Cosmological Argument for Existence of God

Is Big Bang Cosmology of Relevance?

Cosmological Arguments1. One form tries to show that the series

of causes can’t go back to infinity– Aquinas’s First and Second Way– Kalam Cosmological Argument (Craig)

2. Another form tries to show that at least some being must exist necessarily

– Aquinas’s Third way– appeal to a “principle of sufficient

reason”, which holds that everything can be explained

Aquinas’s Five Ways

• The classical cosmological arguments come from St. Thomas Aquinas’s Five Ways.

• The first three are usually called cosmological arguments.

• Arguments one and two aim to show that infinite series of causes are impossible

• Argument three tries to prove the existence of a necessary being.

The First and Second Ways

• The first and second ways have a very similar structure. We will consider only the second in detail

• The first way deals with change – the word is sometimes given as “motion.”

• It argues that all change must have a cause, and that the series of causes can’t go back to infinity.

Continued

• The second way deals with “efficient causes.”

• We will take this to mean: causes that sustain things in being – “sustaining causes.”

• It may be that the sun (which provides energy to the earth) is a sustaining cause of your existence.

• It may be as well that electromagnetic forces are sustaining causes of you

The Second Way Stated

• Aquinas’s Second Way:– Some things are caused (sustained) by

other things, which are caused by other things...

– Nothing is the cause of itself– To take away the cause is to take away the

effect.– If there is no first cause, there will be no

intermediate causes and hence no immediate causes of what’s here and how.

– But what’s here and now has causes.– Therefore, there is a first cause: God.

In Plainer English

• Aquinas notes that many things (all things?) that we see around us are kept in being by other causes.

• Some of these causes have their own sustaining causes.

• He goes on to claim that chains of sustaining causes can’t stretch back to infinity

What Kind of Argument?

• Aquinas’s argument is a posteriori in one sense: it starts with observable facts

• The proof proceeds by reductio ad absurdum

• In other words, Aquinas tries to show that if we believe in infinite series of causes, we end up in contradiction

The Contradiction

• Aquinas assumes plausibly: to take away the cause is to take away the effect

• If the sustaining causes of what we see around us didn’t exist, neither would those things

• If we take away the first cause, he says, we take away all the things that depend on it

• This implies that things we know to exist don’t exist: contradiction

The Problem

• To say there’s no first cause isn’t to “take away” any cause.

• It’s just to say: every cause has a cause in turn

• That may be puzzling, but...• Aquinas hasn’t proved that it’s

impossible to have an infinite series of causes

A More Sophisticated Version

• Aquinas doesn’t seem to have shown that infinite series of sustaining causes are impossible

• William Lane Craig might argue: Aquinas made a mistake in allowing that the bare idea of an infinite series of actual things is possible

• Craig argues that “actual infinities” are themselves impossible

• His argument (based on an older Islamic argument) is called the Kalam Cosmological Argument

A Diagram of Craig’s Argument

In Words:

• Craig considers several alternatives• Either the universe had a beginning or it

didn’t. He argues that it did.• He argues this because assuming

otherwise means assuming an actual infinity of past events

• He believes this is impossible• We will consider this in detail, but first...

The Kalam Argument Continued

• Suppose the universe had a beginning• Craig says: the beginning was either

caused or uncaused• He repudiates the second alternative;

he thinks it’s absurd• Finally, he argues that the cause must

have been personal: it was God

Three Problems• We will see that• 1) Craig doesn’t succeed in showing

that an infinite series of causes is absurd

• 2) He doesn’t show that an uncaused universe is absurd

• 3) And although his remarks about a personal cause are suggestive, they aren’t a proof

*The Heart of the Argument

• The core of Craig’s argument is the “proof” that there can’t be an actual infinite series of causes.

• Some may think that talk of infinity is inherently confused or absurd

• Craig does not go this far.• He accepts the mathematical theory of

infinity.

*Mathematics and Infinity

• We first need to ask: when to two sets have the same number of things?

• The mathematician’s answer: when their members can be paired one-one:– {a,b,c,d,e} – {v,w,x,y,z} vs– {a,b,c,d,e,f}– {v,w,x,y,z}

*Infinity

• We can compare infinite collections in this way. This implies: the number of counting numbers equals the number of even numbers:– 1 2 3 4 5 6 7 8 9 10...– 2 4 6 8 10 12 14 16 18 20...

