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Is Faith Rational?

By Bruno Tomadon

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Is faith still rational?

There is a prevailing attitude that the contemporary technological world with its scientific worldview is incompatible with the faith. Faith if it was ever considered rational can no longer be accepted as such.

Is this really the case?


Faith – What is it?

Part of the problem is due to differing conceptions of what faith is. The Biblical view is that faith is the evidence for God and the Gospel i.e. the good news of how humanity can be reconciled to him. Faith has both a cognitive and relational component. There are things the Christian believes about God, but the Christian also trusts in God and his goodness towards him/her. On the other hand, a common attitude exemplified by Richard Dawkins is that faith is fideistic. It is the opposite of rational thought. Faith is what you cling to when you don’t have evidence.



Dawkins is not entirely wrong. He appeals to our intuitive sense that our beliefs should in some way be justified. There are two aspects to justification.

  1. We have certain duties and obligations in regards are beliefs. We need to do our homework, to know what and why we believe what we believe and examine opposing viewpoints. A Christian can be easily justified in this sense.

  2. The duty to believe a proposition only if there is sufficient evidence. While certainly true in some cases. Is it true in all cases?


Knowing and Showing

Rational arguments and evidence do have a role to play as well as with faith in the life of the Christian. Those roles can be summarised as:

  1. The Christian knows that Christianity is true by the inner work of the Holy Spirit

  2. The Christian shows that Christianity is true by using rational arguments and evidence.



A belief can be defined as an affirmation of, or conviction regarding, the truth of a proposition.


  • 2 + 3 = 5.

  • I see a tree.

  • Neil Armstrong walked on the moon in 1969.

  • I will win the Lotto next Saturday


Beliefs can be either:

  • Basic: not arrived at by inference or argument but in a much more immediate way

    • Memory beliefs

    • Sensory perception

    • A priori knowledge e.g. mathematical truths

  • Non Basic: arrived at by inference or argument


Properly Basic Beliefs

What types of beliefs is it appropriate to hold in the basic way?

  • Self-evident

  • Incorrigible

  • Warranted


Warranted Beliefs

Knowledge as Justified True Belief


A person S knows that p iff(if and only if)

  1. p is true;

  2. S believes that p;

  3. S is justified in believing that p.

Plantinga defines iii as warrant I.e. Beliefs have warrant sufficient for knowledge if they are produced by:

Properly functioning cognitive faculties, in an appropriate cognitive environment according to a design plan successfully aimed at truth.


A/C (Aquinas/Calvin) model

The A/C model is model that shows how belief in God can be properly basic with respect to warrant. The model posits that God has equipped individuals with a sensus divinitatis (sense of the divine) i.e. a belief producing faculty or mechanism that when it functions properly produces belief in God.

Is such a model likely? If Christianity is true, then it is very likely that God has given a sensus divinitatis or something like it because God loves us and want us to come to know him. Not everyone has the opportunity or the capacity to follow highly abstract philosophical arguments for the existence of God. If Christianity is not true, then clearly the model is not likely to be correct.

The truth of the model therefore depends on the truth of Christianity. The critic cannot claim Christianity is not rational unless he/she first shows that Christianity is not true. There are no shortcuts.

In the absence of any defeaters to belief in God faith is rational. Unlike fideism faith can in principle be falsified. It is not immune to evidence or arguments that are contrary to it.


Extended A/C Model

  • Appropriate cognitive environment

    • Sin

    • Scriptures

  • Instigation of the Holy Spirit functions as a belief producing faculty/mechanism

  • Belief in the Gospel is warranted because we have properly functioning cognitive faculties in an appropriate cognitive environment successfully aimed at truth.


Is Naturalism Rational?

Undirected Darwinian processes have equipped humanity with: properly functioning cognitive faculties in an appropriate cognitive environment according to a design plan successfully aimed at survival.

But then with me the horrid doubt always arises whether the convictions of man’s mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would any one trust in the convictions of a monkey’s mind, if there are any convictions in such a mind? – Charles Darwin

Boiled down to essentials, a nervous system enables the organism to succeed in the four F's: feeding, fleeing, fighting and reproducing…Improvements in sensorimotor control confer an evolutionary advantage: a fancier style of representing is advantageous so long as it is geared to the organism 's way of life and enhances the organism 's chances of survival. Truth, whatever that is, definitely takes the hindmost. – Patricia Churchland

The basic idea of my argument could be put (a bit crudely) as follows. First, the probability of our cognitive faculties being reliable, given naturalism and evolution, is low. (To put it a bit inaccurately but suggestively, if naturalism and evolution were both true, our cognitive faculties would very likely not be reliable.) But then according to the second premise of my argument, if I believe both naturalism and evolution, I have a defeater for my intuitive assumption that my cognitive faculties are reliable. If I have a defeater for that belief, however, then I have a defeater for any belief I

take to be produced by my cognitive faculties. That means that I have a defeater for my belief that naturalism and evolution are true. So my belief that naturalism and evolution are true gives me a defeater for that very belief; that belief shoots itself in the foot and is self-referentially incoherent; therefore I cannot rationally accept it. – Alvin Plantinga



  • It is rational to believe in God in the basic way, if there are no defeaters to belief in God.

  • There are no shortcuts. The sceptic needs to show that Christianity is false before making the claim that faith is irrational.

  • Naturalism is not rational.


Further Reading:

Religious Epistemology - William L. Craig:

Religious Epistemology - Kelly James Clark:

Knowledge and Christian Belief – Alving Plantinga:

Warranted Christian Belief – Alvin Plantinga:

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