Does the Grandfather Paradox Exist in Doraemon? How the Author Addresses Logical Issues in Time Travel

Hello! It's great to chat with you about this topic. Doraemon's time travel is indeed a fascinating concept, and many fans have pondered its implications.

Simply put, the "grandfather paradox" does appear in Doraemon, but author Fujiko F. Fujio cleverly resolves it using a set of ingenious and "gentle" rules. This allows the story to maintain internal consistency while remaining full of imagination.

Let me break down how the author handles these logical issues.

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First, What is the "Grandfather Paradox"?

Let's explain this concept in plain language.

Suppose you travel back in time and eliminate your grandfather before your father is born. Then the problem arises:

1. Without your grandfather, your father wouldn't exist.
2. Without your father, you wouldn't exist.
3. If you never existed, then who traveled back in time to eliminate your grandfather?

You see, this creates a dead-end loop, a logical knot that can't be untied. This is the "grandfather paradox."

The "Sewashi Paradox" in Doraemon

In Doraemon, the most classic example resembling the "grandfather paradox" is the appearance of Nobita's great-great-grandson, Sewashi.

• Original Timeline: Nobita grows up and marries Gian's sister, Jaiko. He starts a company that goes bankrupt, leaving his descendants living in poverty. Sewashi is born into this "miserable future."
• Sewashi's Action: To change this future, he sends Doraemon back in time to help Nobita.
• Altered Timeline: With Nobita's efforts and Doraemon's help, Nobita eventually marries his childhood crush, Shizuka.
• The Paradox Arises: Since Nobita marries Shizuka, his entire bloodline changes. Sewashi, the great-great-grandson descended from "Nobita + Jaiko," logically should never be born. But if Sewashi doesn't exist, who sent Doraemon back?

You see, isn't this a version of the "grandfather paradox"?

The Author's Solution: Three Core Principles

Fujiko-sensei didn't let the story get stuck here. Instead, through various details in the manga, he established a unique set of "Doraemon Time-Space Rules."

Principle 1: History's "Self-Correcting Force" (or "Historical Inertia")

Think of history as a great river with a fixed course it must follow (e.g., a certain person is destined to become a scientist).

Traveling back in time is like throwing a small stone into the river. It might create some ripples (changing minor events), but the water quickly smooths them out and continues flowing in its original direction.

• Example: In short stories, no matter how hard Nobita tries to use Doraemon's gadgets to score 100 on a test, he always fails for some bizarre reason (like writing his name wrong or being accused of cheating), ultimately scoring zero. This demonstrates the powerful self-correcting force of the "historical inevitability" that "Nobita scores zero."

This principle handles "harmless" changes. You can alter the process, but not the ultimate "major outcome."

Principle 2: The "Parallel Worlds" Theory (The Official Final Explanation)

This is the most crucial principle for resolving the "Sewashi Paradox"!

In the manga, Sewashi himself explains this issue. His words essentially mean:

"Even though Grandma changed from Jaiko to Shizuka, and the process was altered, it's like going to Osaka. You can take the Shinkansen, fly, or even walk. The route is different, but you still reach Osaka, the destination. My birth is that 'destination.'"

This explanation is essentially a simplified version of the "parallel worlds" theory.

• It can be understood this way: When Doraemon intervenes in Nobita's past, history splits at that point, creating a new branch and forming a new parallel world.
• The original worldline (Nobita marries Jaiko) does not disappear. It still exists. Sewashi comes from that worldline.
• The Nobita we follow in the story is heading towards a new worldline (Nobita marries Shizuka).
• Although the great-grandmothers are different in the two lines, they both ultimately lead to the result of "Sewashi being born." This is a bit metaphysical, but it's the author's official "patch," meaning that no matter who Nobita marries, among his descendants, there will always be a child named "Sewashi."

This setup is brilliant. It acknowledges that "changing the past" is effective while avoiding the paradox of "erasing the existence of the changer."

Principle 3: The Enforcing Power of the "Time Patrol"

To prevent people from using time travel for extreme actions (like giving ancient people an atomic bomb and completely overturning history), the author also created an official organization – the Time Patrol.

Their existence acts as an "insurance policy" for time travel.

• They usually ignore trivial matters, like helping Nobita with homework or setting him up with Shizuka. These fall within the range tolerated by "history's self-correcting force."
• But if someone attempts a "major historical crime," like changing the outcome of a war or causing a species to go extinct prematurely, they will intervene, arrest the person, and repair the damaged history.

This is like the GM (Game Master) in a game, ensuring players (time travelers) don't crash the entire server (history).

To Summarize

So, back to your question: Does the grandfather paradox exist in Doraemon?

The answer is: Theoretically, yes, but the author perfectly circumvented it using a very self-consistent set of rules.

• For minor, inconsequential changes, "history's self-correcting force" explains them, as they don't affect the big picture anyway.
• For changes significant enough to create a paradox (like changing wives), the "parallel worlds" theory explains it: you create a new world, but the old world remains the foundation of your existence.
• For extreme attempts to maliciously destroy history, the "Time Patrol" provides a safety net, physically stopping you.

Fujiko F. Fujio used this approach, full of childlike wonder and imagination, to build a "gentle sci-fi world." He didn't get bogged down in hardcore physics laws but created a logical system serving the story's core themes of "love, friendship, and growth." This is perhaps one reason why Doraemon has become a classic spanning generations!