In the patristic and medieval understanding of the days of creation, the days that we’ve seen so far were considered as devoted to the creation of the basic structures of the universe. In this question and the next three we see an account of how those basic structures were filled out in the work of adornment, before the final questions of this section of the summa that consider the seventh day, God’s day of rest, and the six days of creation as a whole.
Why this Question Matters.
“And God said: Let there be lights made in the firmament of heaven, to divide the day and the night, and let them be for signs, and for seasons, and for days and years: to shine in the firmament of heaven, and to give light upon the earth. And it was so done. And God made two great lights: a greater light to rule the day; and a lesser light to rule the night: and the stars. And he set them in the firmament of heaven to shine upon the earth; and to rule the day and the night, and to divide the light and the darkness. And God saw that it was good. And the evening and morning were the fourth day.”
In this question Aquinas discusses the work of the fourth day of creation, the creation of the luminous heavenly bodies (that is, the sun the moon and the stars). As before, he argues that the place allotted to this act of creation in the general scheme is commensurate with that general scheme. He also discusses what these luminous heavenly bodies were created for and touches upon a medieval debate concerning whether they are animated.
The Thread of the Argument
A1: Following the pattern of earlier questions, Aquinas asks about the appropriateness of allotting the creation of the luminous heavenly bodies to the fourth day. The first four objections find arguments against this that are based on thinking about the general temporal order of what must have been produced before what. The fifth objection attacks the idea that the Sun and the Moon should be described as “two great lights”, on the grounds that medieval astronomers already considered other stars to be larger than the Sun and Moon.
Aquinas answers by giving a summary of the general structure of the account of creation given in Genesis. This structure is threefold: a work of creation in which an unfinished heaven and earth are produced; a work of distinction in which heaven and earth are completed in themselves; and a work of adornment in which things are put into heaven and earth. In particular, Aquinas identifies the second three day period of creation as describing the filling of the earth and heavens with moveable things. First among these moveable objects are the heavenly bodies that produce light: the sun, the moon and the stars. Aquinas pays special attention to the account of Augustine. In many ways Augustine’s account differs from the majority of the other Fathers of the Church; but here he is in accord with them. Augustine holds that the Sun, moon and stars are actually produced on the fourth day, not merely produced in their causes.
In answering the objections Aquinas identifies that in Augustine’s account the problems associated with temporal succession simply do not arise; Augustine considers the creation account as describing the natural structure of the world, not the temporal order of its coming to be. In the account of the other Church Fathers the objections are met by recognising the split between the work of creation and the work of distinction; things that might seem to be created too late in the Genesis account are actually created in inchoate form earlier on. Aquinas also makes mention of the teaching of John Chrysostom and of Basil the Great to the effect that some of the creation account takes into consideration the weakness of man in his propensity to fall into idolatry. If Moses had described certain things like the luminous heavenly bodies very early in the account of creation, this would have risked providing motivation for them to be considered as divine.
Finally, although other heavenly bodies might actually be larger than the sun and the moon, the sun and the moon have much greater influence on earthy things and they subtend a greater angle in the sky; it is quite appropriate for them to be described as the “two great lights”.
A2: What were the luminous heavenly bodies created for? The Genesis account gives a number of reasons for their creation, but the objections raise difficulties with each of these. Aquinas explains this passage by turning to a passage from Deuteronomy 4:19 where Moses warns of the danger of idolatry that may arise from an over-estimation of the role of these heavenly bodies. We recall from Ia.q65.a2 that there are four fundamental types of reason for any corporeal body: for its own proper activity; for the benefit of another creature; for the good of the cosmos as a whole; and for the glory of God. Aquinas explains that Moses only touches upon the benefits that accrue to the creature man from the luminous heavenly bodies in the Genesis passage, precisely to draw people away from the danger of idolatry.
When considered from the point of view of the benefit of humanity, the account given in Genesis is seen to be coherent. The heavenly bodies aid the sight of humans and guide their work; they drive the changing seasons; and they forecast favourable and unfavourable times for certain human occupations.
A3: The subject of the third article, whether the luminous heavenly bodies are animated, would seem to be fantastical to modern sensibilities. Why ever is Aquinas even asking this question? The reason for this question is that the idea that the heavenly bodies were in some sense alive or that they participated in some sort of world soul had a long history in platonic and neo-platonic thought; the reception of Arabic writings into the West renewed interest in the question.
Aquinas presents five objections that support the notion that the heavenly bodies are animated. The first three of these objections are based on various ways in which the heavenly bodies should be considered more noble than inanimate bodies: the luminous heavenly bodies adorn the heavens rather than the earth; the forms of the luminous heavenly bodies are clearly more noble than those of plants and animals; the sun and the moon are the causes of life on earth and a cause is more noble than its effects. This position in the hierarchy of nobility should be reflected by a corresponding position in the hierarchy of forms. The final two objections are based on the heavenly bodies as moving bodies: the movement of the heavenly bodies is a natural movement coming from within; they are in some sense self-moving. Therefore, as it is only living things that are self-moving, the heavenly bodies should be considered as associated with a living body.
After a very swift historical review of pre-Christian and Christian opinions on the matter, Aquinas attacks the thesis that the heavenly bodies are alive by analysing the reason for the union of soul with body in living things. The union of the soul with the body is for the benefit of the soul, not for that of the body in the same way that, more generally, form and matter unite for the benefit of form rather than matter. We must also recall that the nature of a soul is discovered through its activities; these are what it is for. The soul requires a body in order that the body may carry out some of the activities of the soul. So the nutritive soul requires a body to gain nourishment; a sensitive soul requires a body in order to sense. Similarly, a body provides the sensory images which lie at the foundation of intellective activity in the human being.
But these activities are simply not appropriate to a heavenly body. A heavenly body does not undergo growth through nourishment, so it makes no sense to claim that it has a nutritive soul. Similarly, there is no reason to associate a sensitive soul with a heavenly body (especially if, as Aquinas points out, it is formed from the fifth element that has nothing sensible in common with the earthly four elements). The only two operations of a soul that could be associated with a heavenly body are movement and understanding. Aquinas easily rules out the latter, so only the former, that of movement, is a possibility.
Having shown that movement is the only property of a soul that can be associated with the heavenly bodies, Aquinas argues that movement does not require the composition of a soul with a body. All that is required is some contact of power between an intellective soul and the heavenly body. What Aquinas is thinking here is that the heavenly bodies should be considered as the object of the prime mover; the unmoved first mover moves the heavenly bodies but there is no reason that these movements require that the first mover be united with the heavenly bodies as form is to matter. The apparent self-moving nature of the heavenly bodies should only be associated with the notion of a living body in an equivocal sense; Aquinas is willing to assert that the disagreements between those who assert that the heavenly bodies are living and those that do not is actually only a verbal disagreement due to this equivocation.
- The work of creation is threefold: the creation of the universe leads to the completion of its basic structures in the work of diversification and this in turn is followed by the work of adornment in which the universe is filled with moveable things.
- Augustine agrees with the other Fathers of the Church in that the luminous heavenly bodies are actually created on the fourth day rather than just being created in their causes.
- Some of the features of the creation account in Genesis may be explained by the author’s wish to avoid accidentally leading his readers into idolatry.
- The account of the creation of the luminous heavenly bodies in Genesis focusses on the benefits that accrue to mankind from them.
- Aquinas rules out the animation of heavenly bodies by arguing that out of all the things that an animating soul is for, the heavenly bodies only display movement. Furthermore, movement does not require the union of a soul, as form, with matter, as movement can be explained by some contact of power.