What is category theory and why is it trendy?

Everyone thinks that mathematicians like numbers. However, this is not entirely true. Mathematicians like precision, clarity and, most of all, understanding structure. The sole reason why people associate the subject with numbers is because we like quantifying things. But what is not so clear to the general public is that we don’t quantify for the fun of it, we quantify to understand, organise, define. Numerical values attached to a mathematical concept help us understand the concept better. They also help us group things together that have the same, or similar enough…