The Most Important Thing You Can Understand About Quantum Physics

This piece will teach you the single most crucial insight into quantum physics — truly, it’s the most important takeaway. But first, let’s discuss Lego bricks.

Lego, really?

When you build with Lego, it’s obvious how things fit together: bricks snap, towers need wide bases, and angled structures provide stability.

But have you ever wondered where these rules come from?

Are they built into the material itself? If you melted down Lego bricks into a puddle of plastic, would you find instructions floating inside the liquid, telling it how to snap together?

No. The chemistry of plastic sets the stage — strength, flexibility, and so on — but it doesn’t dictate how you should arrange bricks to form a castle or spaceship.

The concept of “snapping together” doesn’t exist at the level of polymer molecules. At that microscopic scale, it’s all about molecular bonds and electron clouds. We can, in principle, say that these fundamental molecular rules allow the plastic to form Lego bricks that “snap,” but you can’t look at a single polymer chain and see any sign of that snapping behavior.

Where reductionism falls short

We often hear that if you know the fundamental rules deeply enough, you can derive everything else.

Technically, that’s true.

The molecular structure of plastic implies the possibility of Lego bricks. But practically, trying to start from molecular physics and end up with “how to build a stable Lego tower” is hopelessly complex.

It’s not that the fundamental rules are wrong or incomplete. It’s simply that emergent phenomena — like snapping bricks together — live at a different level of explanation.

Moreover, once you’re talking about emergent rules (like Lego design principles), those rules don’t help you understand fundamental chemistry. Learning about “snap-fitting” can’t tell you why polymers bend a certain way or how petroleum is refined. There’s a “screening off” effect in both directions.

The screening goes from lower to higher levels. While molecular physics enables Lego…