Why was the first Jedi Temple built on top of a Dark Side cave?

Question

I am curious to know if there is anything mentioned in Star Wars canon that explains why the first Jedi Temple, located on the planet Ahch-To, was built on top of a Dark Side cave.

I personally can't see any advantage the first Jedis would gain by building their first temple at this particular location since any Jedi who would enter the cave would likely be tempted by the Dark Side and may then decide to follow a path that would lead them to becoming a Sith.

Why was the first Jedi Temple built on top of a Dark Side cave?

Answer 1

It would appear that the ancient Jedi weren't warriors of light, instead worshipping balance. That evidently included studying and possibly even embracing their dark urges. It was only in latter years that they became obsessed with taking sides, resulting in a powerful imbalance in the Force that led to the Sith Wars and, ultimately, the near-total destruction of the Jedi Order itself.

It seems likely that the site of the Temple was either chosen because it had a dark influence (noting that the Jedi temple on Coruscant was also built on top of an ancient Sith Temple) so that they could more readily explore the dark side of the Force, or simply that it had become imbued with dark influences as they explored their own Force talents.

_{^{A mosaic depicting the first Jedi meditating on balance, found on the floor of the temple at Ahch-To}}

Answer 2

The High Republic: Into the Dark explains that the dark side site below Coruscant was conquered from the Sith by the Jedi, and that they took dark side artifacts to it and used it to drain their dark side energy, guessing that it would then dissipate into the force in general.

We don't know the exact history of the first temple one, but it's worth remembering given the above that dark side spots aren't without their uses in depowering dangerous Sith artifacts.

Answer 3

To further support Valorum's answer, the concept of the Force was based on a mash-up of religious concepts surrounding an idea of "balance", the most obvious of which ties to the concept of Yin and Yang:

The principles of the Force resonate with those of some real-world religions, including the Shinto religion of Japan, Buddhism, Taoism and certain Celtic druidic concepts. [...]the splitting of the Force into light side and dark sides echoes the concept of yin and yang in Eastern philosophy [...] Along with the concepts of yin and yang, the concept of a ubiquitous Force parallels the real-world concept of a "Tao" or "way," which is said to flow everywhere in the universe.

Source

When we look at what the concept of Yin and Yang represent, we can see the relevance to how the Force is a sum of the whole, and the separation of the Jedi ("Light"), and the Sith ("Dark") moves away from what the balance should be (emphasis mine):

In Ancient Chinese philosophy, yin and yang (/jɪn/ and /jɑːŋ, jæŋ/; Chinese: 陰陽 yīnyáng pronounced [ín jǎŋ], lit. "dark-light", "negative-positive") is a concept of dualism, describing how obviously opposite or contrary forces may actually be complementary, interconnected, and interdependent in the natural world, and how they may give rise to each other as they interrelate to one another.

We can see this "yin and yang" symbolism represented in the image in Valorum's answer as well.

My original understanding was that the Jedi Temple being built on top of Sith caves and temples was to "Put a lid on it"; bury and smother it in a misguided attempt to bring balance to the Force, after the separation of the Jedi and the Sith, being that the Jedi believed that "balance" meant "snuff out the evil":

"The Jedi tried to cap the power of this shrine, but there's leakage. It's not just Sidious; it's the power of history, it's the residue of what's left of the dark side there."

―James Luceno

Source

Where the problem started with an "imbalance" of the Force was the separation of it, and the belief that the Dark side needed to be removed, or hidden must have been lost in translation, and buried in history.

So in summary, as Valorum stated, the original practices/studies of the Force embraced both "sides", as it believed in embracing all aspects, similar to the concept of Yin and Yang, but as the separation developed between the "light" and the "dark" sides of the Force, the desire to bury and hide any association with the "dark" side led to the Jedi cutting off, and hiding the associations the Jedi had with the "dark" side of the Force (i.e. the Sith Caves), which the original practitioners had built on (The Jedi Temple(s)).

Answer 4

Because it was Inevitable

A common theme in Star Wars is that the force balances itself. From what I recall, the movie does not make clear whether the temple or the cave came first, instead it strongly implies that where there is one, the other always shows up to oppose it. So, if the Dark Side cave came first, it would be inevitable that a Light Side presence would show up to oppose it, but it is just as likely that the Light Side temple came first, that the Dark Side cave emerged to bring balance to the force.

Answer 5

In order to ritualistically purify the space.

From Resistance: "The Relic Raiders"

Mika Grey: We're in an ancient Sith temple. Sometimes, you find them buried beneath Jedi temples.

Kazuda Xiono: Why would the Jedi do that?

Mika Grey: It's a purification of suppression.

Answer 6

Possibly not canon, but a logical answer:

1. The Temple Plug: The Sith were throwing off the balance in favor of the dark side. So 'plugging' a dark side source and concentrating on light side studies is in favor of balance.

2. Easy training ground: a contained, easily leavable site of the dark can be used as a dark side exposition training site. Building a temple of the light around it ensures the dark side energy can be contained and those who feel strains of dark side corruption can be treated quickly.

3. Control and advertising: The oh-so-balancing Jedi thought their belief is best, so they conquer and fortify their (energetically) strategic points all over the place. Much like McDonald's or StarBucks do, they sought advertising for the Force-interested, offering their services and local recruitment and training programs for Force-sensitive youngsters.