Critical thinking in practice

Critical thinking isn’t a personality type. It’s also more than a mindset. First and foremost, it’s a disciplined set of habits. To paraphrase James Clear, the author of Atomic Habits, we do not rise to the level of our goals; we fall to the level of our habits. So, it’s not enough to believe in critical thinking; we have to train it like a muscle – it strengthens through disciplined reps. Over time, these routines become second nature, giving our thinking the resilience to hold up under the pressure and pace of daily life.

My last post outlined the critical-thinking mindset in an age of AI. This one outlines nine habits to help embed that frame of mind into your daily routines.

1. Read, listen and watch widely

Critical thinking is not a free-floating technique; it’s a proactive engagement with facts, information and opinions. Critical thinkers don’t just passively consume their ‘filter bubble’ feed — they select a range of perspectives that stretch and refine their understanding. A broad information diet helps them spot patterns, contextualise evidence, and know exactly where to probe and what to ask.

They actively seek out clever people and opinions, including those they disagree with. Comfortable with their assumptions being tested, not coddled, they are open to sharpening their opinion in the face of new information or a more compelling argument. They see changing their mind as growth and progress, rather than a sign of weakness.

Discomfort is data — pay attention to it.

2. Adapt to the specific context

Sound decisions start with seeing the situation clearly and framing the context around the subject at hand, which determines what kind of thinking the moment needs. Critical thinking isn’t a fixed routine; it flexes to the circumstances. Good thinkers read the room, the stakes and the constraints. They know that every decision sits in a web of agendas, incentives, timelines and imperfect data.

Product teams make hundreds of calls a day. Most don’t need forensic analysis. The real skill is recognising which decisions deserve slow thinking. In his book, Build, Tony Fadell draws a helpful distinction between two types of decision: data-driven decisions, which can be tested with evidence, and opinion-driven decisions, which rely on debate and judgment when data is scarce. Both need critical thinking — but not the same kind. One leans on analytical rigour; the other on challenge and counter-argument.

Critical thinkers match their approach to the moment.

3. Surface your assumptions

Assumptions are the hidden scaffolding of our thinking — the beliefs we treat as obvious that don’t need checking. Making them explicit gives us and our colleagues something to test, challenge and improve.

Every domain has its favourite fictions — here are a few classics from the past:

• ‘If we build it, they will come’
• ‘Touch screens will never be good enough to type quickly on’
• ‘We own the customer, so they’ll use our app store’
• ‘Our brand perception won’t be a barrier to moving upmarket’
• ‘Customer service chatbots won’t impact brand loyalty’
• ‘Younger users don’t care about privacy’

When assumptions lie hidden, they become silent drivers of flawed thinking. We slip into false certainty and mistake belief for fact. Groupthink thrives as premises go undiscussed. And when plans rest on wishful thinking, organisations become strategically blind.

The antidote is simple: surface the assumptions. Log them. Run pre-mortems. Ask ‘What must be true for this to work?’. Expose your assumptions before they expose you.

4. Write it out

Writing, like sketching, is a great way of getting thoughts out of your head and into the world, where they can be more clearly assessed. Just like we clarify design concepts through sketching and re-sketching, we refine more abstract concepts through writing and re-writing. The act of putting words down forces meaning to surface. Writing is thinking in slow motion — it exposes gaps, sharpens intent and turns intuition into reasoning.

Strong thinkers have always known this:

• ‘If you’re thinking without writing, you only think you’re thinking’, Leslie Lamport
• ‘I write entirely to find out what I’m thinking. What I’m looking at, what I see and what it means.’, Joan Didion
• ‘Ideas that are flaky appear even more so when committed to paper. Conversely, ideas that are inherently strong get even stronger through the discipline of writing, ’ Gary Hamel
• ‘I write because I realised at art school that you can only draw a small percentage of the attributes of an object. If I were to draw a glass, you would understand only 20 per cent of its nature. You would have no sense of its weight, or material, or temperature. You would have no sense of how it reacted to its environment. Writing helps me frame the problem. A lot of mistakes are made when you frame a problem, because you could already be dismissing 60 per cent of the potential ideas.’, Jony Ive

The same logic applies to GenAI. Prompting is writing: the clarity of your input shapes the quality of the output. Loaded questions, hidden assumptions and sloppy framing produce biased or vague responses. And editing GenAI text is non-negotiable. AI has no understanding, judgment or intent — which means you are accountable for the meaning, accuracy and tone of anything you ship.

