Faith Is Rational Without Evidence Debate: Challenger’s Opening

Debate structure

  1. Justin’s Opening
  2. Phil’s Rebuttal
  3. Justin’s Rejoinder
  4. Phil’s Opening (this post)
  5. Justin’s Rebuttal
  6. Phil’s Rejoinder

    NOTE: It appears that as of Feb 12, 2011, Justin’s blog is off-line.


Faith, as belief in an absence of sufficient evidence, is always irrational. This fact has two corollaries.

  1. The rational mind does not require faith.
    There are no necessary unwarranted beliefs in the rational mind. There is evidential warrant all the way back to foundational beliefs. Faith is at no time necessarily employed by the rational mind.
  2. Those who employ faith do so out of irrationality.
    Faith is both definitionally and pragmatically irrational, and is detrimental to the honest seeker of truth. Faith has no place in the rational mind.

I will rigorously demonstrate the corollaries above after defining related terms and assessing foundational notions associated with belief.



  • Rational Belief: A degree of belief that maps to a corresponding degree of evidence, either empirical or logical.
  • Faith: A degree of belief that does not correspond to the degree of evidence available. For example, Jesus blessed those who believed more with less evidence.
  • Evidence: What increases the probability of the truth of a given proposition against alternative propositions, and consequently, increases the epistemic warrant for a belief through the heuristics of science including observation, induction, parsimony, and other heuristics of epistemic inquiry that result in beliefs with predicative power and logical cohesion.
  • Reason: The logical operations of the mind on constituents of evidence to arrive at logical conclusions.

The nature of rational belief

To establish a foundational understanding of belief, I want to first argue the following.

Rational belief is a degree of belief that maps to the degree of evidence.

Belief is usually not discrete; most propositions are not either certainly true or certainly false. While the referent of the proposition does have a discrete truth value, the belief in the proposition is held by a mind, an epistemic agent that does not usually have access to the entirety of the evidence that warrants certainty.

Why then do so many humans quickly categorize propositions into certainly true or certainly false? This is due to our emotional composition. Humans find it difficult to reserve judgment where there is not enough evidence. We have an emotional need to “know”, and an emotional need to show that we “know”. Other than propositions on the internal mental states of the epistemic agent, there are few propositions that the epistemic agent can assign a truth value with full certainty. Don’t read this to mean that there are not propositions that we can hold with extremely high certainty. But the propositions we encounter in our normal human lives ought to fall on a regular bell curve of degree of belief.

Here are a few terms that represent this degree-of-belief continuum.

  • I am certain that X.
  • I strongly believe that X.
  • I tend to believe that X.
  • I am uncertain about X.
  • I tend not to believe that X.
  • I strongly disbelieve X.
  • I am certain that not X.

So what it is that constrains belief? It is objective evidence. Objective evidence provides warrant for our beliefs and disbelief. A belief that does not map to the evidence available to the epistemic agent is an irrational belief.

Consider the following demonstration of a clear continuum of evidence requiring a corresponding continuum of belief.

George comes up to you one day and claims to be able to inerrantly predict the outcome of any coin toss. You set up an experiment in which the toss is truly random, and let George begin to substantiate his claim. The chart below shows a smooth linear accumulation of evidence for George’s claim upon each consecutive correct prediction. Note that, in this simple example, for each consecutive correct prediction, the evidence builds linearly. There is no demarcation between “sufficient” evidence and “insufficient” evidence. The evidence at every point on the line provides only an increasing probability between 0 and 1 on the claim. What does this tell us about warranted belief?

If belief is to be warranted, it must map to the evidence. This may not very emotionally satisfying, but this is the obligation of the rational mind. The chart on the right illustrates the human predisposition towards emotional belief or disbelief. Note that the common human employment of belief/disbelief does not very well map to the evidence, and is therefore unwarranted. The epistemic agent is obligated to restrict the degree of belief to the degree of evidence. As evidence accumulates gradually, so also warranted belief increases gradually. It is in no way binary or discrete. To the degree that the evidence is available for a given proposition, to this degree must belief follow if we are to claim it is warranted and rational.

