Journaling using Set Theory

October 10, 2026 • 0 comments

Image of a piece of paper written with a mechanical pencil, journaling about my day showing an example of using set theory in my journal entry. Fully discussed on his blog post KrisComputes (kc.kcuniversal.net)!

Journaling has been something I've done since this Gregorian year started—January 1, 2026. I can't describe, by words themselves, how grounding and therapeutic it has been. Actively doing it today, I learned about my daily life, my thinking and thought processes; how I manage certain things and also how I deal with happenings in real-time. My only regret with journaling is wishing I'd have done it sooner; had I done so during my youth and school days, I would've recalled, and uncovered, so many things. Not only that, I would've handled the stresses of school much better. Anyway, here I am, praising the task of journaling—doing it offline, using pencil and paper.

As the hot weather subsides here on the western side of the United States, remaining grounded, and hydrated, is the utmost importance. In fact, some of the happenings taking place this year, I actually thought happened last year; that's how quick things are moving and how fast I tend to forget. On the same token, I would write what's going through my mind, re-read, analyze, and often question why such thought(s) were even apparent. It's like having a conversation with yourself, in a way such that seeing yourself in a mirror, nor talking to someone else, can't interpret nor comprehend. I've developed a different, and new, kind of (self-)confidence that I never discovered; and also, having a bad habit of overthinking, journaling has given my mind a huge break, and relief, from the things I face. Because the benefits outweigh the risks, I can envision a global population so peaceful and quiet that everyone will sit and journal in public spaces. It'd be nice to have a future like that; and if that were the case, this mental health epidemic would disappear in less than a year.

Journaling couldn't have been taken to consideration without my lovely girlfriend. She was the one who hinted the idea to me back in 2024. In addition, various YouTube channels specializing in testing and reviewing stationaries, like pens and pencils, most of whom I subscribed to, really "influenced" me in pursuing the analog life. Now, yes, I own and still manage this blog, and our network website, but when it comes to personal growth, time for myself, and exploring my mind, days, way of thinking, I go offline. If anything, you can say that my posting and sharing on this blog, a sub-domain of my network website KCU Network, is the public stage, and journaling on notebooks and paper is my place of residence—not backstage. Credits to my girlfriend and all those YouTubers for continually sharing and posting about journaling.

If you, or anyone you know, isn't mentally "there," I would recommend journaling. Just being able to write your cares away is something that's needed, where there's so much information being pumped into us every minute of every day. The best part about doing this? As mentioned earlier, you manage your thinking better, shunning out things that don't serve your purpose; you know very well that some things, including some people, are not worth stressing over. Another thing with journaling is it's private. It's something you don't necessarily have to share online. It's a reflection, conversation, and reality check that only you can comprehend and understand; even if you do share it online, many people wouldn't get the gist nor would they care. For me, it's personal and not something that should be shared since it's only for you. However, given that I'm back self-studying mathematics, just for meu, I want to share a journaling technique that uses one of my favorite areas of math: set theory.

"The Sun Don't Set in Set Theory!"

I wanted to re-learn set theory; as I often learn math on my own time. Mind you, this isn't a journal about set theory, but using set theory techniques and notation in my journaling. While I'd rather not share the journal entries I wrote, for privacy reasons, I will recreate how I do this.

When writing about my thoughts, and how/why I process them, I'd prop them seperately into sets: one set of moods that are good and positive, then another that are ill-causing and negative. Check this out:

Let $t$ be an arbitrary thought I have/had, let $f$ be an arbitary feeling I feel/felt; let $G_{t}$ be the set of elements containing my good thoughts and let $G_{f}$ be the set of my good feelings. Additionally, let $N_{t}$ be the set containing elements of my negative thoughts and let $N_{f}$ be the set of my not-so-great feelings. While we're "letting," let $T_{p}$ be the set of all positive, humanly thoughts; let $F_{p}$ be the set of all positive feelings. Adding to it, let $T_{n}$ be the set of all negative thoughts; let $F_{n}$ be the set of all negative feelings. For that,

$$T_{p} = \text{the set of all positive thoughts}$$

and

$$F_{p} = \text{the set of all positive feelings}$$

And for the ones under "negative,"

$$T_{n} = \text{the set of all negative thoughts}$$

and

$$F_{n} = \text{the set of all negative feelings}$$

For example, one day, I'm having thoughts about doing good deeds—$t = \text{doing good deeds}$—and/or I have a moment where I'm feeling frustrated—where $f = \text{frustrated}$, then by notation,

$$t \in G_{t}$$ $$\text{given that}$$ $$G_{t} \subseteq T_{p}$$

because good thoughts are positive: becoming a subset of all thoughts that are positive. As for my negative emotions,

$$f \in N_{f}$$ $$\text{given that}$$ $$N_{f} \subseteq F_{n}$$

where my feeling of frustration, a negative feeling, is an element of my set of negative feelings: which is a subset of all feelings that aren't positive.

A "Set" Setting in Making Time for Yourself

Having done this, for the fun of it, tells me that it's possible—given that some thoughts and feelings are rather "fuzzy" and ambiguous—to group all possible, humanly feelings we experience and feel. It's too deep to talk and discuss about it here, but having done this for my journal, it helped sort out my thoughts and feelings into set notation. You don't have to do this, but I thought I'd share given my forever-interest in mathematics (if you're new here, I earned my mathematics BA in 2025; and have rekindled an interest in math since I was 22 back in 2009). I never had the intent in doing this, since it's a journal written in private and lay out what it is I'm thinking, what I'm going through, and what I need to let out, but having done this helped see a picture that I haven't seen—namely my own feelings in sets. Looking at it, if I wanted to, I can tally how many times I've had to enter in an 'element' into their rightful sets—I may just do so, actually. In that case, the more tallies I get on, for example, the sets $N_{t}$ and/or $N_{f}$, then I know something is wrong; whether that would be me, my circumstance(s), or something outside my control. I can't say what that might be, perhaps it's seasonal, home dynamics, personal matters, the workplace, etc., but that's what this would translate to. Furthermore, this can be a great technique tallying how your days are going. In fact, you can find patterns in how your days are going!

Once again, you don't have to employ this technique in your journaling. I just did this to "flex" my mathematical muscles even in my own, private writing. Given that I used set theory, plus the potential addition of doing numerical tallying on particular elements, shows this can be a potential—computational—project. Maybe someone out there has already done this, maybe someone is looking to optimize or research this. Not a problem given that plenty of us go through different feelings and thoughts every day. As you know, not every day runs the same way. If for some reason it is, then that's something to write about because not many of us go through the same thing. For some people, depression is more severe in the winter, but for others, it's their season of joy. Another example is someone is having a rough, tiring day; while someone else, somewhere, is having the time of their lives. It all rests on what one goes through, something only you will be able to understand via journaling. My usage of set theory mathematically helps me envision my thoughts and feelings better, and that's the message behind this blog post.

Just one last reminder: while you can use those tallies for sharing, either among someone you consider close, or online, I'd strongly suggest keeping your journal entries themselves private overall. No need to overshare online.