AI accelerates drafting; writing preserves judgment.

5. Embrace nuance

In polarised and distracted times, the path of least resistance is to let our thinking be framed by headlines and social media hot takes. These perspectives tend towards black-and-white thinking that flattens complex issues into neat binaries. Good vs bad, success vs failure, quality vs speed — these oppositions make conversations easier but decisions worse.

Critical thinkers distrust such Manichean simplicity. The truth and wise choices usually lie in grey areas of trade-offs between competing priorities and coexisting perspectives. Rarely is it a question of either-or; it’s almost always a subtle combination of both.

Teenagers argue in black and white; grown-ups work in gradients.

6. Make discerning distinctions

Working in gradients does not imply blurring the lines between them. Drawing useful contrasts lies at the heart of clear thinking. It sharpens understanding by separating things that look similar but work differently. Useful is the operative word — because distinctions that don’t clarify can quickly slip into pedantry. Making distinctions isn’t about splitting hairs; it’s about revealing structure and adding precision. When we make discerning distinctions, we see relationships more clearly and create the conditions for better conversations, sounder judgments, and richer alignment.

Critical thinkers clarify confusion and reveal insight, for example, by distinguishing between needs and wants, between simplicity and usability, and between customisation and personalisation.

The right lines don’t divide thinking — they focus it.

7. Steelman counter-arguments

When faced with opposing views, engage with their strongest version. This is the opposite of the strawman tactic, where we attack a flimsy caricature of someone’s argument — the kind they’d never actually make.

Steel-manning takes generosity and discipline. Restate the opposing case as clearly and persuasively as possible — sometimes better than its originator. Then test and refine your position against it.

This approach doesn’t just sharpen reasoning; it builds credibility and trust. People are far more likely to listen when they feel heard and accurately represented. And if your argument still holds after you’ve strengthened the opposing one, it will stand on firmer ground.

Sharpen your sword on the hardest stone.

8. Make time for quality checks

One impact of GenAI is that it shifts where we focus our attention. Used wisely, it can streamline research, idea generation and visualisation, among other tasks. But working with AI creates work elsewhere. Managers are still accountable for their team’s output, yet quality-checking GenAI requires a different approach.

When chatbots can nail tone, structure and grammar, surface polish stops being a reliable quality signal, but AI doesn’t ‘know’ things; it predicts plausible text, pixels and code.

Here are three quality checks to run on GenAI content:

1. Traps, not typos: AI can appear convincing but be wrong, precise but invented, confident but unfounded. Scrutinise any fact, stat or claim you’d be embarrassed to defend in a meeting.

2. Logic, not just the conclusion: AI often sounds persuasive at first blush, but on a slower second reading, it can lose the plot. Break the answer into steps and check whether each one actually supports the next. If you can’t restate the argument clearly in your own words, you don’t really have one – even if you like the conclusion.

3. Alignment, not just correctness: AI feigns awareness of your context, culture and content, but it actually understands none of it. It often subtly changes the question or blurs your intent. Check for hidden drift: does this response still answer your question, for your vision and setting?

Domain knowledge really matters here. The more you understand the space, the easier it is to smell when something is off – no matter how slick the output looks.

GenAI shifts the effort from creation to verification. Critical thinkers own the sign-off.

9. Think for yourself, but not by yourself

Good thinking starts alone — noticing your own biases, checking your assumptions, spotting where you might be fooling yourself. But it gets much sharper through conversation. Critical thinkers invite good-faith challenges to their reasoning, evidence and interpretations. They don’t fear pushback; they rely on it.

Ed Catmull, co-founder of Pixar, advises managers to ‘put smart, passionate people in a room together, charge them with identifying and solving problems, and encourage them to be candid with one another.’ Teams that normalise respectful, constructive challenges raise the collective quality of their work — and surface blind spots no one could see alone.

The real power of these habits lies in how they spread. When teams share a language, reward good questions, and normalise reflection, critical thinking becomes a collective reflex — not a personal virtue.

You can’t control the noise, the pace or the algorithms — but you can control your habits. And the right habits keep judgment grounded and sharp. Clarity isn’t a gift – it’s a practice.

PS. This article began life as a ‘lunch and learn’ talk I gave to a client team. Let me know if you’d like me to present it to your team (or class). Sample slides here.