How Do We Know Anything?

Why this question matters

We rely on knowledge all the time—about people, medicine, money, history, and the world around us. But how do we actually know what we think we know?

If we're going to talk seriously about science, morality, God, or any worldview, it helps to be clear on how things like evidence, reason, intuition, and experience fit together. Otherwise we risk talking past each other: one person demanding lab results, another relying on personal experience, a third appealing to logic.

In this guide, we'll look at:

1. What counts as good evidence?
2. Can we know anything with certainty?
3. How do reason, emotion, and intuition work together?
4. Can we trust our senses and minds at all?
5. What do we mean by "faith," and is it just believing without evidence?
6. Are miracles ever believable?

The goal is not to settle every debate, but to clarify the tools we're using when we say "I know" or "you can't know that."

1. What counts as good evidence?

1.1 Different kinds of evidence

"Evidence" is not just lab results. In practice, we rely on several kinds:

• Scientific evidence – repeatable observations, experiments, measurements.
• Historical evidence – documents, artifacts, testimony, and patterns from the past.
• Logical evidence – what follows from definitions, patterns, and arguments.
• Experiential evidence – what we directly experience in our own lives (pain, joy, conscience, beauty, inner awareness).

Each plays a role:

• You don't run a randomized controlled trial to see whether your friend showed up for dinner; you use memory, testimony, and common sense.
• You don't decide whether a medicine works based only on intuition; you look for controlled studies.
• You don't demand a lab test to see whether a mathematical proof is valid; you follow the reasoning.

A mature approach doesn't elevate one type of evidence as the only valid kind. Instead, it asks: which kinds of evidence are appropriate for this particular question?

1.2 "Only science counts" – and why that's a belief too

Some people say, "The only things we can really know are what science can measure." That statement itself is not a scientific finding; it's a philosophical claim about knowledge.

• You cannot run an experiment to prove "only experimentally verifiable things can be known."
• If that rule were applied to itself, it would fail its own test.

Science is powerful precisely because it restricts itself to certain kinds of questions—the measurable behavior of the physical world. Questions about meaning, morality, and ultimate reality may interact with science, but they are not simply "more physics." We still need logic, reflection, and other forms of evidence to handle them well.

2. Can we know anything with certainty?

2.1 Two extremes: total doubt vs blind confidence

One extreme says, "We can't truly know anything, so it's all opinion." The other says, "I'm absolutely certain, and no evidence could ever move me."

Both are hard to live with:

• If we never think we know anything, we can't make responsible decisions.
• If we refuse to revise our beliefs in light of new evidence, we risk stubbornness rather than conviction.

Most of life operates in between: we have beliefs with different levels of confidence.

2.2 Everyday certainty vs mathematical certainty

There's a difference between:

• Mathematical certainty – for example, basic arithmetic or simple logic.
• Practical certainty – strong enough confidence to act, even if logically we could be wrong.

We rarely demand the first category in ordinary life. We don't need proof that rises to the level of a geometry theorem to trust a pilot, sign a contract, or choose a doctor. We weigh reasons, look for warning signs, and then act.

The same applies to big questions. We may not achieve "I can't possibly be mistaken" certainty, but we can still ask what is most reasonable, given all the evidence we have.

3. How do reason, emotion, and intuition work together?

3.1 Reason: our "checking" tool

Reason helps us:

• Notice contradictions ("These two beliefs cannot both be true").
• Trace implications ("If X is true, then Y probably follows").
• Organize evidence into an argument.

Reason doesn't give us raw data; it helps us make sense of the data from senses, memory, testimony, and experience.

3.2 Emotion: helpful but not decisive

Emotions:

• Can warn us about danger or injustice.
• Can attach us strongly to beliefs that feel safe or familiar.

But feelings alone can't tell us whether a belief is true. Something can feel comforting and still be false; something can feel unsettling and still be true. Emotions are important signals, but they need to be tested alongside evidence and reasoning.

3.3 Intuition: fast judgments

Intuition is our ability to "just see" that something is off, or that a pattern is present, without conscious step‑by‑step reasoning. It's useful in many areas—chess, driving, reading people—especially when it's been shaped by good experience.

But intuition can also carry biases and blind spots. A healthy approach is:

• Pay attention to intuition.
• Then ask, "Why do I feel this?" and check it against reasons and evidence.

