“… if (the best philosophy)

doesn’t seem peculiar you

haven’t understood it”

Edward Craig

1000 BCE 500 BCE 0 500 CE 1000 CE 1500 CE 2000 CE

Scholastics Thomas Aquinas 1225 - 1274

Favoured by RCs Influenced by

Aristotle “Five Ways” or “Five arguments for the existence of God”

a cosmological argument (3 of the 5)

a teleological argument (the 5th)

Thinking based in Christian monasteries

Thomas Aquinas’s “Five Ways”

1. Everything is changing – but something must have caused it.

2. Every effect must have a cause

3. Things come into existence, and cease to exist. There must be a cause.

4. Excellence must come from perfection

5. The harmony of things suggests design. This all must be

God!

The Cosmological Argument

cosmos - the world or universe

based on what can be seen concept of contingency -

dependent on something that may or may not happen

The Cosmological Argument

The Unmoved Mover

Thomas Aquinas’ “First Way” everything that is in motion (changed) is

moved by something else infinite regress is impossible emphasis on dependency “… it is necessary to arrive at a first

mover, moved by no other, and this everyone understands to be God”.

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Example 1• Everything is changed by

something else… • Fire causes something

potentially hot to become actually hot.

• BUT thing which does the changing must itself have been changed by something else.

• MUST stop somewhere (regression !) or there will be no first change !

• First cause of change, itself not changed by anything is GOD…

Some Problems with this argument

• You can’t prove that there is no infinite regression.

• Even if things do go back to a starting point which created everything, it doesn’t have to be in the form of the Christian idea of God. Neitsche said that God is dead.

• The world may have no cause.

• If we are saying that we can’t infinitely regress because we can’t accept infinity, there must be a starting point or a God. But then something must have created God. How can we accept that God is an infinite being if we have just rejected infinity?

• If numbers can go on and on forever then why can’t regression do the same?

The Cosmological Argument

The Uncaused Causer

Thomas Aquinas’ “Second Way” everything that happens has a cause infinite regress is impossible emphasis on agency “There is no case known … in which a

thing is found to be the efficient cause of itself … it is necessary to admit a first efficient cause, to which everyone gives the name of God”

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Example 2• I sit at a computer typing these words….• WHAT is the cause of this action ?• Might trace back muscular movements and

electrical impulses in the brain.• Physical systems related to oxygen, food &

drink…• Chain of causes beyond that have computer on

desk (software & hardware !). Touches many lives I will never know !

• Publisher of books, tradition of reading, buying, studying….

• Gravity to keep me in chair…• Motivation for sitting here and writing !

Criticism : Does Aquinas contradict himself?

• Aquinas says that nothing can be the cause of itself (the Second Way)

• However he then goes on to say something must exist that can be the cause of itself, namely God

• Is the premise contradicted by the conclusion?

Does Aquinas contradict himself?

• YES – It is a logical contradiction and therefore the argument does not make sense.

• NO – There has to be an exception to the rule “everything has a cause” or the universe would have no cause and would not have come to exist.

What does that mean?

Aquinas defends himself against the claim that his argument is illogical by saying that God is an exception because when we talk about God, we are talking about a being unlike anything else. God has a special form of existence that cannot be talked about in terms of logic.

What the critics say next…

• Suppose we do allow that an exception can be made to the rule, “everything must have a cause”.

• Why make God the exception? Why couldn’t the universe be the exception?

What?

The critics are trying to say:• It may be fair to say that

everything that exists within the universe must have a cause

• But why does the universe itself need to have a cause?

• It could be self-causing, or it may not require an explanation at all: it just is.

The Cosmological Argument

Possibility and Necessity Thomas Aquinas’ “Third Way”

things come into being and later cease to exist

some contingent beings exist if any contingent beings exist, then a

necessary being must exist (the cause of the universe must be external to it and must always have existed)

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Problems with this argument:•Even though this argument is logical and is the simplest explanation, there are much deeper things to the argument that need to be considered.•This argument depends on your belief in God.•Why does there have to be a point where nothing existed?•God cannot be the answer, because we don’t know why He/She created the world.There can’t be a reason for everything.

David Hume (1711-1776)

• Hume was an empiricist (he believed all knowledge came from experience)

• He believed in cause and effect because we can see the effects and therefore identify the causes

So, what was Hume’s problem?

• Hume said that this only worked for individual things, not the universe.

• The universe is an unique “effect” and we are unable to experience its cause (we can’t get outside of the universe to see what caused it).

Hume’s second problem• According to Hume, the idea of a

necessary being makes no sense• There is no being the non-existence of

which is inconceivable – and even if there were, why should it be God?

• Why should we say that God, who is unknowable, possesses qualities that make his non-existence a logical impossibility?

Think about this…• Even if the criticisms don’t

manage to disprove God altogether, what do they say about him?

• Remember the Cosmological Argument is about the universe’s existence, not its nature

• Do the criticisms reduce God to merely the first push on the dominoes?

• If so, does that make God worthy of worship?