Continued

• Note what mathematicians mean here• The phrase “same number” originally

did not apply to infinite collections• Mathematicians found a way to extend

the definition: to use the phrase consistently in a new context

• The new use agrees with the old use, but extends that use

*Craig and Infinity

• Craig agrees that the mathematical theory of infinity is consistent

• He agrees that we can say things like– The number of even numbers equals the

number of counting numbers– The number of counting numbers is less

than the number of real numbers• He believes that we get absurdities only

when we talk of concrete infinities

*Absurdities?

• Craig brings up an example from the mathematician Cantor

• Imagine an infinite bookshelf with books alternating black, red, black, red, black...

• Now imagine borrowing all the red books

• How many books are left? Answer: the same number as there were originally

• Craig says: this is clearly absurd

*A Reply

• The claim that there are just as many books left may sound absurd. However,

• All it means is that there is a one-one function pairing the total set of books with the set of black books

• Craig’s admission that the mathematical theory is consistent requires him to agree that this is consistent

*Further...

• We can still make sense of our feeling that there are “fewer” books left.

• We simply need to speak carefully.• It is still true that the remaining books

are a proper subset of the original collection

• This captures an important sense in which the set of remaining books is "smaller"

*A Worse Absurdity?• Craig continues: suppose all the red books

have been removed. We can fill in all the gaps in the shelf with the remaining books

• How? Move the 2nd black book to where the first red book was.

• Then move the 3rd black book to where the 2nd black book was

• And so on and so on and so on• The result: all the gaps are filled• Craig’s judgment: this is absurd

*What Kind of Absurdity?

• There is no contradiction in what has been described. It is mathematically consistent.

• It is certainly surprising and puzzling.• However, a good deal of what we have

learned from modern science is surprising and puzzling

• This is different from saying it is absurd

*Furthermore

• We may think that we could never fill in the gaps this way, and

• This may be perfectly true. • (It might require infinite time and infinite

energy)• However, the idea that an omnipotent

God couldn’t do it is much less clear

*The Kalam Argument and Omnipotence

• Craig’s argument contains a theological danger

• It appears to rule out the possibility of God doing things that on the face of it seem possible for divine being

• For example: couldn’t pick out a straight line in space, and put a stone every mile along the line?

• If not, why not? Is this really absurd?

*Absurdity Again

• If we can show that something is internally contradictory (a square circle, e.g.), it is absurd

• Craig hasn’t shown that• If we can show that something

contradicts a known fact, we have an absurdity

• Craig hasn’t done that either.• Therefore, the first step of Craig’s

argument is at best highly inconclusive

Recap

• Aquinas’s First and Second Ways try to prove that certain kinds of infinite causal chains are impossible

• The arguments seem weak: either confusing denying a first cause with taking away a cause or simply assuming what needs to be proved

• Craig tries to prove that actual infinities are absurd

• All he succeeds in showing is that they would have some surprising properties

Craig Continued

• Suppose we agree with Craig that the universe has a beginning

• We can ask: does the rest of his argument work?

• Does he show that the beginning must have been caused?

• Does he show that the cause must have been personal?

The First Cause

• Craig seems to think that if the beginning of the universe wasn’t caused, then the universe must simply have “popped into existence”

• He thinks that no reasonable person would accept this

• There is a problem with this way of putting things

The Beginning of Time

• If the universe “popped into existence,” that would suggest a time before the appearance of matter

• This ignores a different possibility: there is no time “before” the beginning of the physical universe

• The universe could be nothing more than the sum total of the events and objects it contains

A Personal Creator?

• Suppose we agree that it’s plausible that the beginning of the physical universe had a cause

• Something Craig doesn’t stress: that cause couldn’t be physical.

• Why not? Because if it were physical, it would simply be another part of the universe, and Craig would say that it needs a cause

Continued...• If the beginning of the universe has a

cause, it must be something that it not physical

• Plausibly, this also means something not in time.

• (Why? Because things in time are arguably physical, though this is controversial)

• Therefore, plausibly, the cause of the universe would have to be eternal – outside time

Eternal Cause?

• Craig asks: if the cause is eternal, why wouldn’t the effect be eternal too?