So the degree of belief must be commensurate to the degree of evidence available to the epistemic agent. A degree of belief that does not parallel the degree of evidence is irrational.

The foundation of rational belief

It has been suggested by some who consider faith a virtue that all epistemic agents must employ faith at some level. It is claimed that, while we can find evidence that warrants our beliefs at the level of phenomena in a material world, we can never find the evidence that would warrant more fundamental beliefs such as the belief in non-solipsistic reality and the primacy of logic. Let’s take a closer look at this tu quoque claim.

Beliefs are, indeed, based on more foundational beliefs. There is a regression of dependent beliefs all the way to these more foundational beliefs that themselves need warrant. What is the warrant behind these foundational beliefs? I’ll discuss this question of warrant as pertains to two foundational beliefs that my debate opponent considers tantamount to faith.

  1. The first is the belief that reality maps directly to what is apparent. The apparent entities and relations in question include the following.

    a. We exist in material bodies rather than being brains in a vat.
    b. Our memories reflect a real progression in an objective realm of time.
    c. We freely guide our thoughts rather than them being directed by an additional entity.

    One famous argument is that we have no way to determine whether our existential context is what it seems, or whether there is an evil demon distorting our thoughts, and thereby preventing us from having any way to assign a higher probability to the simple notion that reality maps directly to what is apparent than to this evil demon.

    Note that we don’t need to assign certainty to the proposition. We only need to assess the proposition as more probable. Can we do this honestly? Yes. Fundamental mathematical parsimony requires that we, in the absence of any empirical evidence, consider the less complex of any 2 propositions most probable.

    Any mind, even one operating logically without sensory input, can perceive that the more entities, qualities and relations that are admitted to an ontology, the more complex the final ontology. The more complex the proposed ontology, the greater the probability of logical or epistemic incoherence. The mind of an epistemic agent can mathematically discern that any proposed reality that contains a larger number of structural nodes (n+1) than the apparent reality (n) contains more complexity that results in a greater chance of logical contradiction or existential incompatibility, and is therefore less probable than the more parsimonious apparent one. This is the evidence that that warrants the epistemic agent’s belief in the more parsimonious ontology. Though intuitively true, let’s elaborate on this a bit.

    With every additional entity, quality and relation, there is an exponential increase in the number of structural nodes in the ontology. Accompanying this increase in structural nodes is the higher probability of logical contradiction or existential incompatibility found within the corollaries of the original proposition. The rational mind, apart from the need to instantiate the variables and thereby independent of induction or empirical fact, can perceive that, as the number of variables increases in any particular claim, the chance of incoherency in the form of logical contradiction or existential incompatibility also increases. This breaks the evidential symmetry between the two notions that 1) the perceived world is real and that 2) the world is a product of an evil demon, and the epistemic agent can then rationally extend a greater degree of belief to the notion that the perceived world is real. Faith is not rational here, nor is it ever.

    A simple illustration of this foundational mathematical parsimony can be found in a thought experiment. Which is more probable; that an evil demon is manipulating your perception, or that a greater evil demon is manipulating the actions of a lesser evil demon who believes he is freely manipulating your perception? And this is positing only 2 demons. Who would claim that a proposed reality in which a longer chain of hundreds of successive deceptive demons exists has the same probability as a proposed world that corresponds to the world that we immediately perceive? As entities, qualities and relations increase in a given proposition, so does the mathematical improbability of its truth, all things being equal. This mathematical parsimony does not require the inductively acquired validation of parsimony found in human experience, and for this reason, it is foundational. This foundational mathematical parsimony provides a legitimate boundary to any would-be infinite regress of epistemic dependencies.

    Here I want to make an important point.

    I choose to act as if X.

    Pragmatic belief-free choices are not irrational.

    The pragmatic choice of one of 2 equally substantiated/unsubstantiated possible truths is not irrational. Even if the evil demon illusion and the reality of perception propositions were equally substantiated or unsubstantiated, it would not be irrational to choose the reality of perception. It is a belief-free choice. If I come to a fork in the road, and have no evidence where either path leads,

    I believe X.

    Irrational epistemic commitment in the absence of evidence.

    I am not irrational in choosing either. If I have equal evidence for any two propositions, choosing one out of pragmatism does not constitute irrationality. Anyone accusing as irrational individuals who choose

    I believe Y.

