The reasonableness of belief that God exists is a focal issue in the Philosophy of Religion. The reasonableness of theism is therefore as much a matter of the reasonableness of an epistemology of revelation as it is of a metaphysics of perfect being. Being in established relationships of friendship with others, too, can also require commitment to continue to trust them even in the face of evidence that, otherwise, would make it reasonable to believe them unworthy of trust. Similarly, accounts of theistic faith will be open to critique when they make assumptions about the mechanisms of revelation. The question of how God may be expected to make himself known has gained prominence through recent discussion of the argument for atheism from ‘divine hiddenness’ (Schellenberg 1993; Howard-Snyder and Moser 2002). That argument holds that a loving God would make his existence clear to the non-resistant-but this claim is open to question.

When one takes it to be true in practical reasoning that someone will prove trustworthy, that mental act may be more or less epistemically rational: it would break the evidentialist norm to employ in a decision-theoretic calculation a credence that does not match one’s available evidence. Yet, affording high credence to a person’s trustworthiness may still be epistemically rational given wider available evidence of, for example, the person’s past friendliness and trustworthiness in other matters, or, if the person is a stranger, of our shared social experience that trusting others generally elicits a trustworthy response. In a life-threatening situation, for example, it may be rational to trust unlikely rescuers if they are the only ones available. The answer seems clear: reasonable trust is practically rational trust. The question remains how accepting this gift could be epistemically rational. The exercise of practical reasoning does include mental acts which are epistemically evaluable, however. It is far too easy to focus on individual acts of terrorism and extremism, and ignore the global patterns in such violence. But there’s heavy material included in the book too, including quantum physics that has kept producers and directors at bay so far. However, things go awry when the leader of the gang hides the diamonds just before being arrested.

Islam, being religion of nature, comprehends that human beings are born with variable favors. There are significant differences, however, between the trusting involved in theistic faith and that involved in interpersonal trust. Attempting to settle that concern by meeting the evidential requirement leads to circularity: theological truths are to be accepted on divine authority, yet the truth that there is such an authority (historically mediated as the relevant tradition maintains) is amongst those very truths that are to be accepted on divine authority-indeed, it is the crucial one. Aquinas’s model of faith thus shares with the Reformed epistemologist model the problem that it leaves unanswered the reflective believer’s concern about entitlement. What is salient includes belief or some related sort of affirmation, not just that God exists but associated content such as that this God exists, the God who is revealed thus and so (in great historical acts, in prophets, in scriptures, in wisdom handed down, etc.).

The question of when one may rationally trust another may thus be resolved by a decision-theoretic calculation, factoring in the extent to which one’s evidence supports the potential trustee’s trustworthiness and the utilities of the possible outcomes, given one’s intended aims. But if, as is plausible, good reason to trust requires sufficient evidence of the trustee’s trustworthiness, reasonable trust appears both to have its venturesomeness diminished and, at the same time, to become more difficult to achieve than we normally suppose. If, moreover, faith of the religious kind is itself a type of trust, then we may expect our understanding of religious faith to profit from an analysis of trust in general. Most importantly, however, Aquinas says that assent is given to the propositional articles of faith because their truth is revealed by God, and on the authority of the putative source of this revelation. Propositional articulations of what is revealed may still be essential, but they need to be accepted as at a remove from the object of revelation itself, and therefore as limited. The development of propositional articulations expressing the nature and will of the self-revealing God-the doctrines of ‘the Faith’-will, of course, be understood as a process under providential grace.