• Craig’s answer: we can make sense of this if we assume that God eternally intended to create a universe in time

Necessary Beings

• So far, we have considered arguments to show that there can’t be an infinite series of events or causes

• Another important kind of cosmological argument tries to show that there must be at least one necessary being – a being that couldn’t’ fail to exist

• This being, it is argued, is God

Aquinas’s Cosmological Argument

• Some things begin and end (we’ll call them evanescent things)

• If everything was evanescent, there would have been a time when nothing existed

• If there was a time when nothing existed, nothing would exist now.

• Since that’s false, there’s something (God!) that isn’t evanescent

An Obvious Problem

• Suppose everything is evanescent. • Just because each thing was non-

existent at some time doesn’t mean that at some one time each thing was non-existent

• Compare: everyone has a mother. But no one person is everyone’s mother.

In short...

• Aquinas’s argument doesn’t show that there must be a necessary being.

• Still, the intuition Aquinas starts with is interesting: if every single thing is contingent, it’s remarkable that anything exists.

• To explore this idea, we need a different approach

A Deeper Principle

• Leibniz (1646-1716) said:– No fact can be real or existent, no

statement true, unless there be a sufficient reason why it is so and not otherwise.

• This is the Principle of Sufficient Reason (PSR)– In short: everything has an explanation

A Problem with the Principle

• Some things don’t seem likely to have sufficient reasons

• For example: suppose that no one at this moment is exactly 5 feet 10.37821 inches tall

• That precise fact (a negative fact) may have no sufficient reason

A Restatement of the Principle

• William Rowe suggests revising the principle:

• Every thing and every positive fact has a sufficient reason

• This avoids the problem described above

• (Note: Rowe still ends up rejecting the PSR)

What is a Sufficient Reason?

• A sufficient reason must explain whatever it’s intended to be a reason for

• That means that it must imply what it’s a reason for: if X explains Y, then Y follows from X; it’s impossible for X to be true and Y false.

• Further, in the case where Y is contingent, X can’t just be Y restated.

Comment on Previous Slide

• Some things (necessary truths – e.g., 2+3=5) may be "self-explaining"

• Contingent truths – things that might not have been so – can't be self-explaining

• (If you suspect otherwise, try to find a good example of a self-explaining contingent truth)

• So if Y is contingent, and X just restates Y, X can't be the sufficient reason for Y

A Principle

• To evaluate the PSR, we need to understand another principle: the Transfer of Necessity

• This principle is a matter of logic. It says:

• If X is a necessary truth (i.e., couldn’t be false no matter what) and X implies Y, then Y is also necessary.

Why?

• Suppose X is necessary, X implies Y and Y is contingent.

• In that case, we can imagine a case where Y is false. But since X is necessary, X would be true in that case

• Since X implies Y, Y would have to be both true and false in that case – which is absurd.

Put another way...

• If X is necessary, and X implies Y, then it’s impossible for Y to be false.

• If Y were false, then the principle we just described would imply that X is false.

• That can’t happen if X is necessary• Thus, necessary truths only imply other

necessary truths

Problems for the PSR

• Consider the collection of all positive contingent truths. This is itself a contingent truth, which we’ll call F

• Suppose R is a sufficient reason for F. Then R can’t be a necessary truth (because necessary truths don’t imply contingent truths.

Continued• Suppose that R is contingent (the only

other alternative). Then • R can’t be a mere “part” of F because in

that case it won’t imply F• R can’t be identical to F because then R

won’t explain F• R can’t be a negative (or partly

negative) fact, because it’s obscure how a negative fact could explain a positive fact

Putting it another way...

• If R is necessary, then R doesn’t imply the contingent truth F

• If R is contingent, then R itself needs a sufficient reason, and circularity or regress threatens.

• Therefore, whether R is necessary or contingent, R can’t be the sufficient reason for F

The Upshot

• It appears that nothing could explain the totality of positive contingent facts

• If so, then the PSR is false• If so, then the versions of the

Cosmological Argument based on the PSR fail

A Different Approach

• Let’s ask: why are there any contingent things?

