En Sí: In and of Itself

On the Venezuelan shore, Francisco expresses his deep appreciation for the wild, natural beauty of his surroundings. In front of the camera, Francisco hesitates a few times, but it's not from lack of conviction. He's simply buying time to find the right word. For example:

Los arrecifes... la... la... el fondo marino en... en sí que es demasiado increíble.

The reefs... the... the... the ocean floor it'... itself is too incredible.

Captions 7-8, Playa Adícora - Francisco - Part 4
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One might take pause upon hearing en sí because those two words separately can mean "in" and "yes." But sí with an accent over the i is not just an affirmation; it's also a reflexive personal pronoun (short for sí mismo / sí misma) meaning himself, herself, itself, oneself, yourself (as in the formal usted), yourselves (ustedes) or themselves -- depending on the context.

Lo leyó para sí misma.
She read it to herself. [not out loud]

Cada uno debe hacerlo por sí mismo.
Each person has to do it himself or herself.

Solía pensar por sí mismo; no era influenciado por los tan llamados expertos.
He used to think for himself; he wasn't influenced by the so-called experts.

¡Venga y compruébelo por sí mismo!
Come and check it out for yourself!

Let's look back at our original example and home in on the idiom en sí, which means the same thing as en sí mismo (English translations: "in itself" or "in and of itself" or simply "itself").

El trabajo en sí no era interesante, pero le daba la posibilidad de viajar.
The job itself wasn't interesting, but it gave him the opportunity to travel.

Amor es bueno en sí naturalmente,
Love in itself is naturally good,
[from Juan Boscán's Sonnet, a sixteenth century poem]

You will also find it interesting to note that volver en sí, which we might be tempted to translate as "to come back to one's self," is an expression that means "to regain consciousness / to come to." It can also mean "to come around," as in "to realize the truth."

Si no vuelve en sí pronto, debemos llevarlo a un hospital.
If he doesn't come to soon, we must take him to a hospital.

Por suerte volvió en sí y se dió cuenta que era una locura.
Luckily he came around and realized it was a crazy idea.