Theme 1A: Inductive arguments: Cosmological
The Concept of A Posteriori
T he cosmological and teleological arguments are botha posterioriproofs. This means they
arrive at their conclusions after evaluatingempiricaldata— observation of the world and the
phenomena within it.
Inductive arguments:
● egin with experience.
B
● Move from observation to a general conclusion.
● Offer atprobablerather than a certain conclusion.
● Can be valid and sound, yet still not give an indisputable conclusion.
n inductive argument gives a conclusion that is one ofseveral possibilities. Cosmological
A
arguments suggest God as the best explanation, but not a logically unavoidable one.
Cosmological Argument: Aquinas’ First Three Ways
quinas’ Five Ways (fromSumma Theologica) are logicalarguments for God’s existence. The
A
first three are cosmological and draw heavily on Aristotle’s philosophy. They are a posteriori
because they begin with observation of the world.
They attempt to show:
● T he universe requires a first principle.
● Infinite regressis impossible.
● Therefore, there must be a first cause or necessary being.
● This is identified as God.
Key Aristotelian Concepts
otion (Change)
M
For Aquinas, motion does not simply mean physical movement. It refers to change from
potentialitytoactuality.
A
● ctuality: an item’s present state.
● Potentiality: a possible future state.
In Aquinas’ example, wood is potentially hot but actually cold. Fire, which is actually hot, makes
the wood actually hot. Nothing can move from potentiality to actuality unless something
,a lready actual causes the change. A thing cannot be both potential and actual in the same
respect at the same time, and therefore cannot move itself.
The First Way – Motion
quinas observes that things in the world arein motion(i.e., change). Whatever is in motion
A
must be moved by something else.Nothing can moveitself, because it would have to be prior
to itself, which is impossible.
T he chain of movers cannot regress infinitely. If there were no first mover, there would be no
subsequent movement at all. Therefore, there must be aFirst Mover, itself unmoved.
There must be:
● first mover.
A
● A being not moved by anything else.
● A source of all motion.
● This unmoved mover is what“all men call God.”
Importantly, Aquinas is not describing an infinite series stretching backwards in time. He is
describing ahierarchical series operating here andnow.Without a first sustaining cause,
nothing would be moving at all.
The Second Way – Efficient Cause
T he Second Way focuses oncause and effect, specificallyefficientcausation — the cause that
brings something into existence.
F or example, a sculptor is the efficient cause of a statue. Nothing can be the efficient cause of
itself, because it would have to exist before itself, which is impossible.
e observe anordered series of efficient causes.This seriescannot regress infinitely, because
W
without a first cause, there would be no intermediate or ultimate causes. Removing the first
cause removes the entire chain (as illustrated by the domino analogy).
There must be:
● first efficient cause.
A
● A cause that is itself uncaused.
● A source of all other causes.
● This first cause is called God.
, t this stage, the argument establishes only an uncaused cause — not yet the full God of
A
classical theism.
The Third Way – Contingency and Necessity
T he Third Way concernsexistenceitself.“We findin nature things that are possible to be and
not to be”— theycome into existenceand pass away.A contingent being:
D
● ependson something else for its existence.
● Can begin and cease to exist.
● Has the possibility of not existing.
quinas argues that if everything were contingent, then at some time nothing would have
A
existed. If at some time nothing existed, nothing could begin to exist. Yet things clearly do exist
now. Therefore,not everything can be contingent.
There must be:
● necessary being.
A
● A being whose existence isnot dependent on anythingelse.
● A being that has its own necessity.
● The source of existence for contingent beings.
● This necessary being is God.
Unlike contingent beings, a necessary beingcannotfail to exist.
The Kalam Cosmological Argument – William Lane Craig
T he Kalam argument has roots in Islamic philosophy (9th–11th centuries) and was modernised
by William Lane Craig. It is also cosmological but focuses specifically on thebeginning of the
universe.
Basic Structure
. E verything thatbegins to existhas a cause.
1
2. The universe began to exist.
3. Therefore, the universe has a cause (which Craig argues is personal).
, Part One: The Universe Began to Exist
Craig argues that the universecannot be infinitein the past.
nactual infiniteis a completed, boundless set.Craig argues that actual infinities cannot exist
A
in reality because they producelogical absurdities(illustrated by examples such as an infinite
library of red and black books).
beginningless temporal series would be an actual infinite. Therefore,a beginningless universe
A
cannot exist.
raig also argues that the present moment has been reached by thesuccessive additionof
C
events. A collection formed by successive addition cannot be actually infinite. Since we have
reached the present,the past must be finite. Therefore,the universe began to exist.
Part Two: The Cause Must Be Personal
If the universe began to exist, it must have a cause. That causecannot be the laws of nature,
since they began with the universe. Craig argues that if the cause were an eternal mechanical
set of conditions, the effect would also be eternal. However, the universe began at a specific
point in time. Therefore, the cause must be capable of choosing to create.
There must be:
● cause outside space and time.
A
● A causenot governed by physical laws.
● A being capable of deliberate action.
● A personal agent with awill.
● This is apersonal Creator.
raig concludes that the cause of the universe shares key attributes of the theistic God:
C
transcendence, power, and agency.