    Irrational epistemic commitment contrary to acquired evidence.

    to live life as if their perceptions were true must show that the evil demon proposition is more probable than the proposition that reality maps to our perceptions. Where there is merely choice without epistemic commitment, there is no irrationality. It would be irrational to believe with full certainty that the reality of my perception was true and that the evil demon proposition was false if there was equal evidence for the evil demon, but as I have shown above, this is clearly not so due to fundamental mathematical parsimony. However, the epistemic agent who believes in an evil demon (and I have yet to meet someone who does) and understands foundational mathematical parsimony would believe in the evil demon irrationally.
  2. The only assumption that remains to be grounded is that of logic. Our foundational mathematical parsimony employed above is a logical principle. But what grounds logic itself?

    Here’s a preliminary question; How do we know thought works?
    This question is silly. The very fact that we can think about thinking demonstrates that thought works.

    Now imagine someone claiming that the previous statement is an invalid proof of the efficacy of thinking because it contains a circularity. This claim of circularity would be absurd. Within the very circularity of the proposition is the validation of the proposition! Would you say the sentence “I am able to construct a sentence” is an invalid proof of the author’s ability to construct a sentence due to its circularity? On the contrary! It is a salient demonstration of the very ability in question! In like manner, the circularity in the statement “the fact that we can think about thinking demonstrates that thought works” is not only legitimate, but a irrefutable demonstration of thinking.

    Now we move to the next question. How far would our thoughts get if they were not inextricably entwined with logic? They would not even get off the ground. Where there is no logical coherence, there is no thought. Where there is no thought, there is no subjectivity. Where there is no subjectivity, there is no subject. Without logical coherence, we would not exist as a cognitive being. Working logic is required for conscious existence. Thought is an instantiation of logic. Without logic, there would be no mental content. We know logic works because we can logically ponder whether logic works. There is as much illegal circularly in this as saying we know thought works because we can think about whether thought works; that is, none. Logic is the fundamental constituent of thought, and the very fact that we think is the evidence that logic works. Every thought at every given moment is testimony to the efficacy of logic. Logic is the foundation of existence. I have no faith in the efficacy of logic. I have constantly confirming evidence that logic works beginning with the smallest flickering thoughts of self-awareness. It is inconceivable how illogic could render any reality to a mind. The simple act of thinking provides the evidence that logic works, while relegating any value of illogic to the inconceivable. This asymmetry between a substantiated logic and an inconceivable illogic is sufficient evidence to warrant my belief that the logic I perceive in reality is not merely apparent.

So, there is no infinite regress of dependent assumptions resulting at a need for faith. Rational belief is grounded in foundational mathematical and logical parsimony, and results in a clear warrant for belief that our apparent reality reflects an objective reality. Faith, in contrast, remains in the realm of irrationality.

The measure of belief

The measure of post-foundational beliefs is the degree to which these beliefs align to the degree of evidence for the apparent objective reality we are warranted in believing as established above. The measure of belief is not the emotional comfort nor the sense of purpose a belief might offer. Belief must stand with its back against the cold ruler of objectivity. Subjective concerns only serve to distort the measurement. It requires intellectual honestly and focused rigor to restrain our beliefs to this objective standard of our empirically-assessed reality. The reward is an objectively-purified ontology that will provide far superior explanatory and predictive powers for optimally living our subjective lives.

The assessment of belief

Now that we have identified this objective standard against which beliefs are to be measured, we must determine the process that leads to an accurate measurement.

The approximation to objective truth of any proposition or coherent set of interdependent propositions (ideology) is tested by its efficacy. Does the ideology work as advertised?

Effects that the ideology or proposition in question entail are tested through experimentation. The design of an appropriate experiment is guided by the objective filter of the proven heuristics of scientific methodology. An effect expected within a given ideology that is confirmed by experimentation constitutes evidence for that ideology, and the absence of of an expected effect is evidence of the failure of that ideology. Contrary to a popular mindless slogan, absence of evidence is indeed evidence of absence when the thing absent is an effect predicted by the ideology or proposition in question.