Knowing often involves all three—reason, emotion, intuition—working together, with reason and evidence playing the "referee."

4. Can we trust our senses and minds at all?

4.1 Radical skepticism

It's possible to ask: "What if everything I perceive is an illusion? What if my memories are unreliable? What if my mind is constantly tricking me?" Taken to an extreme, this leads to radical skepticism—doubting almost everything.

Philosophers have pointed out that:

• Total doubt is hard to live by consistently. Even the skeptic trusts their senses enough to cross the street or avoid oncoming cars.
• Trying to doubt everything typically ends up trusting some things (like logic, or the idea that doubt is meaningful) without proof.

4.2 Fallible but generally reliable

A more livable position is:

• Our senses and minds are fallible—they can be mistaken.
• But they are also generally reliable—reliable enough that we can correct errors over time.

We refine our knowledge by:

• Comparing notes with other people.
• Using instruments to extend and check our senses.
• Testing predictions against outcomes.
• Being open to revising beliefs when new evidence appears.

We don't need perfection to know anything. We need a framework where correction is possible and where we can distinguish better from worse explanations.

5. What do we mean by "faith"?

5.1 Common misunderstanding: "belief without evidence"

In everyday speech, "faith" often gets defined as "believing something without evidence" or even "believing something despite the evidence." Under that definition, faith and knowledge are enemies.

But in many traditions, "faith" is closer to trust in a person or claim, based on some perceived reliability or evidence, not a leap into the dark for no reason.

For example:

• You trust a doctor because of their training, track record, and how they've helped you and others.
• You trust a friend's word based on their past honesty.

You don't have mathematical proof they will never fail you, but your trust is not blind. It's a response to what you have good reason to see as trustworthy.

5.2 Faith and knowledge

On this view, faith and knowledge are not opposites:

• Knowledge, in a broad sense, is having good reasons for thinking a belief is true.
• Faith is a commitment or reliance based on what you take to be those good reasons.

Everyone, including skeptics, places "faith" in some things: in the reliability of reason, in the uniformity of nature, in other minds existing, in some moral principles being real. The question is less "Do you have faith?" and more "What do you trust, and why?"

6. Are miracles ever believable?

6.1 What is a miracle?

A simple working definition:

A miracle is an event that goes beyond what we would expect from the usual patterns of nature, in a way that seems connected to a purpose or meaning.

It might involve:

• Timing (something happens at just the right moment).
• A departure from normal physical patterns (like an unexpectedly rapid healing).
• A convergence of events that seems hard to explain by chance alone.

Different worldviews interpret these things differently: some see them as impossible in principle, others as possible but rare, others as expected in certain contexts.

6.2 How would we assess miracle claims?

We can approach miracle claims using the same tools we've been talking about:

• Evidence: What actually happened? What are the sources? Are there independent witnesses? Are there alternative explanations (misdiagnosis, fraud, coincidence)?
• Background beliefs: Do we already assume that any non‑natural explanation is impossible? If so, no amount of evidence will move us.
• Comparing explanations: Which explanation fits best with all the data—natural, psychological, social, and (potentially) non‑natural?

The key point is that miracle claims can be evaluated, rather than being automatically believed or automatically dismissed. Whether any given claim stands up is a separate question, but the tools are the same: evidence, reasoning, and honesty about our starting assumptions.

Where this leaves us

In this guide, we've tried to sketch how knowing works at a high level:

• We use different kinds of evidence—scientific, historical, logical, experiential—for different kinds of questions.
• Absolute certainty is rare, but responsible belief is still possible; we live with degrees of confidence.
• Reason, emotion, and intuition all play roles, with reason and evidence checking our impulses.
• Our senses and minds are fallible but generally reliable, and we can correct course over time.
• "Faith," broadly understood, is not believing in spite of evidence, but placing trust based on what we take to be good reasons.
• Even miracle claims can, in principle, be examined with the same tools.

All of this matters because big questions about reality, morality, and any religious or secular worldview are knowledge questions. They are not settled by feelings alone, nor by lab tests alone. They call for the whole toolkit.

From here, we can start asking:

• What does the available evidence—scientific, historical, philosophical—seem to point to?
• Which big-picture stories about reality make the most sense of that evidence?
• How should we respond if a worldview seems to fit reality better than the alternatives?

Those are the questions that the rest of this project will keep returning to.