But those elusive parts are everything. A sentence written solely via some slide-rule calculus of readability will never be quite good enough. Writing has to be humanly messy, non-algorithmically flawed, to be truly readable. Something in us balks at the idea of applying algebra to words, because words, unlike numbers, can move, hurt, anger, enchant and cajole, and build credible worlds of thought and feeling out of nothing. That “little bit of creativity” is all. A sentence needs a glint of human intelligence behind it to give it the elusive thing, sentience, that makes it a sentence.