QUESTION 68: ON THE WORK OF THE SECOND DAY
We must next consider the work of the second day. Under this head there
are four points of inquiry:
(1) Whether the firmament was made on the second day?
(2) Whether there are waters above the firmament?
(3) Whether the firmament divides waters from waters?
(4) Whether there is more than one heaven?
Article 1: Whether the firmament was made on the second day?
Objection 1: It would seem that the firmament was not made on the second day.
For it is said (Gn. 1:8): "God called the firmament heaven." But the
heaven existed before days, as is clear from the words, "In the beginning
God created heaven and earth." Therefore the firmament was not made on
the second day.
Objection 2: Further, the work of the six days is ordered conformably to the
order of Divine wisdom. Now it would ill become the Divine wisdom to make
afterwards that which is naturally first. But though the firmament
naturally precedes the earth and the waters, these are mentioned before
the formation of light, which was on the first day. Therefore the
firmament was not made on the second day.
Objection 3: Further, all that was made in the six days was formed out of
matter created before days began. But the firmament cannot have been
formed out of pre-existing matter, for if so it would be liable to
generation and corruption. Therefore the firmament was not made on the
On the contrary, It is written (Gn. 1:6): "God said: let there be a
firmament," and further on (verse 8); "And the evening and morning were
the second day."
I answer that, In discussing questions of this kind two rules are to
observed, as Augustine teaches (Gen. ad lit. i, 18). The first is, to
hold the truth of Scripture without wavering. The second is that since
Holy Scripture can be explained in a multiplicity of senses, one should
adhere to a particular explanation, only in such measure as to be ready
to abandon it, if it be proved with certainty to be false; lest Holy
Scripture be exposed to the ridicule of unbelievers, and obstacles be
placed to their believing.
We say, therefore, that the words which speak of the firmament as made
on the second day can be understood in two senses. They may be
understood, first, of the starry firmament, on which point it is
necessary to set forth the different opinions of philosophers. Some of
these believed it to be composed of the elements; and this was the
opinion of Empedocles, who, however, held further that the body of the
firmament was not susceptible of dissolution, because its parts are, so
to say, not in disunion, but in harmony. Others held the firmament to be
of the nature of the four elements, not, indeed, compounded of them, but
being as it were a simple element. Such was the opinion of Plato, who
held that element to be fire. Others, again, have held that the heaven is
not of the nature of the four elements, but is itself a fifth body,
existing over and above these. This is the opinion of Aristotle (De Coel.
i, text. 6,32).
According to the first opinion, it may, strictly speaking, be granted
that the firmament was made, even as to substance, on the second day. For
it is part of the work of creation to produce the substance of the
elements, while it belongs to the work of distinction and adornment to
give forms to the elements that pre-exist.
But the belief that the firmament was made, as to its substance, on the
second day is incompatible with the opinion of Plato, according to whom
the making of the firmament implies the production of the element of
fire. This production, however, belongs to the work of creation, at
least, according to those who hold that formlessness of matter preceded
in time its formation, since the first form received by matter is the
Still less compatible with the belief that the substance of the
firmament was produced on the second day is the opinion of Aristotle,
seeing that the mention of days denotes succession of time, whereas the
firmament, being naturally incorruptible, is of a matter not susceptible
of change of form; wherefore it could not be made out of matter existing
antecedently in time.
Hence to produce the substance of the firmament belongs to the work of
creation. But its formation, in some degree, belongs to the second day,
according to both opinions: for as Dionysius says (Div. Nom. iv), the
light of the sun was without form during the first three days, and
afterwards, on the fourth day, received its form.
If, however, we take these days to denote merely sequence in the natural
order, as Augustine holds (Gen. ad lit. iv, 22,24), and not succession in
time, there is then nothing to prevent our saying, whilst holding any one
of the opinions given above, that the substantial formation of the
firmament belongs to the second day.
Another possible explanation is to understand by the firmament that was
made on the second day, not that in which the stars are set, but the part
of the atmosphere where the clouds are collected, and which has received
the name firmament from the firmness and density of the air. "For a body
is called firm," that is dense and solid, "thereby differing from a
mathematical body" as is remarked by Basil (Hom. iii in Hexaem.). If,
then, this explanation is adopted none of these opinions will be found
repugnant to reason. Augustine, in fact (Gen. ad lit. ii, 4), recommends
it thus: "I consider this view of the question worthy of all
commendation, as neither contrary to faith nor difficult to be proved and
Reply to Objection 1: According to Chrysostom (Hom. iii in Genes.), Moses
prefaces his record by speaking of the works of God collectively, in the
words, "In the beginning God created heaven and earth," and then proceeds
to explain them part by part; in somewhat the same way as one might say:
"This house was constructed by that builder," and then add: "First, he
laid the foundations, then built the walls, and thirdly, put on the
roof." In accepting this explanation we are, therefore, not bound to hold
that a different heaven is spoken of in the words: "In the beginning God
created heaven and earth," and when we read that the firmament was made
on the second day.
