Arguments based on observation

Most arguments for existence of God are what?

Are examples of a posteriori reasoning

They depend on experience + observation

Are Aquinas’ five ways a posteriori?

Yes → he didn’t believe that a priori arguments for God were valid

This was due to the belief that knowledge comes from sensory experience - Aquinas was deeply influence by Aristotle

Give the 2 examples of a posteriori arguments for existence of God

→ Teleological arguments

→ Cosmological arguments

How do teleological arguments attempt to demonstrate the existence of God?

The evidence of order + purpose in world around us suggests an intelligent designer

Argue that we would not have complex, purposeful features in the world unless there was a divine intelligence

These things cannot just arrive as the result of chance: so, there must be some being, outside the universe which designed the world this way

How do cosmological arguments attempt to demonstrate the existence of God?

→ By asking the question ‘Why is there something rather than nothing?’ → Suggest that everything in existence must have a cause, ultimately leading to the conclusion that there must be an uncaused cause, which is identified as God

How does natural theology attempt to demonstrate the existence of God?

→ Combines reason + observation to infer God's existence from the natural world

→ Natural theology posits that the design + order observable in nature can lead to knowledge of God

How does revealed theology attempt to demonstrate God’s existence? Can NT + RT work together?

→ Asserts that knowledge of God comes through divine revelation, primarily through sacred texts + RE

→ Posits that understanding God is accessible through faith + teachings disclosed to humanity, which can complement the insights of natural theology

→ Can give people truths that reason alone couldn’t work out e.g. life after death/Jesus Christ

For Paul, it was obvious we could learn about God just by looking around us, what are some difficulties/criticisms of this argument?

→ Not everyone sees a world of beauty/order/purpose e.g. might see a world of suffering/hardships - subjective interpretation

→ Some may look for scientific explanations of the workings of the world rather than assuming a divine creator

→ Others believe we can only learn about God when he chooses to reveal truths to us - our powers of reason are limited

Aquinas’ five ways

→ Aquinas was a 13th century monk

→ He wrote his five ways, attempting to demonstrate the existence of God in his book Summa Theologica

How did Aquinas think knowledge of God be reached? 2 ways

→ Revelation - God chooses to reveal truths

→ Through human reason - he believed we were given reason by God for this very purpose

Aquinas thought that the existence of God wasn’t self-evident, but could be demonstrated with logical thought

Evaluate

If something is not self-evident and not directly observable, why should we presume it exists at all?

Why go looking for God instead of simply accepting that reality exists without ultimate explanation?

The Teleological Argument: Aquinas’ Fifth Way

→ Uses the observation that non-intelligent organic life acts in certain, ordered, cyclical + purposive ways - e.g. given the right conditions, acorns always grow into oak trees, the river can’t decide to flow out to the sea as it has no mind, yet it does

→ The fact that non-intelligent things always act in certain ways for certain goals implies that they were given those goals by intelligence as only intelligent beings can assign a purpose

Aquinas’ fifth way - archery analogy

→ Gives the example of arrows fired by an archer

→ We know that someone must have aimed + fired them

→ In the same way, we can conclude the guiding hand of God must be behind the purposiveness of inanimate objects

→ So, everything in nature which is moving but doesn’t have intelligence must be directed to its goal by God

Aquinas’ fifth way simplified

• The natural world obeys natural laws (pre-Newtonian physics essentially)

• Natural things flourish as they obey these laws

• Things without intelligence can’t direct themselves

• So, things without intelligence require something with intelligence to direct them to their goals

• This is God

In the eighteenth century, the fields of science were developing at an exciting pace, how did people who wanted to show the existence of God use these scientific progressions to support existence of God?

→ Different plants were suited to different habitats e.g. plants in desert climates had large leaves for water retention

→ Different animals were made in different ways so that they could live in specific environments

→ Physicists were discovering motion, gravity - these rules appeared to work uniformly in all kinds of circumstances - there is an order in the way inanimate objects operate

→ Invention of microscope - intricate structure + function of cells

The more that people discovered, the clearer it seemed that there was an intelligent creator behind it all

Paley’s design argument

→ If someone found a rock on the ground, they wouldn’t ask how the rock got there - they would assume natural causes

→ But if someone found a watch, how well the watch worked in order to tell the time - must have a designer

→ This is due to the complexity + inherent purpose of the watch - it has been put together in a complex manner to tell the time

→ The universe is much more complex + ordered so the universe must have a designer

More from Paley

→ Everything is clearly designed, for a purpose, to an infinite degree of care

→ Even on smallest scale, there is evidence of craft + skill

→ The same care seems to have been taken with each design

→ This is not only evidence of intelligent design, but of God’s care

→ This must point to an intelligent designer, not by chance - must be God

Strengths of Aquinas’ fifth way

→ There are examples in nature of non-thinking beings that act to achieve a purpose: a sunflower always turns to face the sunlight

→ The arrow analogy is correct + valid. So we can argue it seems reasonable to assume natural things are also directed towards their purpose (CA: can we really compare an arrow + a sunflower?)

