"Lately, my mind feels cluttered."
Yuki said looking tired.
"There's a lot of noise," Aoi answered.
"Noise?"
"Unnecessary information in the mind. When you can't distinguish signal from noise, you get tired."
Mira quietly approached and showed her notebook.
"S/N ratio"
"Signal-to-noise ratio," Aoi explained. "The ratio of useful to useless information."
"My mind might be full of noise," Yuki smiled wryly.
"It's okay. There are noise reduction techniques."
Aoi drew on the whiteboard. "First, you need to know the types of noise."
"Types?"
"White noise, pink noise, impulse noise. Each has different characteristics."
"Mental noise has types too?"
"It does. For example, constant anxiety is white noise. Sudden worries are impulse noise."
Yuki showed interest. "Each has different treatments?"
"Yes. For white noise, a low-pass filter is effective."
"Low-pass?"
"A filter that passes only low frequencies. Cuts high-frequency noise."
Mira drew a diagram. Frequency spectrum and filter characteristic curves.
"In terms of the mind," Aoi continued. "Accept the ever-present low-frequency anxiety, and cut the sudden high-frequency distracting thoughts."
"Accept?" Yuki was surprised.
"Trying to eliminate all noise makes you lose the signal too. You tolerate a certain amount of noise."
"That's profound."
"For impulse noise, median filters work well."
"Median?"
"Taking the median from multiple data points. You can ignore sudden outliers."
Aoi gave an example. "During a day, sometimes bad things happen. But overall, good things are more common."
"Median filter is a method to see that 'overall.'"
Yuki understood. "Don't get caught up in one bad thing, see the overall balance."
"Correct."
Mira showed a new note. "adaptive filtering"
"Adaptive filter," Aoi explained. "Changing the filter according to noise characteristics."
"Respond flexibly?"
"Yes. The same filter isn't always effective. Adjust according to the situation."
Yuki wrote in her notebook. "Mental organization also changes methods according to situation."
"Perfect. That's an adaptive mindset."
"But," Yuki asked. "How do you distinguish signal from noise?"
Aoi became serious. "Difficult question. Actually, there's no absolute standard."
"There isn't?"
"What's important differs by person. One person's signal might be another's noise."
Mira wrote. "Context-dependent"
"Context-dependent," Aoi nodded. "So first you need to know what's important to you."
"Clarify your values," Yuki understood.
"Right. That's the first step in designing mental filters."
"Prioritize, and process everything else as noise."
Aoi summarized. "Noise reduction isn't just technical. It can be applied to mental organization."
"Design filters. Adjust adaptively. And tolerate some noise."
Yuki smiled. "I feel a bit lighter."
"Good. Information theory also offers hints for living."
Mira finally wrote. "Perfect silence = no information"
"Perfect silence means no information," Aoi translated.
"Moderate noise might be proof of being alive," Yuki said.
"True. What's important is the balance between signal and noise."
The three quietly nodded. Mental noise reduction. It was life wisdom that information theory taught.