We may also say that the heaven recorded as created in the beginning is
not the same as that made on the second day; and there are several senses
in which this may be understood. Augustine says (Gen. ad lit. i, 9) that
the heaven recorded as made on the first day is the formless spiritual
nature, and that the heaven of the second day is the corporeal heaven.
According to Bede (Hexaem. i) and Strabus, the heaven made on the first
day is the empyrean, and the firmament made on the second day, the starry
heaven. According to Damascene (De Fide Orth. ii) that of the first day
was spherical in form and without stars, the same, in fact, that the
philosophers speak of, calling it the ninth sphere, and the primary
movable body that moves with diurnal movement: while by the firmament
made on the second day he understands the starry heaven. According to
another theory, touched upon by Augustine [*Gen. ad lit. ii, 1] the
heaven made on the first day was the starry heaven, and the firmament
made on the second day was that region of the air where the clouds are
collected, which is also called heaven, but equivocally. And to show that
the word is here used in an equivocal sense, it is expressly said that
"God called the firmament heaven"; just as in a preceding verse it said
that "God called the light day" (since the word "day" is also used to
denote a space of twenty-four hours). Other instances of a similar use
occur, as pointed out by Rabbi Moses.
The second and third objections are sufficiently answered by what has
been already said.
Article 2: Whether there are waters above the firmament?
Objection 1: It would seem that there are not waters above the firmament. For water is heavy by nature, and heavy things tend naturally downwards, not upwards. Therefore there are not waters above the firmament.
Objection 2: Further, water is fluid by nature, and fluids cannot rest on a
sphere, as experience shows. Therefore, since the firmament is a sphere,
there cannot be water above it.
Objection 3: Further, water is an element, and appointed to the generation of
composite bodies, according to the relation in which imperfect things
stand towards perfect. But bodies of composite nature have their place
upon the earth, and not above the firmament, so that water would be
useless there. But none of God's works are useless. Therefore there are
not waters above the firmament.
On the contrary, It is written (Gn. 1:7): "(God) divided the waters that
were under the firmament, from those that were above the firmament."
I answer with Augustine (Gen. ad lit. ii, 5) that, "These words of
Scripture have more authority than the most exalted human intellect.
Hence, whatever these waters are, and whatever their mode of existence,
we cannot for a moment doubt that they are there." As to the nature of
these waters, all are not agreed. Origen says (Hom. i in Gen.) that the
waters that are above the firmament are "spiritual substances." Wherefore
it is written (Ps. 148:4): "Let the waters that are above the heavens
praise the name of the Lord," and (Dn. 3:60): "Ye waters that are above
the heavens, bless the Lord."To this Basil answers (Hom. iii in Hexaem.)
that these words do not mean that these waters are rational creatures,
but that "the thoughtful contemplation of them by those who understand
fulfils the glory of the Creator." Hence in the same context, fire, hail,
and other like creatures, are invoked in the same way, though no one
would attribute reason to these.
We must hold, then, these waters to be material, but their exact nature
will be differently defined according as opinions on the firmament
differ. For if by the firmament we understand the starry heaven, and as
being of the nature of the four elements, for the same reason it may be
believed that the waters above the heaven are of the same nature as the
elemental waters. But if by the firmament we understand the starry
heaven, not, however, as being of the nature of the four elements then
the waters above the firmament will not be of the same nature as the
elemental waters, but just as, according to Strabus, one heaven is called
empyrean, that is, fiery, solely on account of its splendor: so this
other heaven will be called aqueous solely on account of its
transparence; and this heaven is above the starry heaven. Again, if the
firmament is held to be of other nature than the elements, it may still
be said to divide the waters, if we understand by water not the element
but formless matter. Augustine, in fact, says (Super Gen. cont. Manich.
i, 5,7) that whatever divides bodies from bodies can be said to divide
waters from waters.
If, however, we understand by the firmament that part of the air in
which the clouds are collected, then the waters above the firmament must
rather be the vapors resolved from the waters which are raised above a
part of the atmosphere, and from which the rain falls. But to say, as
some writers alluded to by Augustine (Gen. ad lit. ii, 4), that waters
resolved into vapor may be lifted above the starry heaven, is a mere
absurdity. The solid nature of the firmament, the intervening region of
fire, wherein all vapor must be consumed, the tendency in light and
rarefied bodies to drift to one spot beneath the vault of the moon, as
well as the fact that vapors are perceived not to rise even to the tops
of the higher mountains, all to go to show the impossibility of this. Nor
is it less absurd to say, in support of this opinion, that bodies may be
rarefied infinitely, since natural bodies cannot be infinitely rarefied
or divided, but up to a certain point only.
