We discuss that Ontological Argument for God's existence as expressed by St Anselm. Further, we consider another metaphysical argument from St Thomas Aquinas which not only proves that there is a God, but also that there can be only one true God.
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High School Youth Group – Fall 2020 – The Catholic
Response to Atheism
November 22nd - Session 5 – That Than Which Nothing Greater
Can Be Though
“The fool hath said in his heart: There is no
God.” -Psalm 13:1
I. Calendar: November 29th,
No Class, Thanksgiving break; December 20th, Last Class of Fall,
resuming January 10th and continuing until May 2nd.
II. The Ontological Argument of St Anselm
A. “[Even a] fool, when he hears
of … a being than which nothing greater can be conceived … understands what he
hears, and what he understands is in his understanding.… And assuredly that
than which nothing greater can be conceived, cannot exist in the understanding
alone. For suppose it exists in the understanding alone: then it can be
conceived to exist in reality; which is greater.… Therefore, if that than which
nothing greater can be conceived, exists in the understanding alone, the very
being than which nothing greater can be conceived is one than which a greater
can be conceived. But obviously this is impossible. Hence, there is no doubt
that there exists a being than which nothing greater can be conceived, and it
exists both in the understanding and in reality.”
B. Summary of Anselm’s argument:
1. By definition, God is a being
than which none greater can be imagined (that is, the greatest possible being
that can be imagined).
2. God exists as an idea in the
mind.
3. A being that exists as an idea
in the mind and in reality is, other things being equal, greater than a being
that exists only as an idea in the mind.
4. Thus, if God exists only as an
idea in the mind, then we can imagine something that is greater than God (that
is, a greatest possible being that does exist).
5. But we cannot imagine
something that is greater than God (for it is a contradiction to suppose that
we can imagine a being greater than the greatest possible being that can be
imagined.)
6. Therefore, God exists (that is, he exists both as an idea in the
mind and in reality).
III. A metaphysical argument from
St Thomas
1. Among creatures, I can
conceive of their nature/essence as separate from their existence (example: Even as I can imagine a unicorn
that does not exist, I can also conceive of a T-Rex that does not exist)
2. If I can conceive of a
nature/essence of a creature without that creature actually existing, then its
essence is distinct from its existence.
3. For any being in which essence
and existence are distinct, something must cause that essence to actually
exist.
4. But if whatever causes that
creature to exist has an essence distinct from existence then it too is a
creature and must be caused to exist by another.
5. But this cannot go on forever.
6. Therefore, there must be some
first cause whose essence is existence (“I am who am”) and who is the cause of
all other things that exist.
IV. Does the ontological argument
work?
St Thomas, “A thing can be
self-evident in either of two ways: on the one hand, self-evident in itself,
though not to us; on the other, self-evident in itself, and to us. A
proposition is self-evident because the predicate is included in the essence of
the subject, as "Man is an animal," for animal is contained in the
essence of man. If, therefore the essence of the predicate and subject be known
to all, the proposition will be self-evident to all; as is clear with regard to
the first principles of demonstration, the terms of which are common things
that no one is ignorant of, such as being and non-being, whole and part, and
such like. If, however, there are some to whom the essence of the predicate and
subject is unknown, the proposition will be self-evident in itself, but not to
those who do not know the meaning of the predicate and subject of the
proposition. […] Therefore I say that this proposition, "God exists,"
of itself is self-evident, for the predicate is the same as the subject,
because God is His own existence as will be hereafter shown. Now because we do
not know the essence of God, the proposition is not self-evident to us; but
needs to be demonstrated by things that are more known to us, though less known
in their nature — namely, by effects.”
V. How St Thomas’ metaphysical
“thought experiment” proves that there is only one God
Among men, there is both body and
soul. The soul is what makes us to be one (that is, of one nature, all human),
but the body is what makes us to be distinct individuals (and we each have an
individual soul, suited just to this individual body).
Among the angels, they have no body but are pure spirits, only souls.
Therefore, each angelic soul is truly different from every other. Every angel
is his own species! The way that there are various species of animals on earth,
there are many billions and more species of angels! Michael and Gabriel are
both angels – but Michael is truly his own species and Gabriel his own species.
The name “angel” does not describe their nature the way that “human” describes
man’s nature – rather, “angel” tells us the work that they do for God, they are
messengers. Thus, for the angels, what makes them individuals is not a
body, but their souls. What makes them creatures is that they exist.
Now, think of God. In God,
essence is existence – his nature is totally simple and complete. God’s
nature/essence is pure existence. Therefore, there is no distinction possible –
it is impossible that there could be two “Divine Natures” because the essence
of God is pure existence and wholly simple.
Therefore, God is one!
Man = Body + Soul (which is
Essence + Existence). Men have
different bodies to be different men.
Angel = Soul (which is Essence +
Existence). Angels have different
natures to be different angels.
God = Existence. Being pure existence and perfectly simple
without any parts, he can be only one.
