Achilles and The Tortoise Paradox in Jujutsu Kaisen – How Gojo became untouchable

With the release of Jujutsu Kaisen season 2 episode 2, Gojo mentioned the Achilles and the Tortoise Paradox Satoru in the anime during his use of Infinity. During his mission to protect and escort Star Plasma Vessel Riko Amanai, he took on a bounty hunter, during which he displayed his abilities and gave an explanation for the same.

The episode saw Gojo and Geto making an acquaintance with Riko Amanai and Misato Kuroi. Following that, the two sorcerers decided to help Riko do all that she wanted to do before she was set to be assimilated. During this, the Star Religious Group put up a bounty on Riko, causing attackers to reach their location.

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Jujutsu Kaisen: What is the Achilles and the Tortoise Paradox?

Satoru Gojo as seen in the Jujutsu Kaisen season 2 (Image via MAPPA)

When Satoru Gojo was taking Riko Amanai to Jujutsu High, they were interrupted by a bounty hunter, who was after Riko. During the encounter, the bounty hunter made clones of himself and attacked Gojo. However, none of the attacks reached Gojo, as his Infinity protected him.

When the attacker was left confused about Satoru Gojo's abilities, he explained how his ability, Infinity, was based on the Achilles and the Tortoise Paradox. It was created by Zeno of Elea to explain his Infinite Halfway theory.

Satoru Gojo as seen in the Jujutsu Kaisen season 2 (Image via MAPPA)

As per the theory, when an object is moving from point A to point B, there is always a halfway point between the two points. Upon reaching it, another halfway point is created as the previous halfway point becomes the new point A. Thus, a new halfway point will be created between new point A and point B. As per the theory, this goes on infinitely, creating infinite halfway points.

This theory has been explained by the Achilles and the Tortoise paradox. In the paradox, Achilles is in a footrace with a tortoise, where the latter is given a headstart, allowing him to cover some distance. As per the Achilles and The Tortoise paradox, even if Achilles were to run faster than the tortoise, he would never be able to reach it.

Satoru Gojo as seen in the Jujutsu Kaisen season 2 (Image via MAPPA)

Whenever Achilles runs, he will always reach a point that the tortoise has already covered. However, by the time he reaches a position, the tortoise may have covered more distance. As per the Achilles and The Tortoise paradox, this can go infinitely, causing Achilles to never overtake the tortoise.

The same paradox has been used in Jujutsu Kaisen, as Gojo's Infinity never allows his opponents to reach him. While the ones who witness the ability in action may perceive the situation as Gojo having stopped his opponent's attacks, in reality, his ability helps him slow things down.

Satoru Gojo as seen in the Jujutsu Kaisen season 2 (Image via MAPPA)

When someone or something attempts to attack Gojo, the person or object happens to hit the Infinity between himself and them. Thus, upon coming in contact with Infinity, the person or object starts moving through Infinity. However, due to the convergence of an infinite series, the person or object is never able to reach Gojo, as new spaces keep getting created between them infinitely.

Thus, the Achilles and the Tortoise paradox was the best way for Gojo to explain his Infinity's untouchability.