MONOGENISM. — By monogenism is understood the unity of the human race inasmuch as it derives from a first man, Adam.
I. THEOLOGY
Holy Scripture, taken in its literal and most obvious sense, everywhere affirms the unity of origin of the human race. Gen. 2:5-7: “There was no man to till the earth... and man was made into a living soul”; ibid. 2:18: “And the Lord God said: It is not good that man should be alone; I will make him a help like unto himself”; ibid. 2:22: “The Lord God formed a woman and brought her to Adam”; ibid. 3:20: “Adam called his wife’s name Eve, because she was the mother of all living”; Wis. 10:10: “Wisdom preserved the first man formed by God to be the father of the human race, the only one created; she delivered him from his sin and gave him power to rule over all creatures.” In Acts 17:26-27, St. Paul, speaking to the Areopagus, declared: “From one man God made all the nations, that they should inhabit the whole earth.” 1 Cor. 15:45: “The first man, Adam, became a living soul.” Thus in the Bible Adam is taken as an individual name and not a collective one.But above all in Rom. 5:12-19, St. Paul expounds this doctrine at length in relation to original sin and the saving work of Jesus Christ: “As by one man sin entered into the world and by sin death, so also death passed to all men, because all have sinned... And so, as by the sin of one man condemnation came upon all men, so by the justice of one man justification unto life came to all men.”
Now, there can be no error in what is taught by Holy Scripture, of which God is the author. Therefore, when Holy Scripture is interpreted according to the rules of Catholic exegesis, every conclusion in favor of polygenism and against monogenism lacks foundation and must be excluded.
The same must be said of the teaching of the Church, and particularly of the Council of Trent, on the first man, on his state of original justice, his privileges (notably that of immortality), and on original sin transmitted to all men inasmuch as they descend from Adam (Denz.-U., 101, 133, 174, 176, 789, 791). The original unity of the human race is inseparable from the revealed doctrine of original sin. In the preparatory sessions of the Vatican Council (1st schema, 15; Collectio Lacensis, VII, col. 516), a canon had indeed been formulated, with a view to its definition: “If anyone denies that the whole human race descends from one protoparent Adam, let him be anathema.” Many theologians consider the proposition as “certain and proximate to faith.” A decree of the Biblical Commission of June 30, 1909 (Denz.-U., 2121-23) places the unity of the human race among the points of doctrine that touch “the foundations of the Christian religion.” Pius XII, in the encyclical Humani generis (Aug. 12, 1950: AAS, 42 [1950], pp. 561-78), explicitly confirms this by declaring inadmissible for a Catholic the polygenist opinion, which cannot be reconciled with the sources of Revelation.
For the polygenist theory and its refutation, V. POLYGENISM.
II. MONOGENISM ACCORDING TO SCIENCE
Scholars who deal with the origin of living beings are divided into monogenists and polygenists according as they admit that all organisms derive from a single original stock or that life initially appeared in a certain number of distinct forms, from which all other organisms, extinct or still living, would then have derived.With regard to the origin of organisms in general, opinions in the scientific field are very divided. In fact, there are good arguments both for monogenism (uniformity of fundamental biochemical and structural characteristics of all cells, both animal and plant) and for polygenism (lack of transitional forms between the major types of organization, i.e., between systematic types). For the most part, paleontologists currently limit their studies to reconstructing the individual phyla or lines of descent for the various groups of organisms (polyphyletic evolution) without investigating whether these phyla, as they go back in time, converge to a single common stock or not; which, at the present state of science, is impossible to establish.
With regard to the origin of man in particular, opinions are likewise divided. It can be said that the majority of scholars now agree in holding the unitary origin of all present human races (Homo sapiens) to be demonstrated, but the question is not so clear with regard to extinct races, whose anatomical characteristics sometimes differ so markedly from those of living races as to be referable to distinct species or even genera (Sinanthropus, Pithecanthropus, Africanthropus, Javanthropus, Palaeanthropus).