The perils of faith.

Definitions of faith.

"Faith consists in believing what reason does not believe," wrote the eighteenth century French philosopher Voltaire [Philosophical Dictionary, Inondation]. Surprisingly, the Catholic Church endorses that view. It has stated that faith is not based on credibility, nor on the accumulation of probabilities [First Vatican Council session v and Lamentabile Dictu Proposition 25.]

Faith goes further still. Voltaire again: "Faith consists in believing, not what appears to be true, but what appears to our understanding to be false" [Philosophical Dictionary,, Foi].

The very impossibility of the articles of Christian faith made them attractive to the second century Christian father Tertullian:

The Son of God died; this is by all means to be believed, because it is absurd. And after being buried, he rose again: this is certain, because it is impossible.
[On the Flesh of Christ, v.]

Faith in unfalsifiable hypotheses.

Faith in untimed predictions.

A third category of unfalsifiable beliefs are untimed predictions of improbable events, such as the Second Coming of Christ, the Resurrection of Bodies, and the Last Judgement.

These predictions often begin life as testable claims, with a clear time frame. Jesus himself expected the Kingdom of Heaven to arrive imminently [Joachim Jeremias, New Testament Theology, vol 1, SCM Press, London 1971] and predicted that the Son of Man would arrive before his disciples had finished going through the cities of Israel [Matthew 10.23]. St Paul expected the end to come within the lifetime of many living Christians, and they should live free of commitments, so they would be ready. [1 Corinthians 7.29-31]

These predictions were falsifiable - and they were falsified.

Early Christians continued to believe that the Second Coming was imminent. But as the decades rolled by, with endless wars but no End of Time, they faced continual taunts and doubts. To put an end to these, the event was deferred to an unspecified time in the future, which might be near, or far.

And there it remains today, two thousand years later. The claim is now framed in a way that cannot be falsified - however many millennia pass.

Faith in the impossible.

Faith is needed to believe in events that are normally impossible - and therefore inherently unbelievable.

These events are of three main types.

• The first is the miracle: an "event" that occurs in a normal context, but which is normally impossible by the laws of nature. Examples are the virgin birth, the resurrection of Jesus, Mohammed's night ride to Jerusalem and so on.

  Some people believe that miracles still occur in the present. But the miracles that are critical foundations for religion happened in the remote past.

  Historians have well-tried means of validating whether past events occurred - reliability of sources, confirmation by other sources, textual criticism, archeological evidence, carbon dating and so on. The more improbable the claim, the higher the standard of evidence required to prove it. The proofs for the virgin birth, for the resurrection, and for Mohammed's night ride to Jerusalem, are not of the type that most historians would accept on any other type of matter.

  But faith does not require proof, and those who demand proof are derided by the faithful as doubting Thomases. Indeed, if historians were to prove the claims of faith beyond all doubt, they would cease to be matters of faith.

• A related type of normally impossible "event" is the revelation. A god, or a divine messenger, speaks to a chosen prophet to deliver the central message of the religion.

  Such revelations usually occur without witnesses, in inaccessible places. They depend on the word of a single person and the authority or force they can muster to validate it. Zarathustra's received his message by a lonely mountain stream, from the archangel Vohuman. Moses's commandments were delivered on the top of a mountain where others were forbidden to go. Mohammed was first addressed in a remote cave by the archangel Gabriel. Unusually, Mohammed also saw Gabriel while in the company of other people like his wife Khadija, but no-one else saw the angel. However, this was not taken as evidence that Mohammed was hallucinating, but that he was being granted a unique privilege.

• The third type of impossibility is the predicted irruption of a supernatural realm into this world. We have already covered this under untimed predictions.

Faith in self-contradictions.

The articles of faith we have been discussing so far are not matters of everyday experience, but at least they are not totally unthinkable.

The final type of article of faith is unthinkable in human terms, because it implies a self-contradiction.

The most serious category of these is the logical contradiction within a single proposition - such as the claim that Christ is both fully divine and fully human at one and the same time. Greeks and Romans accepted to some extent that humans could be semi-divine - Hercules, Alexander, and the Roman emperors are examples. But in the traditional Jewish and Old Testament scheme, which Christians still accept as part of their scripture, the divine was totally separate from the human, and the two categories could never be combined in one person.

The doctrine of the Trinity is an even more glaring logical contradiction. God is one and three at the same time. His threeness in no way detracts from his oneness - and vice-versa.

In the second category, the system contradiction, two different beliefs which are part of the same religious creed conflict with each other.

Most Buddhists, for example, believe there is no Self: human beings are just aggregates of fleeting matter and sensations. However, Buddhists also believe in reincarnation.

But if there is no self, then there is nothing to be reincarnated, and nothing that can teach or be taught about enlightenment. As the most brutally frank of all Buddhists, Nagarjuna, admitted:

No truth has ever been taught by any Buddha for anyone, anywhere.

Self-contradictions have caused dissension and sectarianism in religions that harbour them. Christianity's two focal contradictions underlie many of the bitter controversies in the history of the Church, while Buddhism's central contradiction led to the emergence of Mahayana schools of sudden enlightenment and the identity of nirvana and phenomena.

Faith requirements of major religions