Reply to Objection 1: Some have attempted to solve this difficulty by supposing
that in spite of the natural gravity of water, it is kept in its place
above the firmament by the Divine power. Augustine (Gen. ad lit. ii, 1),
however will not admit this solution, but says "It is our business here
to inquire how God has constituted the natures of His creatures, not how
far it may have pleased Him to work on them by way of miracle." We leave
this view, then, and answer that according to the last two opinions on
the firmament and the waters the solution appears from what has been
said. According to the first opinion, an order of the elements must be
supposed different from that given by Aristotle, that is to say, that the
waters surrounding the earth are of a dense consistency, and those around
the firmament of a rarer consistency, in proportion to the respective
density of the earth and of the heaven.
Or by the water, as stated, we may understand the matter of bodies to be
Reply to Objection 2: The solution is clear from what has been said, according to
the last two opinions. But according to the first opinion, Basil gives
two replies (Hom. iii in Hexaem.). He answers first, that a body seen as
concave beneath need not necessarily be rounded, or convex, above.
Secondly, that the waters above the firmament are not fluid, but exist
outside it in a solid state, as a mass of ice, and that this is the
crystalline heaven of some writers.
Reply to Objection 3: According to the third opinion given, the waters above the
firmament have been raised in the form of vapors, and serve to give rain
to the earth. But according to the second opinion, they are above the
heaven that is wholly transparent and starless. This, according to some,
is the primary mobile, the cause of the daily revolution of the entire
heaven, whereby the continuance of generation is secured. In the same way
the starry heaven, by the zodiacal movement, is the cause whereby
different bodies are generated or corrupted, through the rising and
setting of the stars, and their various influences. But according to the
first opinion these waters are set there to temper the heat of the
celestial bodies, as Basil supposes (Hom. iii in Hexaem.). And Augustine
says (Gen. ad lit. ii, 5) that some have considered this to be proved by
the extreme cold of Saturn owing to its nearness to the waters that are
above the firmament.
Article 3: Whether the firmament divides waters from waters?
Objection 1: It would seem that the firmament does not divide waters from
waters. For bodies that are of one and the same species have naturally
one and the same place. But the Philosopher says (Topic. i, 6): "All
water is the same species." Water therefore cannot be distinct from water
Objection 2: Further, should it be said that the waters above the firmament
differ in species from those under the firmament, it may be argued, on
the contrary, that things distinct in species need nothing else to
distinguish them. If then, these waters differ in species, it is not the
firmament that distinguishes them.
Objection 3: Further, it would appear that what distinguishes waters from
waters must be something which is in contact with them on either side, as
a wall standing in the midst of a river. But it is evident that the
waters below do not reach up to the firmament. Therefore the firmament
does not divide the waters from the waters.
On the contrary, It is written (Gn. 1:6): "Let there be a firmament made
amidst the waters; and let it divide the waters from the waters."
I answer that, The text of Genesis, considered superficially, might lead
to the adoption of a theory similar to that held by certain philosophers
of antiquity, who taught that water was a body infinite in dimension, and
the primary element of all bodies. Thus in the words, "Darkness was upon
the face of the deep," the word "deep" might be taken to mean the
infinite mass of water, understood as the principle of all other bodies.
These philosophers also taught that not all corporeal things are confined
beneath the heaven perceived by our senses, but that a body of water,
infinite in extent, exists above that heaven. On this view the firmament
of heaven might be said to divide the waters without from those
within---that is to say, from all bodies under the heaven, since they
took water to be the principle of them all.
As, however, this theory can be shown to be false by solid reasons, it
cannot be held to be the sense of Holy Scripture. It should rather be
considered that Moses was speaking to ignorant people, and that out of
condescension to their weakness he put before them only such things as
are apparent to sense. Now even the most uneducated can perceive by their
senses that earth and water are corporeal, whereas it is not evident to
all that air also is corporeal, for there have even been philosophers who
said that air is nothing, and called a space filled with air a vacuum.
Moses, then, while he expressly mentions water and earth, makes no
express mention of air by name, to avoid setting before ignorant persons
something beyond their knowledge. In order, however, to express the truth
to those capable of understanding it, he implies in the words: "Darkness
was upon the face of the deep," the existence of air as attendant, so to
say, upon the water. For it may be understood from these words that over
the face of the water a transparent body was extended, the subject of
light and darkness, which, in fact, is the air.
Whether, then, we understand by the firmament the starry heaven, or the
cloudy region of the air, it is true to say that it divides the waters
from the waters, according as we take water to denote formless matter, or
any kind of transparent body, as fittingly designated under the name of
waters. For the starry heaven divides the lower transparent bodies from
the higher, and the cloudy region divides that higher part of the air,
where the rain and similar things are generated, from the lower part,
which is connected with the water and included under that name.
