The goal of Semantic UI is to narrow the divide between how we create meaning personally, through language, and how we construct meaning for computers.
Many programming languages treat logical and mathematical purity as their primary objectives, often ignoring that most of their human counterparts will never reach a zen like purely computational understanding of phenomenon in concordance with the machines they program.
Semantic UI is built around a very different premise, that the real bottleneck in computer programming are humans, and that the best way to advance the web isn't solely providing better institutions for learning programming, or even making more refined tools for existing programmers, but more importantly removing the technical barriers that separate programmatic meaning from human meaning.
Semantic UI is by no means a perfect library, many of the particulars are still being hammered out on a day-to-day basis, but it is my attempt to serve some of the ideas which I believe to be true.
Tell him, Cebes, he replied, that I had no idea of rivalling him or his poems (Aesop); which is the truth, for I knew that I could not do that. But I wanted to see whether I could purge away a scruple which I felt about certain dreams. In the course of my life I have often had intimations in dreams “that I should make music.” The same dream came to me sometimes in one form, and sometimes in another, but always saying the same or nearly the same words: Make and cultivate music, said the dream. And hitherto I had imagined that this was only intended to exhort and encourage me in the study of philosophy, which has always been the pursuit of my life, and is the noblest and best of music. The dream was bidding me to do what I was already doing, in the same way that the competitor in a race is bidden by the spectators to run when he is already running. But I was not certain of this, as the dream might have meant music in the popular sense of the word, and being under sentence of death, and the festival giving me a respite, I thought that I should be safer if I satisfied the scruple, and, in obedience to the dream, composed a few verses before I departed.
~from Phaedo