→ Is right that we need an explanation for purpose. It is a sign of a conscious mind that plans an end within its design. God is an explanation that works

Counter arguments to Aquinas’ fifth way

→ Assumes all things need a designer to conclude that God designed everything - ‘begs the question’

→ Makes an assumption about purpose. This ‘purpose’ could be due to chance, or perhaps natural things don’t have an innate purpose - may be a human construct

→ Logical fallacy - makes a logical leap to the idea of God of classical theism. Even if we assume a designer, no reason to assume characteristics of this God (e.g. omnibenevolent)

→ Natural selection/evolution is an alternate explanation for apparent purpose. Living beings + organisms look purposeful, but it’s because they have evolved to suit their environment. So, looks like design but has occurred as a result of survival of fittest

Strengths of Paley’s design argument

→ Clear + relatable analogy: watch analogy makes the argument easy to understand; complexity + order in nature intuitively suggest a designer (attractive argument)

→ Points to an intelligent, purposeful God: suggests not just a creator but a wise + intentional designer, fitting with the God of classical theism (suggests intentionality + skill)

→ Compatible with Modern Science: ongoing discoveries (e.g. DNA complexity) can still support the idea of design, making the argument relevant today

Counter arguments to Paley’s design argument

→ Weak analogy
We know watches are designed — unfair to compare to the universe, which is unfamiliar and unique.

→ Multiple designers?
Watches have many makers — why assume one God designed the universe?

→ Assuming simplicity
A rock seems simple, but its formation (e.g., sedimentation) is complex — not clear where design starts/stops.

→ Hume: Limited conclusion
Argument only shows a designer, not an all-powerful, all-good God.

→ Problem of evil
Natural suffering (e.g., Dawkins’ digger wasp) challenges idea of a benevolent designer.

→ Subjective complexity
What counts as “complex” is subjective — not everyone sees design.

The cosmological argument

→ Also comes from NT

→ Starting point of argument is the universe - looks for a reason why the universe should exist

→ Presence of the cosmos as evidence for God instead of design

→ Asks: Why is there something instead of nothing?

→ Basis of argument is that the universe account for its own existence

Three of Aquinas’ five ways

The classic formulations of the cosmological argument can be found in the first three of Aquinas’ five ways

They have their roots in Aristotelian philosophy → unmoved mover

What two assumptions does Aquinas base his argument on?

1. The universe exists

2. There must be a reason why

What is a counter to assumption 2?

→ Some people e.g. Russell/Dawkins are happy to accept that the universe just is, without moving to the conclusion that there should be some reason for it

But Aquinas took the view that there must be an explanation to why anything exists at all

Aquinas’ first way - the unmoved mover

→ Concentrates on change/motion in the world

→ Everything which is in motion/changing has to be put into motion or changed by something else

→ However, there can’t be an infinite sequence of one thing moving another

→ So there must have been an unmoved mover to set the whole thing off = God

‘Nothing can be reduced from potentiality to actuality, except by something in a state of actuality’

What was Aquinas trying to show with his first way?

Wanted to emphasise dependency → rather than going back in time until a beginning

He was using the idea that God sustains the universe - we wouldn’t have change/motion without a first mover

Aquinas’ second way - the uncaused causer

→ All things are caused by other things - every effect has a cause

→ Nothing can be the cause of itself

→ Infinite regress is impossible - otherwise there would be nothing now (no initial cause means there couldn’t be other causes)

→ So, there must be a first cause, itself uncaused, which began the causes

→ This is God

Aquinas took up Aristotle’s understanding of causes → must be a first efficient cause = God

Contingent

Depending on other things

Necessary existence

Existence which doesn’t depend on anything else

Aquinas’ third way - argument from contingency

→ The world consists of contingent beings - dependent on something else for their existence

→ There can't only be contingent things because that would mean that there's an infinite regress of contingency, + a possibility that nothing might have existed

→ An infinite regress is impossible

→ There must be something that is necessary (impossible not to exist)

→ There must be an uncaused necessary being = God, who sets off contingency but isn’t part of the contingency

(Modern understanding of eco-systems + food chains further support Aquinas)

Leibniz’s principle of sufficient reason

‘Why is there something rather than nothing?’ ‘Why does anything exist at all?’