• No purely necessary truth could explain this (because the fact that there are contingent things is contingent – the whole point of our initial worry)

• No appeal to a contingent thing could explain it (because that thing would be the very sort of thing we're trying to explain)

• But... perhaps a combination of a necessary thing and contingent facts could explain it

An Example from Quentin Smith

• Suppose that space-time exists necessarily.

• Suppose that space-time embodies a "quantum vacuum."

• Quantum vacuums sometimes create real particles spontaneously

• A necessary space-time that contingently contains a quantum vacuum would imply the existence of contingent things.

Note carefully

• The explanation under consideration combines necessity and contingency

• But we can ask: does it address the real issue? Does it provide a satisfying reason for the existence of contingent things?

• The answer to that question isn’t clear

Another Variation

• Suppose there is a necessarily existing omnipotent being

• Suppose this being contingently wills the existence of contingent things

• It follows that contingent things will exist• Is this any more satisfying?

Satisfying vs. Sufficient

• The word "explain" has been used so far with "imply" as part of its meaning

• Sometimes, we take something to be "explained" if certain facts "make sense" of it – provide an intellectually satisfying account

An Example

• Suppose Teresa is considering whether to go to grad school in philosophy or in psychology

• She decides on psychology; we ask her why• She says that though she likes the intellectual

freedom of philosophy, she gets great satisfaction from looking for patterns in data

• This explanation doesn't necessitate or imply her decision, but it makes sense of it

A Bit More Detail

• If you think decisions are free, then you think the facts about what led up to them don't imply them.

• But you may think that those facts can make sense of them – especially if the facts include good reasons

Satisfying Reasons

• Suppose that God creates contingent things for good reasons, even if God didn’t have to do so.

• The good reasons would satisfy our desire to understand why contingent things exist

• The explanation would provide a satisfying reason for the existence of contingent things

The Principle of Satisfying Reasons

• Perhaps the following principle is true

There is a satisfying reason for the existence of contingent things

• It is not clear how we would know that such a principle was true.

Necessary beings?

• What kinds of things could exist necessarily?

• Are minds the kinds of things that could exist necessarily?

Questions• Suppose there is a necessary being that

explains contingent beings. We can ask:

WHY MUST THE NECESSARY BEING BE GOOD, WISE, INTELLIGENT...?WHY COULDN’T IT BE SPACE-TIME OR MASS/ENERGY OR SOME ABSTRACT PRINCIPLE?WHY MUST THAT BEING BE THE GOD OF RELIGION?WHY WOULDN’T A WISE, CARING BEING ITSELF NEED A SUFFICIENT REASON?

Summing Up• The Design Cosmological Arguments

reflect our desire to make sense of things

• One sees signs of design in the patterns of nature

• The other sees the existence of contingent things as calling for a deep explanation

• Each is suggestive; neither is conclusive

Fine Tuning and the Anthropic Principle

Fine-tuning Design Arguments

• An important kind of argument concentrates on large-scale facts about the universe

• These arguments are called fine-tuning arguments.

Robin Collins’s Analogy

• Suppose we discovered a planet where there was

• A domed structure• With an oxygen-recycling system• Ideal temperature and humidity range

for life• Water-recycling systems• Food production systems

Collins’s Point

• We would not agree that this system was a product of chance

• We would see it as a product of intelligence, but

• a) Earth itself is such a system, and• b) More generally, various feature of the

universe are fine-tuned for life

Examples of Fine-Tuning: Gravity

• Gravity: if the gravitational constant were only a little stronger, mammals our size would be crushed. Stronger yet and all stars would be red dwarfs – not warm enough to support life

• If gravity were a little weaker, all stars would be blue giants – they don’t exist long enough for life to develop

Another Example: Strong Nuclear Force

• This force keeps atoms together by resisting electric repulsion.

• A 1% increase would lead to almost all carbon being burned into oxygen; a 2% increase would prevent protons – and hence atoms – from forming

• A 5% decrease would mean a universe with no molecule more complex than hydrogen

The Cosmological Constant

• This is the energy density of empty space

• This constant is very close to zero• If it were even slightly larger, the

universe would expand far too rapidly for stars, galaxies, planets and hence life to form

The Point Again

• The constants of the universe seem to make the universe into an “irreducibly complex system” from the point of view of life

• That is: tamper even a little with even one of the many fine-tuned constants, and there would be no life

Probability

• The point can be put in probability terms: given the range of values open “a priori” to the constants, it is fantastically improbable that by chance alone, they would permit life

• However, if an intelligent designer is responsible for their values, the fine-tuning is no longer improbable.

