Know: 10 Essential, Simple Ways to Verify Information Online

Know: a practical guide to understanding, verifying and using knowledge

Every day we decide what to buy, who to trust, and how to act. At the heart of each decision is a simple question: how do we know? We use the word all the time—“I know this is true”, “I don’t know”, “I’ll let you know”—but few of us stop to ask what it really means to know, how we come to know things, and how we can know better. This guide offers a clear, friendly tour of the concept, showing practical ways to strengthen your understanding, avoid common traps, and make more confident choices.

Whether you want to know if a claim is reliable, know how to learn a new skill, or know when to change your mind, you’ll find tools you can use straight away. We’ll also highlight useful resources and examples so you can practise and build the habits that make good judgement easier over time.

What does it mean to know?

In everyday English, to know is to be certain or highly confident about something. You might know your address, know how to ride a bicycle, or know a person well. Philosophers often define knowledge as “justified true belief”: you believe it, it is true, and you have good reasons or evidence. The details can get complex, but for practical purposes, it helps to think of knowledge as accurate, well-supported understanding you can act on.

Crucially, to know is different from guessing or assuming. You can believe something by accident and still be wrong. You can also be right by luck, without really knowing why. In daily life, we aim to move from mere opinion towards things we genuinely know by checking evidence, seeking reliable sources, and being willing to revise our views when better information appears.

Types of knowing

Knowing-that (facts and explanations)

This is factual knowledge: you know that Paris is the capital of France, or that water boils at 100°C at sea level. It includes concepts, explanations, and the ability to state reasons. School learning often focuses here, but adults use it constantly—comparing phone plans, understanding mortgage terms, or following a news story.

Knowing-how (skills and techniques)

This is practical ability: you know how to cook a risotto, change a tyre, or use a spreadsheet. You can demonstrate it. Often, you start with knowing-that (instructions) and only really know when you practise enough to do it reliably and adapt to new situations.

Knowing-by-acquaintance (familiarity and experience)

This is personal familiarity: you know your favourite café’s atmosphere, or recognise a friend’s voice. It’s built through direct experience and can be hard to put into words. Still, it guides countless everyday judgments.

How we come to know

Most of what we know comes from a handful of sources, used together.

• Perception: seeing, hearing, touching and more. We observe patterns, spot changes, and notice details.
• Testimony: what other people tell us, in person or through writing, media, and expert advice.
• Memory: what we recall from past experiences or learning.
• Reasoning: connecting ideas, spotting contradictions, and drawing conclusions from evidence.

We rarely rely on just one source. If you want to know whether a product is worth buying, you might read reviews (testimony), check specifications (facts), compare prices (reasoning), and ask a friend who has tried it (testimony + acquaintance). By combining sources and seeking consistency between them, you improve your chances of arriving at things you truly know.

How to know if a claim is reliable: a step-by-step guide

Here is a practical method you can use to decide whether to believe, doubt, or research further. Use it flexibly; the point is to help you know with greater confidence.

Step 1: Define the question clearly

Pin down exactly what you want to know. “Does this diet work?” is vague. “Does this diet lead to significant weight loss in adults after 12 weeks compared with a balanced calorie deficit?” is specific and helps you look for the right kind of evidence.

Step 2: Find diverse, credible sources

• Prefer primary sources (original studies, official statistics) when feasible.
• Use reputable secondary sources that summarise evidence accurately.
• Compare viewpoints; do not stop at the first result that tells you what you want to hear.

In the UK, an excellent place to start for media literacy is Ofcom’s research pages, which offer insight into how people encounter and assess information online; see Ofcom’s media literacy research. For analytical context on the concept of knowledge, the Stanford Encyclopedia of Philosophy’s overview of knowledge provides a thorough, accessible explanation.

Step 3: Evaluate the evidence

• Check sources: Who produced this? Are they qualified? Do they have a financial or ideological interest?
• Check methods: How was the data gathered? Is the sample size adequate? Are results reproducible?
• Check claims: Are conclusions stronger than the evidence justifies? Are uncertainties acknowledged?
• Check context: Is this typical or an outlier? Are there contradictory findings you should consider?

