Faith, belief and knowledge

What it is

Belief is holding something to be true. It comes in degrees, it is mostly not chosen — you cannot decide to believe it is raining — and everyone has enormous numbers of beliefs they have never examined.

Knowledge is the stronger thing. The traditional analysis, running back to Plato, is justified true belief: you know something if you believe it, it is true, and you have good reason for believing it. All three are required. A lucky guess is not knowledge; neither is a well-reasoned belief that happens to be false.

Faith is where the trouble starts, because it does not have one meaning. In ordinary religious usage across most traditions it means something closer to trust or fidelity — commitment to a person or a way of life, of the kind you might have in a spouse. In modern popular usage, particularly in argument, it means believing something without evidence, or even believing against it.

These are not variations on a theme. They are different concepts wearing one word, and an enormous amount of argument about religion consists of two people using it in different senses and each concluding the other is dishonest.

Where it came from

The justified-true-belief account of knowledge is usually traced to Plato's Theaetetus, and it held for over two thousand years until a three-page paper in 1963. Edmund Gettier constructed cases where someone has a justified true belief that is clearly not knowledge — where the justification is good, the belief is true, but the two are connected only by luck. Imagine looking at a stopped clock at exactly the moment it happens to show the right time. Justified, true, and yet you do not know. Sixty years of proposed repairs have followed and none commands consensus. Three pages broke the definition and nobody has fixed it.

"Faith" carries its ambiguity from its sources. The Hebrew emunah is built on a root meaning firmness or steadfastness — closer to faithfulness than to belief. The Greek pistis in the New Testament means trust or confidence, the word used for trusting a person. The Latin fides likewise. Aquinas treated faith as assent to what is not seen, but assent grounded in something, not floating free.

The "belief without evidence" definition is largely a modern polemical construction, hardened during and after the Enlightenment and repeated so often it now sits in dictionaries. Most theologians across most traditions reject it as a description of what they mean. That does not make the popular usage wrong — words mean what communities use them to mean — but it does mean an argument against that is not automatically an argument against what a believer holds.

How it is used

The sharpest historical statement of the two positions came within twenty years of each other.

W.K. Clifford's "The Ethics of Belief" (1877) argued that it is wrong, always and everywhere, to believe anything on insufficient evidence — a moral claim, not merely an intellectual one. His example is a shipowner who convinces himself his vessel is seaworthy without checking, and is guilty of the deaths when it sinks, regardless of his sincerity.

William James answered in "The Will to Believe" (1896). Some questions, he argued, are forced — you cannot abstain, because not choosing is itself a choice — living, in that both options are real for you, and momentous. For those, and only those, he claimed you may let your passional nature decide, since waiting for evidence is itself a decision with consequences.

Their exchange is still the cleanest framing available, and neither has been refuted. Clifford is right that believing carelessly can be a moral failure. James is right that some choices cannot be deferred indefinitely.

In practice the ambiguity gets exploited in both directions. A sceptic attacks faith-as- credulity; a believer defends faith-as-trust; each thinks they have engaged. A believer appeals to faith-as-trust to establish a doctrinal claim that would need faith-as-belief to carry. Watching for which sense is in play at which point in an argument resolves a startling amount of apparent disagreement.

What we can and cannot say

We can say that knowledge is harder to define than it looks, that the definition held for two millennia and broke in 1963, and that anyone speaking confidently about what does and does not count as knowledge is standing on ground philosophers regard as unsettled.

We can say that "faith" genuinely has multiple established meanings, and that quoting a dictionary does not settle which one your interlocutor holds. The productive move — and it is almost never made — is to ask.

We can say that Clifford and James mark out a real and unresolved tension, and that most people live somewhere between them without noticing. Almost nobody applies Clifford's standard consistently; doing so would mean suspending judgement on most of what makes an ordinary life navigable, including trust in other people.

We cannot say which of them is right, and this site will not try to. What it will do is use the words carefully: belief for holding-true, faith flagged for which sense is meant, and knowledge sparingly, because it claims more than most of this territory can support.

Further reading

• Edmund Gettier, "Is Justified True Belief Knowledge?" (1963) — three pages, freely available, and worth reading purely as a demonstration of how much damage brevity can do.
• W.K. Clifford, "The Ethics of Belief" (1877) and William James, "The Will to Believe" (1896) — read as a pair, in that order. Neither works as well alone.