Every religion has great thinkers - philosophers who try to make sense of the mysteries of life. In the Christian tradition, one of the most well-known philosophers is Thomas Aquinas who lived in the 13th. Century AD.

He believed that if people thought carefully enough about the evidence, they would see that God must be real. Many philosophers over the centuries have offered arguments using evidence from around them to prove the existence of God.

The Cosmological Argument

One of the arguments that St. Thomas Aquinas used was the cosmological argument, which is based on the universe (the cosmos). This argument claimed that the universe itself was the most vital piece of evidence for the existence of God.

Aquinas explained that something could not come from nothing.

Every effect has a cause. The whole of life is a chain of cause and effect. Therefore, the universe must have been caused by something which existed before it. There has to be a cause that began everything - a first cause.

Think about it! In a domino rally, as each domino falls, it causes a chain reaction on every domino that follows. But something had to start the whole process. This something must also be eternal (without beginning or end) or otherwise it would have required to bring it into existence. So if we apply this argument to the Big Bang theory we wonder what caused the Big Bang. Could it have been God?

However, some philosophers argue that perhaps the universe itself is eternal so it would not require anything to bring it into existence. It simply exists in a 'steady state' of growth and development. Karl Marx, founder of Communism, held a similar idea. He believed that the only reality is matter. Matter is infinite and simply reproduces itself in the cause of evolution.

Draw an illustration or diagram which shows what St. Thomas Aquinas means when he says that there must have been a first cause. Do you think there was a first cause? Give clear reasons for your opinion.

The Argument From Design

There is plenty of evidence to suggest that explosions cause chaos. Therefore, how can the logic and order in the universe have come about from a Big Bang? Suppose you dropped a very expensive camera and then put all the pieces in a shoe box and shook it, what is the likelihood of all the pieces slotting together to form the camera again? In the same way, all the billions of elements of the universe may seem too organized to be the result of a sheer accident billions of years ago. Aquinas argued that this is strong evidence that there is a designer or creator at work.

A philosopher named William Paley (1743-1805) also argued for the existence of God from the starting point of design. He argued that if you came across a watch lying in the street - having never seen one before - you would look at it and see that its workings were extremely complicated. You would not think it appeared by chance, but assume the existence of a watch - maker who designed and put the watch together. In the same way, if you look at the world, you can see it is enormously complicated. Even something as small as the human eye is extremely complex. Could this really be the result of chance? Look at the way a bird's wings are perfectly suited to flying, and the delicate beauty of a snow flake, so light and small, so short lived, yet so complex.

Surely it seems logical to suppose there was a designer.

Divide your page into four equal parts. In each part, draw two items - one piece of technology and something similar from the natural world, to show how they compare e.g. a camera and an eye. 'The world is such a beautiful and orderly place, there must be a designer.' What do you think? Give your opinion and reasons.

The nineteenth-century scientist, Charles Darwin, developed the theory of evolution, which seems to destroy the arguments from design. He claimed that life evolved from very simple structures, through a process of natural selection, to reach the complex universe we now live in. Species survived by adapting to the changing conditions of the environment and so developed. Species that failed to adapt had become extinct. Human beings adapted very successfully to the changing environment. Their development into using tools, organising themselves into communities and increasing mental capacity were all signs of their ability to adapt.

Religious believers argued that God started the process of evolution knowing how the world would develop from it, and therefore he could still be seen as the designer. They would not believe that the world developing to this level of complexity was simply a matter of chance.

Some people accept BOTH the arguments from design and the theory of evolution. Explain how this is possible. 'Human beings are a species which has naturally evolved as the highest form of animal life'. Do you agree or disagree with this statement? Give clear reasons for your opinion.

The Argument Based on Morality

Where does our sense of right and wrong come from? Scientists agree that much of our behaviour is learned, but some are also convinced that we are born with a sense of right and wrong. If this is the case, where does this sense come from? Some people who believe that we are born with a sense of right and wrong think it must come from God, and that therefore this proves God's existence.

We can also think about individuals who are inspired by their belief in God to behave completely selflessly. We can think of such people as Mother Teresa, Gandhi and religious people in the local community who give tirelessly of their time to help others, who fit into this category.

How can their faith be so strong if there is no God? However, religious people who act selflessly do so because they have faith. They are convinced there is a God, but their feelings and experiences cannot prove the existence of God. So the fact that there are such people does not prove the existence of God, but shows that human beings can believe so strongly in something that they can resist their natural selfish inclinations.

The Argument Based on Probability

Many argue that it is not only possible to believe in God, but it is highly probable that God exists. They feel that there is so much evidence for the existence of God through the fact that the universe exists and that it is intricately designed, that so many people claim experience of God and that miracles are reported, that it is highly probable that God exists.

However, this argument is open to dispute. Looking at the evidence, it is no more probable that God exists than that God does not exist. There is an equal probability involved. The story which follows demonstrates this very well.

Two people (A and B) come upon a garden which appears to have been neglected. However, some plants seem to be very healthy and in places, the garden is extremely beautiful in spite of the weeds.

A says: 'It must be that a gardener has been coming here'

B replies: 'No, I don't think so. Just look at the weeds'

They ask several people who live beside the garden, but no one has ever seen any one working there.

A says: 'He must have worked while people slept.'

B responds: 'No, someone would have heard him. Anyway, anyone who cared about plants would have kept the weeds down.'

They examine the garden ever so carefully, and sometimes they find new things that suggest that a gardener comes and sometimes they find new things that suggest there is no gardener or even a malicious person may have been at work. They also study what happens to the gardens that are left without attention. However, they still disagree about whether there is a gardener.

A says: 'But look at the way these plants are arranged. There is a definite feeling for beauty here. There must be a gardener.'

B says: 'I doubt it, but we can make sure.'

So they set up a barbed wire fence. They electrify it and they patrol it with bloodhounds. But no shrieks ever suggest that some intruder has received an electric shock. No movements of the wire ever betray an invisible climber. The bloodhounds never bark as though someone was there. And the garden continues to blossom.

A declares: 'There must be a gardener, but he is invisible, intangible, insensitive to electric shocks, a gardener who has no scent, makes no sound, a gardener who comes secretly to tend the garden he loves.'

B responds: 'Just how does what you call invisible, intangible, eternally elusive gardener differ from an imaginary gardener or no gardener at all.'

So, after all their searching, A still says, 'I believe that a gardener comes,' while B says 'I don't.' But their beliefs make no difference to what they expect to find in the garden.

What, then, is the difference between them? The difference lies in how they feel towards the garden rather than in the garden itself

Summarise the parable of the gardener in not more 100 words. How does it help to explain different beliefs about the existence of God? Why is A still convinced that there is a gardener after all their searching? Show how this view is helpful in understanding how a person can believe in a God that cannot be seen or touched. In pairs summarise all of the arguments for the existence of God in not more that 50 words each. Note down the objections to each of the arguments, using examples where possible. Which argument do you think a believer would find the most convincing? Give reasons for your opinion.