Professional fact-checkers model these habits daily. In the UK, Full Fact’s explainers and checks show how to examine claims about statistics, policies, and public debates. Observing their methods can improve the way you know and the confidence you place in your conclusions.

Step 4: Synthesis and confidence, not certainty

Put the pieces together and choose a provisional conclusion. The aim is not to be certain about everything, but to know enough to act sensibly—while remaining open to revision if strong new evidence appears. Good judgement means you know what you know, know what you don’t, and know the difference.

Common mistakes when we think we know

Even well-intentioned people can be misled. Becoming aware of common errors helps you know better.

Confirmation bias

We tend to notice and believe information that supports what we already think, and ignore or discount what challenges it. To counter this, deliberately seek out high-quality sources that argue the opposite of your initial view. This makes what you ultimately know more robust.

Dunning–Kruger effect

When we’re new to a topic, we may overestimate how much we know. As we learn, we discover complexities and become more realistic. A simple habit is to ask, “What would change my mind?” If you can’t answer, you may not yet know enough to be confident.

Confusing correlation with causation

Two things happening together does not mean one caused the other. Ice cream sales and sunburn both rise in summer; one does not cause the other. To know whether A causes B, look for experiments, temporal order (cause before effect), plausible mechanisms, and the ruling out of alternatives.

Overreliance on personal experience

Experience matters, but it is limited and can be unrepresentative. You might know your own results with a diet, but broad claims require representative evidence. Balancing personal knowledge with wider data helps you know where your experience fits within the bigger picture.

Using language to show what you know

Clear language helps you communicate what you know—and what you don’t—without overstating. Phrases like “the evidence suggests”, “this is likely”, or “we don’t yet know” signal honest confidence levels. Choosing precise words also matters. For instance, some contexts call for “numerous”, others for “many”, “countless”, or “abundant”. If you’re exploring vocabulary, this concise guide to synonyms for numerous can help you refine how you describe what you know.

Being careful with definitions avoids confusion. When a discussion hinges on what a term means—whether “organic”, “sustainable”, or a historical label—it helps to pause and agree on the definition before debating. That way, everyone can know they are speaking about the same thing.

Everyday examples: ways to know better in daily decisions

Health choices

Suppose you want to know if a supplement is worth taking. Start with reputable sources such as NHS advice or systematic reviews in medical journals. Look for consensus and note uncertainties. If claims are extraordinary—“cures dozens of conditions”—you should expect extraordinary evidence. When evidence is mixed, the honest answer may be: we don’t yet know enough.

Money matters

When comparing savings accounts, you want to know the real returns after fees and tax. Read the small print, compare like with like, and use independent calculators. When risk is involved (e.g., investments), ensure you know your risk tolerance and time horizon before deciding.

News and public life

Public claims can be complex and emotionally charged. To know whether a viral story is accurate, check dates, sources, and context. Seek corroboration from outlets with strong editorial standards. If a headline seems designed to provoke, read the full article and original sources before sharing; that alone will help you know far more than most click-driven reactions.

History and culture

Questions about tradition or belief often circulate online. If you want to know whether a cultural practice has ancient roots or modern origins, follow citations to primary sources and scholarly summaries. As a case study in examining a popular claim, consider this balanced discussion on is Easter pagan? which shows how definitions and sources affect what we think we know.

A practical checklist to strengthen what you know

• Clarify your question: what exactly do you want to know?
• Look beyond one source: triangulate between credible viewpoints.
• Check the author: who are they, and what do they stand to gain?
• Inspect the evidence: methods, data quality, and limitations.
• Beware of certainty theatre: strong claims need strong support.
• Note your confidence level: high, medium, or low—and why.
• Be ready to update: when evidence changes, what you know should change too.

