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Agnosticism and Atheism

Rand, David

Absolute uncertainty is no more tenable
than absolute certainty

A discussion of the definitions of agnosticism and atheism, and several variants of them.
This is the English translation of a text which appears in the anthology Là-haut, il n'y a rien ("Up Above, There is Nothing") compiled by Normand Baillargeon.


Varieties of Unbelief

Among non-believers, it is apparently more common to label onself agnostic rather than openly atheist. Polls of religious affiliation usually make little distinction among the various levels of non-belief. Even if they did, for their results to be useful we would first need clear definitions of the terms used in the questions. It is therefore important to reflect a bit on the meanings of these two labels. What does it mean to be an "agnostic" or an "atheist"?

First of all, let us start from the principle that the generic meaning of "atheism" is "a-theism", that is, "without theism", where the "a" indicates absence. Theism is generally defined as the belief in a personal god, creator of the universe; this god, although considered to be distinct from the natural world, nevertheless intervenes in this world, in particular in human affairs. (This article does not discuss deism -- belief in a impersonal creator god, rejecting revelation and divine intervention -- nor does it discuss pantheism.)

This interpretation of the word "atheism" is not the only one possible. The prefix "a" can be understood as meaning negation, so that atheism would be denial of the existence of the theistic god, in other words affirmation of the non-existence of that god. But I much prefer the "absence of theism" definition of atheism because the negative formulation is basically a form of fideistic atheism (which will be discussed below).

Agnosticism, on the other hand, is a relatively modern term. It was in the late nineteenth century that Thomas H. Huxley, orator and celebrated proponent of Darwinism, conceived the word "Agnosticism" (the capital "A" is his) to designate the attitude of healthy scepticism which he advocated towards preconceived ideas and baseless hypotheses. It is significant that the root of the term "agnostic" is "gnostic", indicating Huxley's rejection of mystical religion.

Faith and Reason

Table 1 is an attempt to place these concepts in context, illustrating the similarities and differences among them. This tabular presentation is inevitably simplistic, as the nuances of belief and unbelief cannot easily be fit into little boxes, but it is a guide. Further, it does not take into account either deism or pantheism.

These various forms of belief and unbelief can be based on faith, motivated by observation and reason, or assimilated passively and naively from one's social milieu. This diversity is represented by the three columns A, B and C, placing faith and reason at the ends of the spectrum. Theism is based primarily on faith (box A3), but it is often adopted simply out of conformism (B3). Theists sometimes attempt to establish their beliefs on a rational basis (C3). An example of this last approach is that of Swinburne [2] who attempts to prove, using Bayes' Theorem, that the probability of the existence of the Christian god is greater than 50 %. His arguments are far from convincing, but one has to appreciate the effort he puts into them.

The vertical axis of the table thus represents the dimension belief-vs-unbelief; by moving upwards, we distance ourselves from theism. The horizontal axis represents the dimenion faith-vs-reason; as we move to the right, we distance ourselves from fideism which is associated with absolute belief or unbelief.

Table 1
Absolute or fideist (faith-based)
Naive or practical
Rational or reasonable
Fideistic Atheism:
"I am absolutely certain that no god exists nor can exist."
Practical Atheism:
"Belief in god is of no use to me; I live my life with no thought of it."
Rational Atheism:
"I have no belief in god(s)."

Rational Agnosticism:
"I have no belief in god(s)."
Symmetric Agnosticism:
"Both the existence and the non-existence of god are equally unprovable."
Indifferent Agnosticism:
"I am neither a believer nor a nonbeliever; I guess I do not know."
Fideistic Theism:
"I have absolute faith in God, my God."
Conformist Theism:
"I believe in God like everyone else."
Rational Theism:
"The existence of God follows from observation of His creation and His works."

Absolute or Symmetric Agnosticism

The variant of agnosticism I call "symmetric", in box A2 of Table 1, gives equal weight to both belief and unbelief. When applied to theism, symmetric agnosticism begins with the lack of absolute proof either way and concludes from that observation that the existence and the non-existence of the theistic god are equally probable. Evidently this approach is not reasonable because it arbitrarily cuts down the middle, taking no account of the relative verisimilitude of each of the two hypotheses. If this form of agnosticism were applied everywhere, the absence of absolute proof would imply complete uncertainty in all endeavours, and no conclusion could every be reached, no knowledge would be possible. We arrive thus at absolute scepticism or strong relativism, an attitude of anything-goes, where nothing is true and nothing is false. This is light-years away from the agnosticism of Huxley.

Absolute certainty exists in mathematics, in pure logic... and in religious dogma. In the real world, we have to make do with knowledge which is somewhat uncertain or, at best, knowledge which is certain beyond a reasonable doubt. My last class in thermodynamics was many years ago, but if memory serves me correctly, it is not absolutely impossible for the surface of a lake to freeze over with a thick layer of ice on a summer day with 35° C. heat. But the probability of such an eventuality is so very tiny as to be negligible, and we can thus say, with reasonable certainty, that it will never happen. If we adopt an attitude of absolute scepticism and allow the existence (or not) of Jehovah to be undecidable, then we must also allow the existence (or not) of Santa Claus to be undecidable. This comparison between a god and a childish myth is not frivolous; on the contrary, it illustrates the futility of symmetric agnosticism.

