You can tell a lot about a person by what lights up their eyes in conversation. Some folks reach for the weather or the latest petty outrage; others lean into ideas that stretch time, cross disciplines, and admit complexity.

I won’t pretend to have it all figured out, but after six-plus decades of kitchen-table debates, office break rooms, and long walks with my grandkids (and my dog Lottie tugging the lead), I’ve noticed that high-level thinkers tend to love talking about the same kinds of things—and not because it makes them sound smart, but because it helps them live better.

Below are the topics that, in my experience, separate surface talkers from deep thinkers.

If you, or someone you know, genuinely enjoys these, you’re likely dealing with a mind that can hold nuance, change its mind, and build something useful from conversation.

1. First principles, not just positions

High-level thinkers want to know what something is made of. Instead of memorizing a stance, they pull it apart: What’s the core assumption? What happens if we question it? They’re the ones in a policy chat asking, “What problem are we actually trying to solve?” It’s not combative; it’s clarifying. The goal isn’t to win a point—it’s to stand on bedrock before you start building.

2. Trade-offs and opportunity cost

They know every “yes” hides a dozen “no’s.” So they like conversations that name the price of choices—time, attention, money, reputation—and ask whether the trade is worth it. When someone says, “We should add one more feature,” they counter with, “At the cost of which bug fix?” It’s the grown-up way of thinking: you can have anything, not everything.

3. Second-order effects and unintended consequences

High-level thinkers resist “and then a miracle occurs.” They like to run the tape forward. If we cap rent, who maintains buildings five years out? If we widen the road, how long until traffic grows to fill it again? It’s not cynicism; it’s respect for cause and effect.

Years ago, our neighborhood petitioned to close a little cut-through street to slow traffic near the park. The idea was simple and popular—until a few of us (picture a ragtag committee with clipboards) traced the ripple effects. Emergency vehicles would lose their fastest route.

The closure would push drivers onto a narrower road lined with kids’ bikes. And the coffee shop that relied on morning drive-bys would take a hit. We stood in the drizzle with a city planner and sketched alternatives: raised crosswalks, a chicane, better lighting, a flashing sign keyed to real speed.

We didn’t kill the idea; we improved it by thinking past step one.

The final plan took longer and wasn’t as flashy, but it made the park safer and kept the neighborhood humming. That’s second-order thinking in the wild.

4. Systems and feedback loops

Give them any mess—sleep habits, supply chains, family calendars—and they’ll look for loops. Where are we reinforcing the problem?

Where could a tiny tweak shift the whole system? They love questions like, “What small change upstream would make the downstream calmer?” It’s elegant thinking because it saves willpower by redesigning the machine.

5. Ethics in gray zones

They don’t only want to know what’s legal; they want to know what’s right when life serves up edge cases. How much transparency does a leader owe when privacy is at stake? When does “helping” become control?

The conversation isn’t a purity test; it’s an exercise in moral attention. These are the folks who can hold two decent values in tension without scorching either.

6. History as pattern, not trivia

High-level thinkers don’t quote history to sound erudite; they mine it for rhyme. They’ll say, “This feels a lot like railroads in the 19th century—booms, busts, consolidation,” not to show off, but to borrow old lessons. History becomes a workshop manual, not a museum tour.

7. Learning how to learn

They’re fascinated by the process of getting smarter—spaced repetition, interleaving, deliberate practice, teaching as a way to encode memory.

If you’re a regular reader here, you may remember I once wrote about building a “second brain” with notebooks and bite-sized review sessions; high-level thinkers eat that stuff up because it compounds.

They talk techniques the way athletes talk drills.

8. Failure, iteration, and post-mortems

They don’t treat mistakes as moral indictments; they treat them as data. What did we learn? What will we try next Tuesday?

Their favorite question after a flop is, “What would make it hard to fail the same way again?” It’s why conversations with them feel hopeful even when the news isn’t.

9. Probabilistic thinking and uncertainty

Instead of pretending they’re certain, they give odds. “I’m 70% confident this will work, but if we see X by Friday, I’ll update.” That kind of talk is catnip to high-level thinkers because it leaves room to get smarter without losing face.

