Is It Still the Same Thing?
Long ago, the people of Athens kept the ship of their greatest hero, Theseus. Whenever a wooden plank rotted, they replaced it with a new one. After many years, every single plank had been replaced. So... was it still the Ship of Theseus? People have argued about this puzzle for 2,000 years, and it's about more than ships. It's about YOU.
This is our third philosophy thought experiment! Plato asked "What is real?" Schrödinger asked "Is it decided before we look?" Now we ask: What makes something the SAME thing over time?
Your path
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The Story
A puzzle from ancient Greece, in four parts.
Words to Know
Tap each card to flip it.
Check your understanding
Ship Lab
You're the shipbuilder. Replace the planks yourself!
Step 1: Replace the planks
The ship has 20 old planks. Click a plank to replace it with a new one (or use the button). After each one, decide: is it still the Ship of Theseus?
Right now, is this still the Ship of Theseus?
Step 2: The Twist! 🔄
About 400 years ago, an English philosopher named Thomas Hobbes added a sneaky twist. What if someone secretly saved every old plank you removed... and used them to build a second ship?
Which one is the REAL Ship of Theseus?
Fix the Ship!
Keep the ship afloat for 45 seconds.
Planks are rotting! A rotting plank turns dark red and drips. Click it fast to replace it with a new plank. If 4 planks rot at the same time, the ship sinks! Watch out: even new planks get old and rot eventually.
The Human Ship
Your body replaces its parts too. So who is the real you?
Myth or fact?
You may have heard: "Every 7 years, every cell in your body is replaced, so you're a completely new person!"
Explore your body's "planks"
Your body is made of trillions of tiny living pieces called cells. Different kinds of cells get replaced at very different speeds. Tap each dot to find out how fast. Explore all 9!
Tap a dot
Each dot is a different part of your body. 0 of 9 explored
So... who's the real you?
If lots of your cells are replaced over your life, what makes you still you? Choose everything you think is part of the "real you."
Classroom Object Activity
Replace parts of a classroom object and debate when it becomes "different."
Step 1: Pick an object
Step 2: Replace the parts
Replace one part at a time. After each replacement, vote: is it the same object, or a different one?
Right now, is it still the SAME object?
Step 3: Try it for real in class!
Opinion meters: same or different?
There's no wrong answer here. Slide each one to show what YOU think.
Big Questions
Let's think about it.
Philosophy isn't about finding the one "right" answer. It's about thinking carefully and being able to explain why you think what you think.
Writing Task: Type your response to each question. Write at least 2 sentences for each. You may be asked to share your responses. We will discuss this as a class.
Class Debate
What makes something the same thing?
Philosophers have given different answers. Pick the one that sounds most right to you. Be ready to defend it in our class discussion!
Evidence and examples that support your side:
Reflection
Wrapping Up: Final Response
Write a thoughtful response that answers the questions below. Do not simply answer each question separately. Connect your ideas into one strong piece of writing.
Your response should:
Push Your Thinking
My final response
Writing Expectations
Turn it in with Google Docs
This puts everything you wrote and decided in this unit into a Google Doc.