Stephen D. Unwin
Encyclopedia
Stephen D. Unwin is a physicist
and author best known for his book, The Probability of God. Unwin is a graduate of Imperial College London
and received his doctorate in theoretical physics from the University of Manchester
for his research in the field of quantum gravity
. Formerly the technical attaché to the United States Department of Energy
for the British government, he is president of his own consulting firm, specializing in risk management for various Fortune 100 clients.
In his book, Unwin argues that a mathematical equation
developed by Thomas Bayes
can be used to calculate the probability
that God exists. He does not make the claim that application of this method produces an absolute probability on which everyone would agree, but that it provides a systematic way of ordering one's ideas, weights of belief, and uncertainties in order to determine their implications regarding the probability that God exists.
Unwin employs Bayesian probabilities, a statistical method devised by Reverend Thomas Bayes. He begins with a 50 percent probability that God exists (arguing that 50–50 represents "maximum ignorance"), then applies a modified Bayesian theorem:
In this model, the probability of God's existence after the evidence is considered is a function of the probability before times D ("Divine Indicator Scale"): 10 indicates the evidence is 10 times as likely to be produced if God exists, 2 is two times as likely if God exists, 1 is neutral, 0.5 is moderately more likely if God does not exist, and 0.1 is much more likely if God does not exist. Unwin offers the following figures for six lines of evidence: recognition of goodness (D = 10), existence of moral evil (D = 0.5), existence of natural evil (D = 0.1), intranatural miracles (prayers) (D = 2), extranatural miracles (resurrection) (D = 1), and religious experiences (D = 2).
Plugging these figures into the above formula (in sequence, where the Pafter-figure for the first computation is used for the Pbefore-figure in the second computation, and so on for all six Ds), Unwin concludes: "The probability that God exists is 67%." But then he notes that "this number has a subjective element since it reflects my assessment of the evidence." Unwin's comment refers to his estimates of the various "D" values used to obtain his estimate, whose values would be disputed by many. As was Unwin's stated intent, others have applied his formula to produce different probabilities, such as the skeptic Michael Shermer
in Scientific American
(2%). In his book The God Delusion
, Richard Dawkins
includes an extensive critique of Unwin's methods.
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
and author best known for his book, The Probability of God. Unwin is a graduate of Imperial College London
Imperial College London
Imperial College London is a public research university located in London, United Kingdom, specialising in science, engineering, business and medicine...
and received his doctorate in theoretical physics from the University of Manchester
University of Manchester
The University of Manchester is a public research university located in Manchester, United Kingdom. It is a "red brick" university and a member of the Russell Group of research-intensive British universities and the N8 Group...
for his research in the field of quantum gravity
Quantum gravity
Quantum gravity is the field of theoretical physics which attempts to develop scientific models that unify quantum mechanics with general relativity...
. Formerly the technical attaché to the United States Department of Energy
United States Department of Energy
The United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material...
for the British government, he is president of his own consulting firm, specializing in risk management for various Fortune 100 clients.
In his book, Unwin argues that a mathematical equation
Bayes' theorem
In probability theory and applications, Bayes' theorem relates the conditional probabilities P and P. It is commonly used in science and engineering. The theorem is named for Thomas Bayes ....
developed by Thomas Bayes
Thomas Bayes
Thomas Bayes was an English mathematician and Presbyterian minister, known for having formulated a specific case of the theorem that bears his name: Bayes' theorem...
can be used to calculate the probability
Probability
Probability is ordinarily used to describe an attitude of mind towards some proposition of whose truth we arenot certain. The proposition of interest is usually of the form "Will a specific event occur?" The attitude of mind is of the form "How certain are we that the event will occur?" The...
that God exists. He does not make the claim that application of this method produces an absolute probability on which everyone would agree, but that it provides a systematic way of ordering one's ideas, weights of belief, and uncertainties in order to determine their implications regarding the probability that God exists.
Unwin employs Bayesian probabilities, a statistical method devised by Reverend Thomas Bayes. He begins with a 50 percent probability that God exists (arguing that 50–50 represents "maximum ignorance"), then applies a modified Bayesian theorem:
In this model, the probability of God's existence after the evidence is considered is a function of the probability before times D ("Divine Indicator Scale"): 10 indicates the evidence is 10 times as likely to be produced if God exists, 2 is two times as likely if God exists, 1 is neutral, 0.5 is moderately more likely if God does not exist, and 0.1 is much more likely if God does not exist. Unwin offers the following figures for six lines of evidence: recognition of goodness (D = 10), existence of moral evil (D = 0.5), existence of natural evil (D = 0.1), intranatural miracles (prayers) (D = 2), extranatural miracles (resurrection) (D = 1), and religious experiences (D = 2).
Plugging these figures into the above formula (in sequence, where the Pafter-figure for the first computation is used for the Pbefore-figure in the second computation, and so on for all six Ds), Unwin concludes: "The probability that God exists is 67%." But then he notes that "this number has a subjective element since it reflects my assessment of the evidence." Unwin's comment refers to his estimates of the various "D" values used to obtain his estimate, whose values would be disputed by many. As was Unwin's stated intent, others have applied his formula to produce different probabilities, such as the skeptic Michael Shermer
Michael Shermer
Michael Brant Shermer is an American science writer, historian of science, founder of The Skeptics Society, and Editor in Chief of its magazine Skeptic, which is largely devoted to investigating pseudoscientific and supernatural claims. The Skeptics Society currently has over 55,000 members...
in Scientific American
Scientific American
Scientific American is a popular science magazine. It is notable for its long history of presenting science monthly to an educated but not necessarily scientific public, through its careful attention to the clarity of its text as well as the quality of its specially commissioned color graphics...
(2%). In his book The God Delusion
The God Delusion
The God Delusion is a 2006 bestselling non-fiction book by British biologist Richard Dawkins, professorial fellow of New College, Oxford, and inaugural holder of the Charles Simonyi Chair for the Public Understanding of Science at the University of Oxford.In The God Delusion, Dawkins contends that...
, Richard Dawkins
Richard Dawkins
Clinton Richard Dawkins, FRS, FRSL , known as Richard Dawkins, is a British ethologist, evolutionary biologist and author...
includes an extensive critique of Unwin's methods.