An ideology, theory or proposition that has been sufficiently vetted by experimentation is then applied to real-world applications. The success of the dependent technology is even greater evidence for the veracity of the underlying ideology, theory or proposition.

Here are just a few examples where beliefs are given warrant the the evidence emergent of scientific testing and real-world application.

  • Does an alchemist believe that a certain mixture of compounds will produce gold. To the degree that those compounds produce gold, to that degree his belief is warranted.
  • Does an aeronautic engineer believe that there is a feature of turbulence hitherto undiscovered? To the degree that a wing designed to take advantage of that new feature works, to that degree his belief is warranted.
  • Did Einstein claim that gravity withing the space/time continuum would bend light? To the degree that observations confirm that claim (and they have), to this degree belief in the claim is warranted.
  • Does someone’s god claim to always heal those the inflicted who are prayed over? To the degree that prayed-for individuals recover independent of other confounding factors, to this degree we are warranted in entertaining the existence of such a god.
  • Does someone claim to be a psychic? To the degree that they foretell details about the future above chance, to this degree we are warranted in accepting their claim as true.
  • Did the engineers of Apollo 11 claim the theories of force, motion and gravity under-girding propulsion and orbits were well-established? To the degree that their spacecraft performed as expected, to this degree we are warranted in accepting the theories under-girding their technological successes as true.

Any belief that does not have warrant is irrational. Warrant is found in evidence of efficacy through experimentation and application.

Here, I’d like to address a slight-of-hand some less-than-honorable individuals have performed. They claim that the confidence of the scientifically under-informed on the authority of expert scientists for a given phenomenon constitutes “faith”. It is not. The track record of the scientific community or an individual scientist constitutes evidence for their reliability. My degree of confidence in what a group of scientists affirm ought to match the record of success for that particular group of scientists. This disallows absolute confidence, but also unwarranted disbelief. Whenever my degree of confidence matches the degree of success of the authority, I am in no way employing “faith”. My belief is warranted through my inductive assessment of their track record. Anyone who claims this is “faith” is either dishonest or has not even a rudimentary understanding of induction and its role in objective science.

This ends my treatment of the first corollary; The rational mind does not require faith. Where there is evidence for a belief, there is warrant for that belief. Where the degree of warrant matches the degree of belief, there the belief is rational. Those who suggest that there is some point at which even the most scientific mind must employ faith are either ill-informed or dishonest. Faith is always irrational.

The definitional failure of faith

Faith is, from the start, a bankrupt and absurd concept. If the purpose of faith is to provide emotional comfort, then faith works. However, most who promote faith claim it maps to objective truth rather than simply alleviating emotions. We are going to assume that my opponent believes that faith maps to objective truth. If he does not, then we have no argument as I also believe false belief produces comfort. I contend, in no uncertain terms, that faith does not map to objective truth.

My opponent is a Christian theist, so we will pull our definition of faith from the Christian “word of truth” under the assumption he will necessarily agree with this definition.

Then Jesus told him, “Because you have seen me, you have believed; blessed are those who have not seen and yet have believed.”
(John 20:29)
λέγει αὐτῷ ὁ Ἰησοῦς ὅτι ἑώρακας με πεπίστευκας; μακάριοι οἱ μὴ ἰδόντες καὶ πιστεύσαντες.

Warranted belief follows the evidence. Jesus is here actually promoting the opposite. Promoting more belief where there is less evidence is antithetical to rational belief. Warranted belief is always weaker when there is less evidence, and is certainly not the inverse promoted here by Jesus. Faith is, in its very definition, irrational and incoherent.

Here is another biblical example of the irrationality of faith. A man with a demon-possessed son approaches Jesus.

“But if you can do anything, take pity on us and help us.” “‘If you can’?” said Jesus. “Everything is possible for him who believes.” Immediately the boy’s father exclaimed, “I do believe; help me overcome my unbelief!”
(Mark 9:22-24)
ἀλλ’ εἴ τι δύνῃ βοήθησον ἡμῖν σπλαγχνισθεὶς ἐφ’ ἡμᾶς. ὁ δὲ Ἰησοῦς εἶπεν αὐτῷ· τὸ εἰ δύνῃ πάντα δυνατὰ τῷ πιστεύοντι. εὐθὺς κράξας ὁ πατὴρ τοῦ παιδίου ἔλεγεν· πιστεύω· βοήθει μου τῇ ἀπιστίᾳ.

