Transcript Aquinas-God-107 - People at Creighton University

Aquinas’s arguments for the existence of God
Aquinas’s famous 5 argument appear in both
the Summa Theologica & the Summa Contra
Gentiles
Will examine arguments 2 & 5 only
Aquinas’s approach in all of the arguments
God’s existence can be known through
God’s effects, i.e, the created world
(chapter 12)
Aquinas's 2nd & 5th arguments for God - 1
Aquinas’s arguments for the existence of God
The 2nd argument
1. We experience causality.
2. Nothing is the cause of itself;
causes are other than their effects.
3. There cannot be an infinite regress
of caused causes.
– If there were an infinite regress,
the effects we experience here &
now would not exist.
Aquinas's 2nd & 5th arguments for God - 2
Aquinas’s arguments for the existence of God
The 2nd argument (cont’d)
4. Therefore, there must be some first
cause and this we call “God.”
Critique
Clarification: a temporal series of
causes vs a dependent series. Aquinas is
talking about a dependent series.
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Aquinas’s arguments for the existence of God
Can’t we take the observed causality in
the world as a brute fact which requires
no explanation?
Possible response: If we accept the
Principle of Sufficient Reason, then
causality must have an explanation.
• Why should we accept the P. of SR?
• Because it is a necessary condition for
rationality?
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Aquinas’s arguments for the existence of God
Richard Swinburne (The Existence of
God, 2nd ed. rev., Oxford UP, 1991)
proposes redoing Aquinas’s 2nd argument
• God is necessary to account for the
existence of & the sustaining of the
laws of nature which in turn govern
the causality we experience.
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Aquinas’s arguments for the existence of God
– God
– laws
– causal events
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Aquinas’s arguments for the existence of God
The 5th argument
1. The experiential datum: things which
lack knowledge act toward ends (goals).
• Nature displays goal-directedness; it
is purpose-filled.
2. Things which move toward ends must be
guided by an intelligence.
• Analogy to an arrow shot by an
archer.
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Aquinas’s arguments for the existence of God
The 5th argument (cont’d)
3. Therefore, there must exist an
intelligent being who directs all noncognitive natural things toward their goals.
“And this we call God.”
In the 19th cenutury, William Paley (17431805) in his Natural Theology; or Evidences
of the Existence and Attributes of the Deity
(1802), redid Aquinas’s argument.
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Aquinas’s arguments for the existence of God
Analogy between a clock and the clock-like
design and behavior of the universe as a
whole and especially living things.
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Aquinas’s arguments for the existence of God
Critique of the design argument
The challenge of Darwin’s theory to all
design arguments based on the design of
living things
The theory of natural selection
• (1) Overproduction of pollen, seeds,
eggs, & sperm; yet populations remain
relatively constant.
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Aquinas’s arguments for the existence of God
• (2) There is a high mortality
• (3) Individuals within a species are
not identical; there are some
variations.
• (4) Some of these variations are
inheritable.
• (5) Some individuals are better
adapted than others to the conditions
of life and to ecological niches.
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Aquinas’s arguments for the existence of God
• (6) Because of (5), there is natural
selection & differential survival.
• (7) Over the long run, (6) results in
the rise of divergent stocks issuing
from common ancestors.
Darwin’s theory offers a natural
explanation for the design of living
things. Hence there is no need to appeal
to God for this design.
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Aquinas’s arguments for the existence of God
Responses:
• Can reconcile God with the natural
evolution of the design of living things
by stating that God uses evolution to
bring about this design.
– But note that this is not an
argument for God’s existence; it is
a statement of the compatibility of
God the designer and evolution.
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Aquinas’s arguments for the existence of God
Responses (cont’d)
• Swinburne: God is required to explain
the existence and sustaining of the
laws governing the evolutionary
process.
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Aquinas’s arguments for the existence of God
• Darwin’s theory is restricted to the
realm of life. Some claim we need
God to explain the evolution of the
cosmos from the Big Bang.
– The cosmos displays remarkable
fine-tuning directed toward the
creation of life and mind.
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Aquinas’s arguments for the existence of God
– Illustrations of this fine-tuning
– The expansion rate. Stephen
Hawkings: “If the rate of
expansion one second after the Big
Bang had been smaller by one part
in a hundred thousand million
million it would have recollapsed
before it reached its present size”
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Aquinas’s arguments for the existence of God
– The formation of the elements. If
the strong nuclear force were
slightly weaker we would have only
hydrogen in the universe. If the
force were slightly stronger, all
the hydrogen would have been
converted to helium. In either
case, stars and compounds such as
water could not have formed.
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Aquinas’s arguments for the existence of God
– If the nuclear force had been
slightly stronger, carbon would all
have been converted into oxygen.
– Conclusion: This fine-tuning of the
evolution of the universe can only
be explained by the existence of an
intelligent designer.
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