Reply to Objection 1: If by the firmament is understood the starry heaven, the
waters above are not of the same species as those beneath. But if by the
firmament is understood the cloudy region of the air, both these waters
are of the same species, and two places are assigned to them, though not
for the same purpose, the higher being the place of their begetting, the
lower, the place of their repose.
Reply to Objection 2: If the waters are held to differ in species, the firmament
cannot be said to divide the waters, as the cause of their destruction,
but only as the boundary of each.
Reply to Objection 3: On account of the air and other similar bodies being
invisible, Moses includes all such bodies under the name of water, and
thus it is evident that waters are found on each side of the firmament,
whatever be the sense in which the word is used.
Article 4: Whether there is only one heaven?
Objection 1: It would seem that there is only one heaven. For the heaven is
contrasted with the earth, in the words, "In the beginning God created
heaven and earth."But there is only one earth. Therefore there is only
Objection 2: Further, that which consists of the entire sum of its own matter,
must be one; and such is the heaven, as the Philosopher proves (De Coel.
i, text. 95). Therefore there is but one heaven.
Objection 3: Further, whatever is predicated of many things univocally is
predicated of them according to some common notion. But if there are more
heavens than one, they are so called univocally, for if equivocally only,
they could not properly be called many. If, then, they are many, there
must be some common notion by reason of which each is called heaven, but
this common notion cannot be assigned. Therefore there cannot be more
than one heaven.
On the contrary, It is said (Ps. 148:4): "Praise Him, ye heavens of
I answer that, On this point there seems to be a diversity of opinion
between Basil and Chrysostom. The latter says that there is only one
heaven (Hom. iv in Gen.), and that the words 'heavens of heavens' are
merely the translation of the Hebrew idiom according to which the word is
always used in the plural, just as in Latin there are many nouns that are
wanting in the singular. On the other hand, Basil (Hom. iii in Hexaem.),
whom Damascene follows (De Fide Orth. ii), says that there are many
heavens. The difference, however, is more nominal than real. For
Chrysostom means by the one heaven the whole body that is above the earth
and the water, for which reason the birds that fly in the air are called
birds of heaven [*Ps. 8:9]. But since in this body there are many
distinct parts, Basil said that there are more heavens than one.
In order, then, to understand the distinction of heavens, it must be
borne in mind that Scripture speaks of heaven in a threefold sense.
Sometimes it uses the word in its proper and natural meaning, when it
denotes that body on high which is luminous actually or potentially, and
incorruptible by nature. In this body there are three heavens; the first
is the empyrean, which is wholly luminous; the second is the aqueous or
crystalline, wholly transparent; and the third is called the starry
heaven, in part transparent, and in part actually luminous, and divided
into eight spheres. One of these is the sphere of the fixed stars; the
other seven, which may be called the seven heavens, are the spheres of
In the second place, the name heaven is applied to a body that
participates in any property of the heavenly body, as sublimity and
luminosity, actual or potential. Thus Damascene (De Fide Orth. ii) holds
as one heaven all the space between the waters and the moon's orb,
calling it the aerial. According to him, then, there are three heavens,
the aerial, the starry, and one higher than both these, of which the
Apostle is understood to speak when he says of himself that he was "rapt
to the third heaven."
But since this space contains two elements, namely, fire and air, and in
each of these there is what is called a higher and a lower region Rabanus
subdivides this space into four distinct heavens. The higher region of
fire he calls the fiery heaven; the lower, the Olympian heaven from a
lofty mountain of that name: the higher region of air he calls, from its
brightness, the ethereal heaven; the lower, the aerial. When, therefore,
these four heavens are added to the three enumerated above, there are
seven corporeal heavens in all, in the opinion of Rabanus.
Thirdly, there are metaphorical uses of the word heaven, as when this
name is applied to the Blessed Trinity, Who is the Light and the Most
High Spirit. It is explained by some, as thus applied, in the words, "I
will ascend into heaven"; whereby the evil spirit is represented as
seeking to make himself equal with God. Sometimes also spiritual
blessings, the recompense of the Saints, from being the highest of all
good gifts, are signified by the word heaven, and, in fact, are so
signified, according to Augustine (De Serm. Dom. in Monte), in the words,
"Your reward is very great in heaven" (Mt. 5:12).
Again, three kinds of supernatural visions, bodily, imaginative, and
intellectual, are called sometimes so many heavens, in reference to which
Augustine (Gen. ad lit. xii) expounds Paul's rapture "to the third
Reply to Objection 1: The earth stands in relation to the heaven as the centre of
a circle to its circumference. But as one center may have many
circumferences, so, though there is but one earth, there may be many
Reply to Objection 2: The argument holds good as to the heaven, in so far as it
denotes the entire sum of corporeal creation, for in that sense it is one.
Reply to Objection 3: All the heavens have in common sublimity and some degree of
luminosity, as appears from what has been said.