• If something exists, there must be a reason as to why it exists

• If something is true, there must be a reason as to why it is true

• If something happens, there must be a reason as to why that thing happens

How is Leibniz’s principle of sufficient reason useful for the existence of God

Shows the universe needs an ultimate explanation — this is a necessary being (God), whose existence is explained by its own nature

CA: Universe might just be a ‘brute fact’ - simply exists without needing a further explanation - Russell

Positives of Aquinas’ cosmological argument

→ Logical + intuitive: we can observe motion + change in universe, we can observe cause + effect

→ Supports idea of a necessary being: explains why anything exists rather than nothing

→ Compatible with scientific evidence: Big bang suggests universe had a beginning - supports idea of a first cause

Negatives of Aquinas’ cosmological argument

→ Fallacy of composition: Just because things within the universe have causes, it doesn't mean the universe as a whole needs one (Hume)

→ Possibility of infinite regress: Some philosophers argue an infinite chain of causes is possible + doesn’t require a first cause

→ Doesn’t prove God of classical theism: Even if there is a necessary being, it doesn’t have to be the omnibenevolent, omnipotent, omniscient God of Christianity — it could be something impersonal

→ Perhaps our understanding of cause + effect is more like a correlation than a cause; they may occur together, but we can’t be sure one caused the other

Hume’s criticism 1 of arguments for the existence of God

The analogy between a watch + the world is weak

→ Characteristics of purpose + design might be obvious in a watch, but not so obvious in world

→ A watch cannot have come about naturally - conclude that it is designed as no design as such is seen in nature

→ It is not right to compare the world to a machine - there is little similarity

Hume’s criticism 2 of arguments for the existence of God

Order in the world doesn’t necessarily mean that someone must have had the idea of the design

→ Logical fallacy, there is a leap from recognising order in world to the idea of a divine orderer

→ We don’t know if all order comes about due to an intelligent idea/creator

→ Most we can say is that there is order in the world

→ Also limitations to order: no other worlds to compare with ours/no standard, if we could compare maybe our world would seem very unordered

Hume’s criticism 3 of arguments for the existence of God

Order is a necessary part of world’s existence

→ Any world will look designed, because if it were chaotic, it wouldn’t survive

→ Not enough to show that world is orderly for conclusion to be drawn that God must have designed it

→ Alternate explanation = chance/evolution - creatures that survived are suited to purpose due to chance - survival of fittest

Hume’s criticism 4 of arguments for the existence of God

Criticised assumption that if we look at effects (world), we can infer cause (God)

→ Cause + effect doesn’t operate as simply as Aquinas asserted (looking at world around us shows God)

→ Even if we can assume a creator (wasn’t sure that we could) - no reason to suggest that this creator is Christian God

→ We have a finite + imperfect world - no need to assume there must be an infinite + perfect God behind it

→ Cannot make great leaps + assume B follows from A - could be a variety of explanations

What does Hume try + show with example of kitchen scales? Ties into his 5th criticism

We cannot know what caused something when we only have the effect to look at

We cannot infer with any confidence by how much one scale outweighs the other

We couldn’t claim with any authority that it had an infinite weight

Hume’s criticism 5 of arguments for the existence of God

When we look at the world, we only have effect to look at - cause is hidden

We don’t know by looking at world if God is clever/good/loving

God could have been stupid → copying someone’s ideas/accidentally stumbled on this design after countless trials + errors

Hume’s criticism 6 of arguments for the existence of God

Universe is unique: so we are unable to say what it is like, what it could have been like, or how it must have come into being

→ Because we cannot have experience of any other way that things might have been

→ We don’t know how worlds are usually made/what degree of order to expect - so we can’t draw any firm conclusions

Hume’s main criticism of cosmological arguments

Can’t logically move from idea that everything in universe has a reason, to say that universe as a whole has a reason

→ Russell made a similar point: just because every human has a mother, doesn’t mean that whole human species has a mother

→ Overstepping rules of logic to move from individual causes of individual things to → view that the totality has a cause

→ Why can’t we accept that universe is eternal + cause of all things in it without looking for God as an explanation?