Incredibly, instead of asking for more evidence, the father of the sick boy claims he believes, then actually asks the “authority” in question to help him overcome his doubt! The absurdity of invoking the authority in question to alleviate doubt in that very authority is starkly clear. A noble request for confirming evidence is not made, but rather a request for the one making the claim to magically remove the lingering doubts. This is truly faith, and is truly absurd.

The incoherence of this man’s faith is easy to tease out with a simple thought experiment. Suppose that the demon-possessed boy’s father had first met a witch who also claimed to be able to heal his son. Suppose that an identical verbal exchange had taken place. What evidence did the man have in his possession that would have prevented him from also telling the witch “I do believe; help me overcome my unbelief!”?

Today, young children all around the world are encouraged by their theistic parents to place faith in the local religion. Doubt is disparaged as “evil”…until that child is old enough to contemplate the claims of rival religions. Then doubt is encouraged, and faith in the rival religion is tagged “evil”. Faith is applied contextually instead of universally.

As long as the context is social in which the group is attempting to encourage adoption of their unsubstantiated claims, faith is strongly encouraged, and doubt is proclaimed to be “evil”.

Take heed brethren lest there be in any of you an evil heart of unbelief in departing from the living God.
(Hebrews 3:12)
Βλέπετε, ἀδελφοί, μήποτε ἐσται ἔν τινι ὑμῶν καρδία πονηρὰ ἀπιστίας ἐν τῷ ἀποστῆναι ἀπὸ θεοῦ ζῶντος,

Whatever faith is, it is certainly not a rational acceptance of that for which there is evidence. Here doubt is called “evil”. There is no talk of evidence. And evidence is the only thing that gives warrant to beliefs. Those who promote this ridiculous biblical notion of faith can, in no way, claim to have approximating objective truth as their goal. Faith is encouraged locally, yet anathema globally. Doubt is anathema locally, but encouraged globally. Biblical faith is far from a consistent universal principle, incoherently and inconsistently paints belief and disbelief with brushes of “evil” and “righteousness” depending on the context, and runs antithetical to the evidential warrant that allows science to approximate objective truth as demonstrated through predictive power and successful application.

Biblical faith dies in the starting block of its definition.

The pragmatic failure of faith

The epistemic warrant for any ideology, theory or proposition is measured against its proximity to objective reality. It’s proximity to objective reality is assessed by the success of its predictions and application.

Biblical faith has failed to provide any verified predictive power, and the results of it’s application run counter to its claims.

There used to be a time when Christians loudly boasted that faith in Jesus brought with it a divine power to overcome “sin”, and a promise of miraculous divine intervention on behalf of believers. After the introduction of statistical tools, access to global data, and an understanding of the placebo effect, these boasters have unsurprisingly clammed up. Now, most Christians who maintain that there is efficacy in faith take one of the following approaches.

  1. Some Christians have simply reinterpreted the bible to reduce the number of the claims to a few that are out of the reach of the scrutiny and rigor of an objective science.
    Human behaviors affirmed to be demon-possession by theists in centuries past are now labeled epilepsy or are given another material explanation, yet theists maintain that demons are still out there somewhere conveniently beyond the range of scientific validation.
    The prayer of faith that used to save the sick is now reinterpreted in such a way that the “power of God” is identical to the absence of any god. Biblical claims are insulated by a scriptural vagueness that allows for a reinterpretation quite disparate of the interpretations of the faithful centuries ago, yet an infidel’s accusation of evasive hermeneutics is shrugged aside as the spiritually blind commentary of faithless fools.