Objection: Other Life-Forms

• The fine-tuning argument points to various physical conditions necessary for life, but

• It doesn’t take account of the fact that our form of carbon-based life may not be the only possible form

Reply:

• For the most part, the fine-tuning argument doesn’t focus on the details of life-forms (e.g., carbon vs. silicon)

• Instead it focuses on such things as the possibility of atoms of any sort, or of stars that can provide energy, or of the possibility of chemical processes

Objection: “Fundamental Law”

• Perhaps there is a fundamental law that• underlies more specific physical laws,

and• Implies that the constants have the

values that they have• If so, the fine-tuning would be explained

by reference to this fundamental law

Replies

• First, the hypothesis is sheer speculation

• (However, the objector might reply that it represents a coherent possibility – just as God does)

• Second, it would just allow a new version of the question. We could ask: why this fundamental law, rather than some other?

• Why a fundamental law that calls for these values of the constants?

Further to the second reply

• John Leslie points out that our scientific models allow for other sorts of universes with other sorts ranges of constants.

• Therefore, there is no good reason to believe in such a fundamental law

Objection: The universe had to be some way

• The universe had to have some set of laws

• Further, there’s no reason to think any one detailed set more improbable than any other.

• Looked at in this way, there is nothing to explain

A Comparison

• Suppose we consider a bridge hand. The chance of someone being dealt that particular, specific bridge hand is very small

• However, we don’t think there’s any need to explain why someone got this bridge hand as opposed to any other equally improbable hand

Reply• If we carry this reasoning to its limit, then

nothing requires explanation.• This is because every situation, if considered in

enough detail, is improbable• For example: the precise arrangement of the

mess on my desk is improbable, but calls for no explanation.

• But if the papers were stacked so that they formed a series of arches, that would require explanation

Continued

• Some values for constants would seem merely “random” or uninteresting – not in need of explanation

• The fine-tuning arguer says: the constants of our universe aren’t like that. They fit together too remarkably when looked at from the point of view of life

• Hence, they need to be explained.

Objection: the Anthropic Principle

• The (weak) anthropic principle says that the laws of the universe are “restricted” by the conditions necessary for their being observed

• Translation: we couldn’t know that the constants are what they are unless those constants were consistent with the existence of observers

• Supposed conclusion: we shouldn’t be surprised to find that the constants permit life

Reply

• Of course we couldn’t observe constants that ruled out our existence, but

• The constants could still be improbable• If we had discovered that a wide range

of constants was compatible with life, the fine-tuning argument couldn’t get off the ground

• What is surprising is that the constants came out right even though “right” is such a narrow range.

Compare (John Leslie's Example)

• Suppose that five minutes ago, I was blindfolded and fired at by 100 marksmen with loaded rifles.

• I couldn’t observe that I’m still alive unless all the marksmen missed

• However: it’s still surprising that I’m alive, and calls for explanation

Objection: Many Universes

• Some physicists have posited theories that imply the existence of many “sub-universes” with differing laws and constants

• If enough such universes exist, with enough variety, it wouldn’t be surprising that one or more permitted life

Compare:

• If you toss a coin 10 times in a row and get 10 heads, you will be surprised.

• But if 1,000,000 people each toss a coin 10 times, then it would be surprising if no one got 10 heads in a row. (The chances of 10 heads in a row are 1 in 1024 for one tosser.)

Reply

• If the many-universes hypothesis is true, it would provide an alternate explanation for “fine-tuning”

• But there isn’t any empirical evidence for many universes, and the theoretical arguments are very controversial

Still...• If the theoreticians can make the many-

universe view respectable (show that it fits well with other pats of physics, is elegant, could explain a great deal...) then it would be a legitimate rival to fine-tuning theistic explanations

• Compare: we said earlier that evolution does most of its work against Paley by providing a legitimate rival view

• We would then need to decide which view is overall more likely

And Still Further...

• That is something people could disagree about.

• Therefore: if many universes are a good theoretical idea, that doesn’t mean that theistic design is a bad idea

• It means instead that we have more than one viable hypothesis