Sunny glanced at the old scientist with interest.
"Causality? Do you mean its reason?"
Professor Obel smiled.
"No, nothing so philosophical! What I mean is that we are exploring the cause and effect of various phenomena having to do with the Spell, as well as correlations between them. Of course, our study mainly has to do with the Nightmare Gates, but since nothing exists in isolation, we need to consider the system in its entirety."
Sunny considered his words for a while.
"Is this how you make the Obel Scale work?"
The old man shook his head with an amused look.
"That thing? No, not quite. The so-called "Obel Scale" is a primitive work that I and many talented colleagues of mine created in the early days of the Spell. It is relatively effective for what it is supposed to do, but the solution is purely practical. It can track and predict manifestation events, but does not shine a light on how and why they are happening.
Back then, we had no time to ponder such things. We needed to come up with an immediate and effective measure, limited as it might be."
He sighed, and then said in a wistful tone:
"You see… a caveman can observe lightning and know that being hit by lightning is dangerous. Therefore, he can learn to recognize the signs of an approaching thunderstorm and take shelter from it. However, without understanding the principles of why and how lightning appears, a caveman cannot invent a lightning rod, build a Faraday cage, or harness the power of electricity.
So, that is how our work here differs from the "Obel" Scale. That old solution is simply a tool to recognize the signs of a thunderstorm and assign a numerical value to the probability of lightning striking a particular spot, while we are trying to understand its principles."
Sunny listened to the elderly scientist attentively. When else would he get a chance to converse with someone so learned and knowledgeable? Luckily, Professor Obel seemed to either be fond of educating young people in general, or was simply in a talkative mood.
Deciding to use this chance to learn something new, Sunny asked:
"How does the Obel Scale work, anyway?"
The old man chuckled.
"Ah, it's not too complicated. You are familiar with a pulse that the manifestation of a Nightmare Gate produces, right? Depending on the Category of a Gate, it differs in potency and characteristics, spreads over a certain radius, and affects a certain volume of space. The more powerful the Gate, the greater the impact."
Sunny tentatively nodded, prompting Professor Obel to give him a small smile.
"Well, in truth, that pulse is a bit more complicated than that, because it spreads not only through space, but also through time. So, if we know what to look for, we can detect faint aftershocks of a Gate impulse before it actually appears.
Of course, that requires a vast and expensive network of sensors and monitoring satellites to monitor the entire globe, or at least those areas that we deem important."
Sunny blinked.
"Uh... what exactly do you mean when you say that the impulse spreads through time, Professor?"
The old man looked at him and remained silent for a few moments.
"How do I put it… try to imagine time as a river, young man. It always flows forward, from the past into the future, and we travel forward with its current. Now, imagine that someone threw a rock into that river. There would be ripples on its surface, wouldn't there? And those ripples, unlike the waters of the river itself, would travel both downstream and upstream. Hence, we can detect those ripples.
From a bit further up the stream."
Sunny couldn't help but scratch his head. What Professor Obel said was not hard to understand… however, it was a bit harder to accept.
'Perhaps if I think about it in a different way…'
Sunny imagined a string of a harp. Someone plucked it in the middle, sending a vibration spreading both up and down. Downward was the future, and upward was the past.
Then, he imagined the inconceivable tapestry of Fate, and the neverending expanse of its countless strings, each stretching from nowhere to infinity. A certain event happened, making small sections of several strings tremble.
Was that what the old man was talking about?
A subtle frown appeared on his face.
'Come to think of it… does affinity to revelations, perhaps, work based on the same principle?'
Sunny hesitated for a bit, and then cautiously said:
"I… I think I understand? Maybe."
Professor Obel smiled.
"Good! However, as I said, this is just a primitive solution. That solution only observes the effect without understanding the cause. And the cause… why, it is much harder to comprehend. Truth be told, I don't think that humans like us can even conceive of it in its entirety.
In fact, the predominant school of modern thought states that the Nightmare Spell is acausal by nature, meaning that it does not even adhere to the principle of cause and effect. That it's magic, so to speak."
He grimaced.
"I don't agree, obviously. But, anyway, trying to understand even a little bit of the causality of the Spell is a daunting task, so we limit the scope of our research to a small fraction of it… namely, the Nightmare Gates."
The old man's face darkened a little.
"...However, even that has proved to be an insurmountable task, I'm afraid. For now."
Sunny raised an eyebrow.
"How so?"
Professor Obel smiled bleakly.
"Oh… well, to be honest… this might sound funny to you… but we are not even sure that Nightmare Gates have anything to do with the Nightmare Spell…"
He seemed to have expected to be rebuked, but Sunny did not react to that statement too much. Instead, he thought for a bit, and then asked calmly:
"Really?"
The old man looked at him with a bit of surprise.
"You are not against that idea?"
Sunny shrugged.
"During my Second Nightmare, I was separated from the Spell for a while. I couldn't summon my Memories, visit my Soul Sea, or even hear its voice. However, my Aspect and powers were still with me. So, I figured that Aspects, at least, exist outside the Spell. If Aspects are their own thing, why can't Nightmare Gates be? Oh… that doesn't mean that I'm convinced, though.
I am just open to the possibility."
Professor Obel looked at him with gleaming eyes.
"Separated from the Spell? Fascinating! Young man… please, do share your experiences with me later."
Sunny grinned.
"No problem. However, if you do publish something as a result… I'll be entitled to receive some points, right? You know, as a contributor."