Probability That God Exists – Is There Such a Thing?

probability that god exists

Many individuals claim they have found “proof of God”. Unfortunately, our physical universe doesn’t provide this evidence.

But, is there a way to determine the probability that god exists? In this article we explore this option using a mathematical model which relies on relationships between what can and cannot be known.

Bayes’ Theorem

The Bayes’ theorem is an invaluable statistical tool in fields like medicine and machine learning, where it demonstrates how new evidence can change the probability of a hypothesis. When something unlikely comes along, its impact increases relative to that original hypothesis – because odds against an event can be multiplied with its magnitude to calculate inverse probabilities.

Skeptics will find this theorem particularly helpful, as it allows them to assess the likelihood that God exists against other theories. But it should be remembered that this theorem does not definitively prove or disprove anything, only providing estimates as to its likelihood. Therefore, its use should not be used for subjective decisions but instead used objectively as a way of judging competing claims with evidence-backed claims.

As previously discussed, adding new evidence can alter the probability of any hypothesis but cannot reduce it. For example, being diagnosed with an illness will decrease their prior probability for having said illness but this does not imply they no longer are sick; rather it means their prior probability was unknown prior to diagnosis but now known.

As evidence emerges, it’s essential that context be taken into account when calculating its probability. When considering God, this means examining whether He exists without offering excuses as to why things happen; any excuses provided must then be multiplied by the prior probability without them so He does not become more probable due to them.

Swinburne uses this methodology to conclude that evidence prior to religious experience provides at best a posterior probability of one-half for God’s existence; this is roughly equivalent to flipping two coins and getting heads both times, something many believers find dismaying. Unfortunately, this finding comes down to evidence supporting God being nonexistent outweighing evidence supporting God being real. This results in disappointing findings for believers but it simply proves how weak proof can be when considering existence versus nonexistence arguments.


If a physicist were asked to determine the probability that an invisible being existed, he may struggle to produce an exact figure due to several variables influencing his findings such as one’s beliefs about God and His impact on creation. But one Manchester University graduate from Ohio who now works as a risk management consultant has taken up this challenge and developed an equation which claims there is 67% chance that an omnipotent being exists.

Stephen Unwin employed the Bayes Theorem method for his calculations based on probabilities. This mathematical tool was first devised by European philosopher Thomas Bayes in the mid-18th century and typically used to assess event likelihood based on various factors balancing against each other. Unwin documented his use in his book The Probability of God along with an Excel spreadsheet detailing all data used so anyone can try replicating these calculations themselves.

Unwin’s goal is to strike a balance between cold logic of probability and spiritual faith, to allow humans to rationally hold faith. He states that faith cannot be eliminated as part of spirituality and must help explain our world around us.

An illustration of the fine-tuning hypothesis can be seen by considering that life on Earth and human evolution are highly likely to have occurred by chance alone, without certain physical constants such as gravity and Planck’s constant. According to this theory, without these constants supporting life emergence in the universe would have been impossible.

However, this argument makes an incorrect assumption: that all quantities have equal chances of occurring. This is incorrect since this assumption simply is not true: certain numbers such as boys versus girls birth rates tend to occur more often due to biological reasons which ensure more boys will survive than girls due to men dying sooner than them.


Neurosurgeon Michael Egnor and atheist broadcaster Matt Dillahunty recently debated whether God exists. While their opinions varied widely on evidence for or against its existence, Egnor cited empirical proof for God while Dillahunty insisted there is no way scientifically to prove God exists citing physical experimentation as verification criteria for theories.

Problematic with this argument is its limitation to empirical observations; thus leaving out many relevant factors, including spiritual experience which cannot be experimentalized; Catholic Church believes knowledge of God cannot be proven or disproved, relying instead on faith for its validation.

Further, many scientists contend it is unreasonable to invoke God as an explanation for scientific laws. Biologist Richard Dawkins asserts that natural laws can be explained without recourse to supernatural forces; for instance, evolution can be explained via random mutation and natural selection processes.

Atheists take the position that invoking God to explain natural law is unnecessary and that there is no empirical evidence supporting God’s existence. But an alternative viewpoint holds that his existence is more probable than any other explanatory hypothesis.

Notably, probabilities should always be interpreted in relation to some additional data. For instance, the probability of rolling a 1 on a six-sided die is equal to all possible events and the same principle holds for God’s existence – for an accurate calculation you should divide whatever event is being considered by all possible events that could take place simultaneously.

Anthropic reasoning asserts that our Universe appears finely tuned for life to exist – this presents cosmologists with a challenge as they attempt to explain why certain parameters and laws of the Cosmos exist as they do, though it doesn’t necessarily imply it was created by some intelligent intelligence.


Many people believe in God, yet no physical evidence can prove His existence. Since He cannot be directly observed or proved through direct observation, however it is possible to estimate His probability using available evidence – this method being based upon Bayes’ theorem which states that new events can be predicted based on prior knowledge combined with results of previous events which will create a new probability that an event will happen in future.

Stephen Unwin applies his theory of probability to six areas of evidence to ascertain how probable God’s existence is. These areas include recognition of goodness, natural evil, intra-natural miracles, extra-natural miracles and religious experiences – the latter two having subjective elements as their assessment is dependent on his personal assessment. Unwin concludes that God likely exists at 67% probability but notes this figure depends heavily on subjective interpretation of evidence.

Unwin argues that without God there would not be much moral truth, as evidenced in the Hiroshima bombing. Unwin quotes Richard Swinburne who asserts that moral truth can either be necessary or contingent; either type is highly unlikely in an alternate universe without its creator.

Unwin also uses logic analysis to demonstrate that natural laws could never exist without God; he also mentions how His creation of them wasn’t random but rather was designed with purpose in mind.

Unwin does not attempt to prove God exists, but believes it reasonable for some people to believe He exists. A god-based explanation would likely be more convincing than any non-god based ones for explaining how the universe operates.

Theistic believers often assert that our physical universe is an intricate and diverse creation, leading them to believe there must be a God behind its formation. Humans cannot explain its complexity either. Yet the scientific method requires theories be verifiable via physical experiment, making theistic arguments unlikely ever meet this standard.

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