The Untenability of Theism

The symmetric agnostic adopts an equivocal attitude towards theism. However, theism is untenable for a number of reasons. First of all, regardless of all the ambiguity which may be inherent in its dogmas, each theism asserts the existence of a particular personal god in a particular world with specific characteristics which are highly improbable and often contradictory. With each specific characteristic that is added to the mix (a messiah here, an angel there, etc.) the result becomes more and more implausible. The whole story rests on a set of unsupported hypotheses while, according to the famous sceptical principle of Carl Sagan and David Hume, extraordinary claims require extraordinary evidence. It is up to theists themselves, not to unbelievers, to provide some evidence of the veracity of their dogmas. Further, we know that theisms are ancient mythologies which originated in the imaginations of prescientific humans. The falsehood of theism is the only reasonable conclusion. (Note that this discussion does not consider any pragmatic value which religious practice might have, but only the truth or falsehood of religious tenets.)

Even if we set aside for a moment the extreme implausibility of its beliefs, there remains another hurdle which a theism must leap in order to reach anything resembling credibility: the question of authority. The spokepersons of each established theism speak in the name of their divinity, claiming specialized knowledge of the will of that divinity. Now, that pretention is itself highly implausible, because on what basis can we say that John-Paul II has a better knowledge of the will of the Creator than have, for example, Britney Spears or a Vietnamese peasant? The product of two infinitesimal probabilities is an even more negligible quantity.

Fideistic Atheism

Faith-based atheism (box A1) consists in rejecting theism on the basis of faith in the non-existence of god(s). It is somewhat like killing a fly with dynamite (or a nuclear device). The faith-based approach is superfluous and unnecessary. No one would bother to declare, "I have absolute faith that the earth is not flat" because the earth's non-flatless is an observed fact of which we can be reasonably certain. No need for faith. The situation is similar for the various theisms. We do not need faith to justify abandoning them.

It is interesting to note that Huxley rejected atheism, which he apparently identified with its fideistic variant. But his agnosticism, solidly anchored in column C, was anything but symmetric!

Reasonable Agnosticism and Atheism

In Table 1 the separator between boxes C1 and C2 is almost absent because, by applying a rational attitude towards theism, the atheist and the agnostic arrive at conclusions which are practically identical. Indeed, the only significant distinction between them is the label chosen by each. Both reject all theisms, and for similar reasons. Theisms are mythologies which we can assert, with reasonable certainty, to be false.

To summarize: non-fideistic agnosticism leads inexorably towards atheism. In other words, non-fideistic atheism is the result of the application of doubt to theism.

Spokespersons for the Great Beyond

A few years ago, I made the acquaintance of a charming gentleman who believed that the world of Star Trek really existed in a concrete future and that the inhabitants of that world could communicate with us by waves transmitted backwards through time, from the future to the past, arriving at what is our present. My only reaction to this delightful assertion, other than a subtle smile, was to shrug my shoulders a little to indicate that I was less than convinced. It would be different if millions of people held the same belief, and the situation would be still more worrisome if some of these believers had also convinced themselves that they could personally receive these "trekkie" transmissions and thus become spokespersons for the future, with all the authority that such a privilege would imply. This "trekkie" sect would become frankly dangerous if furthermore these spokespersons declared that the knowledge acquired from these transmissions was necessary in order to live well and that, consequently, all those outside the sect -- all "atrekkies" -- who did not pay proper heed to their transmission reports should not be trusted.

Now this is pretty much what happens with the major theisms. Millions of people have a similar belief, and this belief is based on unfounded hypotheses. Various spokespersons -- Christian, Muslim or Jewish religious authorities (or, as a polytheistic example, Hindu) -- have established themselves, and claim to speak for the hypothetical agent at the centre of this belief system. And these authorities also declare that the knowledge thus acquired is necessary in order to live morally. It is only in recent history that some of the more moderate religious authorities have avoided making this last declaration too often or too openly.

Although incapable of proving that my trekkie friend was wrong, I nevertheless decided that his hypothesis was false. This falsehood I accepted as being reasonably certain, for I estimated that the probability of his being right was infinitesimal, that is, negligible. I could always adapt or modify my conclusion in the (extremely improbable) eventuality that new data arrived throwing doubt on it. I did not say to myself -- as a symmetric agnostic would say -- "Oh, it is undecidable, for I have neither proof, nor proof of the contrary." But that is precisely what many critics of atheism propose: to remain undecided when confronted with theisms, those ancient mythologies, inherited from humanity's prescientific past, which are even more implausible than my friend's "trekkianism".


Atheism is defined by contrast to theism. It is the recognition of the falsehood of theism. Words such as "atheist" and "atheism" have existed in various human languages for a very long time, because the origins of theism are very ancient. There is however, to the best of my knowledge, no word such as "anastrologist" to indicate an absence of belief in astrology. If theism were as marginal as astrology is today (unless I underestimate its importance), it would no longer be necessary to declare oneself to be an atheist, because a sort of practical atheism by default would be the norm in our society. The word "atheism" would rarely be used outside of formal academic discourse. But that day is still a long way off.


  1. Thomas Henry HUXLEY, Agnosticism and Christianity and Other Essays, Prometheus Books, Buffalo, New York, U.S.A., 1992
  2. Richard SWINBURNE, The Existence of God (Revised Edition), Clarendon Press, Oxford, 1991