I have long admired Nick Trakakis's work as a philosopher and I was deeply impressed by his eloquent farewell to Christianity.

He has raised a whole cluster of objections to Christianity. Without getting into all of the details - especially since I agree with so many of his complaints - I want to challenge one of the central ideas of his essay: the claim that religious faith is incompatible with philosophy.

At the start of his Nicomachean Ethics , Aristotle observes that moral action does not arise from moral deliberation. If you want to think clearly about virtue, you first need a virtuous disposition formed by good habits.

Aristotle drily remarks that the endless ethical debate of some philosophers is really just a sophisticated way of doing nothing. You become virtuous by acting virtuously. Once that has happened, you will also be able to understand virtue and to think philosophically about it. But if you try to start with philosophy, you will never get anywhere.

The second-century Christian teacher, Clement of Alexandria, has a similar view of the priority of acting over reasoning. Clement had travelled the world and had studied philosophy under the best teachers he could find, before finally converting to Christianity.

In a charming and poetic pamphlet called the Exhortation to the Greeks , he tried to explain his new-found faith to his cultured Hellenistic friends. Clement tells his friends that they do not first need to comprehend all the theological complexities of the Christian faith. What they need first of all is a change of disposition. The first step is to attach oneself to Christ and to start following his way. Thinking philosophically about faith comes later.

In a typically affable illustration (he is the most affable of all the church fathers), Clement explains the point by comparing religious conversion to getting drunk at a party:

"Let me give you an illustration. You might have some doubt about whether it's right for a person to get drunk. But it's your practice to get drunk before considering the question. Or in the case of self-indulgence, you don't first make a careful examination: you hurry to indulge. Only when divine things are in question do you first inquire ... Put faith in us, just as you do in drunkenness, that you may sober up! Put faith in us, just as you do in self-indulgence, that you may live!"

This is not to suggest that the Christian faith is irrational. Clement, who still thought of himself as a Greek philosopher, was not advising his friends to abandon reason. He was inviting them to undergo a change of disposition, to adopt an attitude of basic trust. Once this has happened, they will "sober up" and will start to notice that the world makes a great deal of sense when it is seen through the eyes of faith. Faith can lead to philosophy but cannot be founded on it.

Clement offhandedly assures his friends that he actually has "an abundance of persuasive arguments" about Christ, but these are for people who have already begun to "contemplate this clear faith in the virtues" - that is, to experience the way of life initiated by faith.

It is the same as in Aristotle. Some things can be understood by reason alone - geometry, for example, and the laws of logic. But there are other things that cannot be understood until they have already been put into practice - language, for example, as well as virtue and religious faith.

In the late fourth century, the North African teacher Augustine pushed this argument a bit further. In a little book on The Advantage of Believing , Augustine explained that everything in society ultimately rests on a foundation of trust:

"If it's wrong to believe something we do not know, I'd like to know how children can obey their parents and return their love and respect without believing they are their parents. There's no way this could be known by reason. We have a belief about our father based on the word of our mother ... But we do believe, without any hesitation, things that we admit we can't really know ... We could give lots of examples to show that nothing in human society would be stable if we decided not to believe anything except the things that can be held with absolute certainty."

Augustine had tremendous confidence in the power of philosophical reasoning. But he thought such reasoning has to start from somewhere. There are things you first have to accept without any proof, otherwise you will never even be able to get started. Our social relationships are possible only within an environment of basic trust. In the same way, Augustine argued that philosophical reasoning arises within what might be called a posture of basic trust towards reality.

Nick Trakakis is worried that religious faith gets in the way of a philosopher's search for truth. But how do we know that truth is desirable? Why do we assume that truth is better than falsehood? These are the questions that Nietzsche raised in Beyond Good and Evil (1886). He pointed out that the whole philosophical tradition has been founded on a premise of religious trust. Philosophers can't demonstrate that truth is better than falsehood. They accept this on trust in order to get the reasoning process started. They are willing to assume that truth is a good thing. But Nietzsche slyly asks, "Why not rather untruth?"

Why not? And, to return to Augustine's example, why not encourage children to question who their parents really are? The simplest answer would be that nobody wants to live in a world like that. It would obliterate society; we would never get anywhere. In a similar way, it is clear that Nick does not want to live in a world where untruth is better than truth. But if that is the case, his reasoning as a philosopher will have to take certain things on trust.

That is not the same as having religious faith. But it shows that faith - adopting an attitude of basic trust - is the friend, and not the enemy, of philosophy. As the fourth-century preacher Gregory of Nazianzus put it, "Faith is what gives fullness to our reasoning."

Benjamin Myers is lecturer in systematic theology at Charles Sturt University's School of Theology. He is author of Christ the Stranger: The Theology of Rowan Williams and Salvation in My Pocket: Fragments of Faith and Theology. He writes at the popular blog Faith and Theology.