    Where are the bold claims? Does your god provide you with a “holy spirit” that keeps believers behaviorally superior to infidels? Then compare a substantial group of believers to a group of Japanese infidels on various axes such as crime, divorce and obesity. Any ideology that predicts superior behavior among its constituents, yet yields inferior behavior, even against its own standard of righteous behavior, is false. Any ideology that predicts superior behavior among its constituents, yet yields equal behavior is also false. The evidence for the veracity of an ideology is in its predictive power. Where is the predictive power in Christianity. Provide this to the scientific community for verification. Does prayer work? Define how it works and submit it to the scrutiny of science. The vague assurances of faith-mongers in the efficacy of their faith dissipates under the lamp of scientific scrutiny. Enough fluff. Evidence is the only warrant for belief. Faith, both definitionally and pragmatically fails.

  2. Others faith-mongers simply suggest that, the evidence is right in front of our faces, yet unbelievers cannot perceive the evidence since it can only be “spiritually” discerned.
    They don’t trouble themselves with spotlighting the evidence; they simply affirm it is there. For them, the “spiritual” blindness of doubters is the reason these doubters reject a salvific Jesus, for this is what the “word of truth” has affirmed. I have no time for these pompous promoters of an incoherent faith based on invisible evidence. There can be no dialog with those who tag others as spiritually “blind”, thus invoking the certainty of the very ontology in question. Leave them to suffer the curse of an incoherent and credulous mind.

Thus my second corollary is demonstrated; those who employ faith do so out of irrationality.


Warranted belief maps to the degree of the evidence available. There are no exceptions. There is no excuse for faith.

I have shown that the rational mind has no need to resort to faith at any point in the chain of epistemic dependencies. Solipsism is defeated by the evidence emerging from foundational mathematical parsimony, and logic is evidentially grounded in foundational logical parsimony.

If Justin can provide a single example of an epistemic commitment I must make that is absent of evidence, he will have made his point. He was asked to do this in my rebuttal of his opening argument, and failed to do so. An example of an actual epistemic commitment does not mean vague theoretical commentary. Justin will have to provide an actual belief I must hold to sustain my world-view that is not accompanied by evidence. Only then can he claim I must also employ faith.

I have also demonstrated that faith, as biblically defined, fails both definitionally and pragmatically.

Faith will always fail as a path to truth. It has neither a coherent definition nor can it be applied universally. Its promotion depends on whether its object is revered by the community, and it is discouraged and tagged as “evil” where it does not. It is a deleterious weapon wielded by local faith-mongers who wish to insulate the credulous in their community from healthy rational skepticism, and in so doing, condemn them to local myth and falsehoods. Ironically, this is the argument of every theist against the faith-mongering of every religion but their own.

Faith has produced no scientifically verified demonstration of an efficacy that exceeds material expectations. It has been relegated to distant domains of speculation far removed from the scrutiny of scientific inquiry. It has been reduced to an ephemeral theory of nothing that conveniently maps to material expectations. Its vague scriptural foundation has been reinterpreted time and and time again over the centuries to accommodate the ever-growing success of scientific knowledge. It has no successes of its own, nor can it. It has no redeeming value as a concept. It is an absurdity, incoherent in definition and impotent in practice. It has no place in a rational mind.

I strongly suggest that, if there is to be any real argument from Justin in defense of faith, it will come in the form of clear and cogent real-world examples where faith is shown to have provided a non-evidential route to objective truth. In the absence of such examples, faith is indistinguishable from theoretical impotent fluff.

Metadebate comments

  • In his opening statement, my opponent suggested that the implications of my position would damage commonly-held beliefs of atheists. This debate is about the truth of the proposition, not about its implication. A discussion of the implications of a position is inappropriate in a debate about the truth of a proposition. Objective truth is distinct from its implications, and its implications on a third party’s ideology has nothing to add to a discussion about its veracity.
  • In Justin’s rejoinder, he responded to my argument by simply suggesting I was “glossing over 400 years of philosophy”. When I make an argument, it is mine. I won’t simply tell you to refer to and argue with Descarte. If I ignore valid arguments made centuries ago, I do so to my own peril since you can provide those arguments in your own words. If you have a response to the argument, make it. Feel free to borrow from other minds, but don’t invoke the history of philosophy as a substitute for your own argumentation.


4 thoughts on “Faith Is Rational Without Evidence Debate: Challenger’s Opening

  1. Bolgoarth says:

    A very rigorous and well-laid out argument, Phil. Kudos.

  2. It appears that Justin’s blog is now off-line.

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