It also reduces arguments; you can disagree about percentages without turning each other into villains.

10. Psychological safety and the conditions for truth

They care less about being right and more about creating rooms where truth can get said.

They like to discuss how teams actually work: How do we surface dissent early? How do we make it cheap to bring a half-formed idea? What’s the ritual for changing our minds without humiliation?

It’s not soft stuff. It’s the scaffolding for real results.

On a volunteer committee I joined after retiring, a brilliant young analyst kept going quiet during meetings. Her work sang on paper; in the room, she withdrew.

One afternoon I asked her to walk Lottie with me and talk through what shut her down. “Every idea arrives to a firing squad,” she said. She wasn’t wrong—our chair prided himself on “stress-testing” ideas, which mostly meant interrupting. At the next meeting I floated a new rule: first, one minute to understand; only then, questions.

It felt almost silly—one minute!—but the energy shifted. The analyst spoke earlier and more often. We caught a flaw in a budget proposal we would’ve missed. The chair—an old friend—pulled me aside later and said, half-joking, “You turned the guns into spotlights.”

The real point: high-level thinkers like talking about conditions because the right conditions change everything.

11. Language, framing, and the power of definitions

They know a single word can tilt a decision. Is it a “tax” or a “membership fee”? Are we “cutting” or “right-sizing”? Conversations with them often begin with, “Before we debate, what do we mean by…?” It sounds pedantic until you realize half of fights vanish when terms get clear.

12. Energy, not just time

They don’t ask only, “Do I have an hour?” They ask, “Do I have the attention for this hour?” They like to compare notes on sleep, light, movement, and breaks—not to gamify life, but to aim their best mental hours at their hardest problems. It’s the difference between being busy and being useful.

13. Compounding and long games

They love the quiet math of doing a small thing repeatedly: friendships watered on schedule, savings added automatically, skill drills done daily. It’s less about obsession and more about respect for curves that start flat and suddenly climb. They talk long horizons because they’ve seen the payoff.

14. Cross-disciplinary mash-ups

A high-level thinker will borrow a concept from gardening to solve a management problem, or apply jazz improvisation principles to brainstorming.

They enjoy conversations that yoke unlike things together and see what sparks. They’re allergic to silos; they want the kitchen drawer where all the useful tools live.

15. Designing environments and defaults

They’d rather move the trash can than make a new vow. They like to ask, “How can we make the right action the easy one?”

That might mean putting the guitar on a stand in the living room, setting Do Not Disturb for two hours each morning, or keeping fruit at eye level. It’s merciful thinking: change the setting, save the willpower.

A few ways to have these conversations without being “that person”

• Lead with questions, not lectures. “How would we test the opposite?” gets more traction than a five-minute monologue.

• Offer one model, not a library. Share the concept that helped you last week; save the TED Talk for later.

• Admit what would change your mind. Put your exit ramps on the table. It invites other people to do the same.

• Anchor ideas in ordinary life. Talk compounding via friendships, not just finance. Talk systems via your morning routine, not just supply chains.

Why these topics matter (beyond sounding clever)

They don’t just make for stimulating talk. They’re practical. First principles save you from solving the wrong problem. Trade-offs keep calendars sane. Second-order thinking prevents avoidable messes. Systems and safety turn groups into teams.

Probabilistic thinking reduces stubbornness. Language keeps fights honest. Compounding builds lives that feel stable instead of frantic. In other words, these topics are the upstream of better days.

If you’re reading this and thinking, I’d like more of these conversations in my life, start small. Pick one topic from the list and weave it into a chat this week. Ask your partner, “What’s the first-principles version of this?”

Ask a friend, “What second-order effects are we missing?” Try a one-minute-understanding rule in your next meeting. Watch what changes.

And if you already love talking like this, keep going.

Find the people who don’t roll their eyes when you ask for definitions or percentages.

Invite them on a walk.

Bring a thermos.

Toss one good question into the air and follow wherever it leads. With the right company, you’ll come home with a clearer head, a calmer plan, and the pleasant ache of having used your mind well—still the best feeling I know at my age.