defines us as "human" — did not hold water in light of his own law of contradiction.
This breakthrough of Aquinas laid the groundwork for reconciling the individualistic and the collectivist views of society. This will be covered beginning in the next posting in this series.