Had it not been for the Fall, would all men have remained equal in the Garden of Eden? Thomas, in an article on “whether men were in the state of innocence” (Summa Theologiae 1.96.3, thinks not:
We must needs admit that in the primitive state there would have been some
inequality, at least as regards sex, because generation depends upon diversity of sex: and likewise as regards age; for some would have been born of others; nor would sexual union have been sterile.
Moreover, as regards the soul, there would have been inequality as to righteousness and knowledge. For man worked not of necessity, but of his own free-will, by virtue of which man can apply himself, more or less, to action, desire, or knowledge; hence some would have made a greater advance in virtue and knowledge than others.
There might also have been bodily disparity. For the human body was not entirely exempt from the laws of nature, so as not to receive from exterior sources more or less advantage and help: since indeed it was dependent on food wherewith to sustain life.
So we may say that, according to the climate, or the movement of the stars, some would have been born more robust in body than others, and also greater, and more beautiful, and all ways better disposed; so that, however, in those who were thus surpassed, there would have been no defect or fault either in soul or body.
In sum, men would have been dissimilar, and hence unequal, in sex, age, soul, body, and environment, yet all would have been without “defect or fault.” Thomas presses the point in the following article on “whether in the state of innocence man would have had dominion over man” (Summa Theologiae 1.96.4):
a man is the master of a free subject, by directing him either towards his proper welfare, or to the common good. Such a kind of mastership would have existed in the state of innocence between man and man, for two reasons. First, because man is naturally a social being, and so in the state of innocence he would have led a social life. Now a social life cannot exist among a number of people unless under the presidency of one to look after the common good; for many, as such, seek many things, whereas one attends only to one. Wherefore the Philosopher says, in the beginning of the Politics, that wherever many things are directed to one, we shall always find one at the head directing them. Secondly, if one man surpassed another in knowledge and virtue, this would not have been fitting unless these gifts conduced to the benefit of others, according to 1 Pet. 4:10, “As every man hath received grace, ministering the same one to another.” Wherefore Augustine says (De Civ. Dei xix, 14): “Just men command not by the love of domineering, but by the service of counsel”: and (De Civ. Dei xix, 15): “The natural order of things requires this; and thus did God make man.”
The inequality of men in the state of innocence leads to the dominion of some men over others even in a state of innocence.