In which I mention a knife

1.

It is important to see this knife for what it is and not to be fooled into thinking that motorcycles or anything else are the way they are just because the knife happened to cut it up that way. It is important to concentrate on the knife itself. Later I will want to show how an ability to use this knife creatively and effectively can result in solutions to the classic and romantic split.

--Robert M. Pirsig, Zen and the Art of Motorcycle Maintenance: An Inquiry into Values

2.

The second principle is that of division into species according to the natural formation, where the joint is, not breaking any part as a bad carver might.

--Plato, Phaedrus, translated by Benjamin Jowett

3.
I also mentioned a knife here.