Building durable knowledge: habits that last

To genuinely know in the long term, treat learning as a cycle: encounter, test, reflect, and apply. Spaced repetition helps facts stick; deliberate practice improves skills; discussion with people who disagree tests your reasoning. Over time, you will not only know more—you will know how to know efficiently.

Try keeping a “knowledge log”. When you make a decision, note what you believed, why you believed it, and what would change your mind. Later, review the outcome. This habit tightens the link between what you think you know and what actually works.

Examples of “calibrated” language that shows what you know

• High confidence: “Multiple high-quality studies indicate… I know from the evidence that…”
• Moderate confidence: “The balance of evidence suggests… I think we can reasonably know that…”
• Low confidence: “Preliminary findings hint… We don’t yet know; more data are needed.”

Calibration encourages intellectual honesty. It shows you know the limits of your information, which paradoxically makes others more likely to trust what you say you know.

From knowing-that to knowing-how

Many goals require both. If you want to know how to speak a new language, you’ll need vocabulary and grammar (knowing-that) and repeated, real use (knowing-how). Plan your learning so you alternate theory with practice: read, then speak; study, then do. You will make mistakes; that is how you come to know what works.

What if two experts disagree—how can you know who to trust?

Disagreement is normal in complex fields. To judge, consider:

• Evidence quality: who relies on stronger, more transparent data?
• Track record: whose past predictions or analyses have held up?
• Peer standing: do other qualified experts take them seriously?
• Disclosure: who is open about conflicts of interest and uncertainty?

When true uncertainty remains, the responsible answer may be that we cannot yet know. Making decisions under uncertainty is common; acknowledge it, and choose proportionate actions while remaining ready to update what you know.

Recommended external resources

• Introductory overview of knowledge (Wikipedia)
• In-depth analysis of knowledge (Stanford Encyclopedia of Philosophy)
• Media literacy research and guidance (Ofcom)
• Independent fact-checking and guides to claims (Full Fact)

Frequently asked questions about know

What is the difference between believe and know?

Belief is accepting something as true; knowledge requires good reasons and accuracy. You can believe by guesswork, but to know you need evidence or justification. In practice, you can treat knowledge as belief plus reliable support and the willingness to update when strong evidence appears.

Can I ever be 100% certain that I know something?

In everyday life, certainty is rare and often unnecessary. Aim for appropriate confidence. You may be virtually certain about your name or your birthday; most other topics benefit from “high confidence” rather than absolute certainty. You still know enough to act sensibly.

How can I know if a source is credible?

Check who wrote it, their qualifications, whether they cite evidence, and if reputable outlets endorse or criticise it. Look for transparency about methods and conflicts of interest. Cross-check with independent sources. If it sounds too good to be true, probe further before deciding you know.

What should I do when experts disagree?

Compare evidence quality, look for areas of consensus, and note how each expert handles uncertainty. If the matter is urgent, act proportionately to the risks while acknowledging what you don’t yet know. Keep monitoring as new evidence arrives.

How do I move from “knowing-that” to “knowing-how”?

Alternate study and practice. Start with reliable instructions, then practise in small steps with feedback. Reflect on mistakes and adjust. Over time, you will not just know facts about the skill—you will know how to do it under varied conditions.

Is it a problem to change what I know?

No. Updating is a strength, not a weakness. It shows you care about truth and effectiveness. As better evidence appears, revising what you know improves your decisions and results.

Conclusion on know

To know is more than to believe—it is to understand with good reasons, to judge evidence fairly, and to act with appropriate confidence. In daily life, you build what you know by combining perception, testimony, memory, and reasoning, then testing your conclusions against reliable sources and real outcomes.

Practical habits help: define your question, seek diverse credible sources, evaluate methods and motivations, and state your confidence honestly. When you make a mistake, learn from it; when evidence changes, update what you know. Clear language and careful calibration make it easier for others to see the strength of what you claim to know.

If you adopt these simple routines, you will not only know more—you will know better. And that kind of knowing steadily improves your choices, your conversations, and your confidence in a noisy world.