The Concept of A Posteriori
T he cosmological and teleological arguments are botha posterioriproofs. This means they
arrive at their conclusions after evaluatingempiricaldata— observation of the world and the
phenomena within it.
Inductive arguments:
● egin with experience.
B
● Move from observation to a general conclusion.
● Offer atprobablerather than a certain conclusion.
● Can be valid and sound, yet still not give an indisputable conclusion.
n inductive argument gives a conclusion that is one ofseveral possibilities. Cosmological
A
arguments suggest God as the best explanation, but not a logically unavoidable one.
Cosmological Argument: Aquinas’ First Three Ways
quinas’ Five Ways (fromSumma Theologica) are logicalarguments for God’s existence. The
A
first three are cosmological and draw heavily on Aristotle’s philosophy. They are a posteriori
because they begin with observation of the world.
They attempt to show:
● T he universe requires a first principle.
● Infinite regressis impossible.
● Therefore, there must be a first cause or necessary being.
● This is identified as God.
Key Aristotelian Concepts
otion (Change)
M
For Aquinas, motion does not simply mean physical movement. It refers to change from
potentialitytoactuality.
A
● ctuality: an item’s present state.
● Potentiality: a possible future state.
In Aquinas’ example, wood is potentially hot but actually cold. Fire, which is actually hot, makes
the wood actually hot. Nothing can move from potentiality to actuality unless something
,a lready actual causes the change. A thing cannot be both potential and actual in the same
respect at the same time, and therefore cannot move itself.
The First Way – Motion
quinas observes that things in the world arein motion(i.e., change). Whatever is in motion
A
must be moved by something else.Nothing can moveitself, because it would have to be prior
to itself, which is impossible.
T he chain of movers cannot regress infinitely. If there were no first mover, there would be no
subsequent movement at all. Therefore, there must be aFirst Mover, itself unmoved.
There must be:
● first mover.
A
● A being not moved by anything else.
● A source of all motion.
● This unmoved mover is what“all men call God.”
Importantly, Aquinas is not describing an infinite series stretching backwards in time. He is
describing ahierarchical series operating here andnow.Without a first sustaining cause,
nothing would be moving at all.
The Second Way – Efficient Cause
T he Second Way focuses oncause and effect, specificallyefficientcausation — the cause that
brings something into existence.
F or example, a sculptor is the efficient cause of a statue. Nothing can be the efficient cause of
itself, because it would have to exist before itself, which is impossible.
e observe anordered series of efficient causes.This seriescannot regress infinitely, because
W
without a first cause, there would be no intermediate or ultimate causes. Removing the first
cause removes the entire chain (as illustrated by the domino analogy).
There must be:
● first efficient cause.
A
● A cause that is itself uncaused.
● A source of all other causes.
● This first cause is called God.
, t this stage, the argument establishes only an uncaused cause — not yet the full God of
A
classical theism.
The Third Way – Contingency and Necessity
T he Third Way concernsexistenceitself.“We findin nature things that are possible to be and
not to be”— theycome into existenceand pass away.A contingent being:
D
● ependson something else for its existence.
● Can begin and cease to exist.
● Has the possibility of not existing.
quinas argues that if everything were contingent, then at some time nothing would have
A
existed. If at some time nothing existed, nothing could begin to exist. Yet things clearly do exist
now. Therefore,not everything can be contingent.
There must be:
● necessary being.
A
● A being whose existence isnot dependent on anythingelse.
● A being that has its own necessity.
● The source of existence for contingent beings.
● This necessary being is God.
Unlike contingent beings, a necessary beingcannotfail to exist.
The Kalam Cosmological Argument – William Lane Craig
T he Kalam argument has roots in Islamic philosophy (9th–11th centuries) and was modernised
by William Lane Craig. It is also cosmological but focuses specifically on thebeginning of the
universe.
Basic Structure
. E verything thatbegins to existhas a cause.
1
2. The universe began to exist.
3. Therefore, the universe has a cause (which Craig argues is personal).
, Part One: The Universe Began to Exist
Craig argues that the universecannot be infinitein the past.
nactual infiniteis a completed, boundless set.Craig argues that actual infinities cannot exist
A
in reality because they producelogical absurdities(illustrated by examples such as an infinite
library of red and black books).
beginningless temporal series would be an actual infinite. Therefore,a beginningless universe
A
cannot exist.
raig also argues that the present moment has been reached by thesuccessive additionof
C
events. A collection formed by successive addition cannot be actually infinite. Since we have
reached the present,the past must be finite. Therefore,the universe began to exist.
Part Two: The Cause Must Be Personal
If the universe began to exist, it must have a cause. That causecannot be the laws of nature,
since they began with the universe. Craig argues that if the cause were an eternal mechanical
set of conditions, the effect would also be eternal. However, the universe began at a specific
point in time. Therefore, the cause must be capable of choosing to create.
There must be:
● cause outside space and time.
A
● A causenot governed by physical laws.
● A being capable of deliberate action.
● A personal agent with awill.
● This is apersonal Creator.
raig concludes that the cause of the universe shares key attributes of the theistic God:
C
transcendence, power, and agency.
