No, I'm not familiar with modal logic; but I did take an intrest in fuzzy logic back in the 1990's. It's also a non-classical logic with qualifiers between 0 and 1.

If the air is very hot, then run the air-conditoner fast.

If the air is cool, turn air-conditioner **off**.

If the air is warm, then run the air-conditoner at normal speed.

etc ....

The more if .. then statements, the more intelligence.

Mathematics is vast. One of the challenges is staying focused in the area of interest.

Logic is the oldest link, as far as where mathematics stands with regards to philosophy. I understand why this modal logic might appeal to you, since it appears to get into enriching the language to capture some of the more subtle "human" qualifiers and metrics.

I am sure that I have had to defer a vast amount of material to the shelves just to remain as focused as i have these past few years. I am hoping to master some strong foundations so that, just in case I live to be much older, I might tinker around with physics with as strong a mathematical tool-kit as possible ... as an old man living on beans, almond butter, custom made flat breads and thin-crusted pizzas.

Just as Husserl employed the epoche to block out the entire world so as to focus on the "lifeworld" (representation of the world as phenomena), I must LIMIT THE CONTENTS OF CONSCIOUSNESS so as not to drown in a sea of chaos.

Eventually I wish to spend several years exhausting "Concrete Mathematics" (mathematical foundations of computer science), but I feel this devotion to the more abstract material to be a once in a lifetime opportunity; hence I am stubbornly keeping my attention focused on specific texts.

One of the challenges of remaining committed to this discipline is knowing where to start. It's quite personal, isn't it? I feel we are each on our own in coming to terms with just where we are at in our quest for mathematical maturity or even simply mathematical development. I would not be the one to discourage you from exploring what interests you.

I have left a trail as far as describing what interests me.