Philosopher Paul J. Ennis relates to Rust, and expounds upon the distinction between the two in an interview with Vulture:

I consider myself just a brute “realist” in the classic sense of seeing the world in a very blunt, cynical manner. However, in academic philosophy the term realism has many different senses and, to avoid confusion with them, pessimism is used as an alternative.

One thing this series makes clear is that pessimism and realism are not one and the same, regardless of how bad the world may be. One thing Pizzolatto wanted us to see with Rust’s mini-revelation at the end is that pessimism is no less of a self delusion than the religious optimism Rust rips apart.

This gets at something at this show’s core, something alluded to earlier by Rust: if life is really just what we make of it, our entire life is defined by the stories we sell to ourselves. This definitely has real life implications, but the meaning is enhanced when you realize we are learning this via television – a medium based entirely in storytelling.

I think what True Detective keeps telling you, over and over again, is that everything’s a story. Who you tell yourself you are, what you tell yourself what the world is, an investigation, a religion, a nihilistic point of view – these are all stories you tell yourself. You need to be careful what stories you tell yourself.

– Pizzolatto

Episode 3, “The Locked Room”

https://www.youtube.com/watch?v=_RfUj09pWfM

This line proves prophetic, because (SPOILER) despite the fact the “Yellow King” is caught, the larger conspiracy goes unsolved. No one even investigates the Tuttle’s involvement in the killings or the other masked men, so the case as a whole goes unsolved.

Nic Pizzolatto revealed that this line is also much more deep and meta than that, though:

“Now, think about all the things Cohle is talking about. Is he a man railing against an uncaring god? Or is he a character in a TV show railing against his audience? Aren’t we the creatures of that higher dimension? The creatures who can see the totality of his world? After all, we get to see all eight episodes of his life. On a flat screen. And we can watch him live that same life over and over again, the exact same way.”

Rust must have been a big fan of Thomas Ligotti, since this quote is eerily similar to Ligotti’s book The Conspiracy Against The Human Race:

human existence is a tragedy that need not have been were it not for the intervention in our lives of a single, calamitous event: the evolution of consciousness—parent of all horrors

While some have accused Pizzolatto of plagiarizing from Ligotti amongst others, he insists that he is simply making an allusion to his work, and the similarity was intentional:

In episode one there are two lines in particular (and it would have been nothing to re-word them) that were specifically phrased in such a way as to signal Ligotti admirers.

Another quote similar to The Conspiracy Against The Human Race:

“We know that nature has veered into the supernatural by fabricating a creature that cannot and should not exist by natural law, and yet does.”

Marty originally interprets this as Rust saying he should not have survived after losing so much blood. But Rust reveals this speech runs deeper than that, and there is a lot more to existence and “being here” than doing enough not to die.

And same as Rust Cohle in his interrogations. Part of why Rust is such a good detective is he understands the psychology of criminals. Rust sells these criminals the same cathartic narratives as a preacher or shrink, and is able to get them to confess more often than not.

https://www.youtube.com/watch?v=YFy8b-DXwH8

The very sermon that Cohle is critiquing, he employs all the same tactics in his interrogations

– Pizzolatto