Dialectic

To him, the thoughts within his brain were not the more or less abstract pictures of actual things and processes, but, conversely, things and their evolution were only the realized pictures of the "Idea", existing somewhere from eternity before the world was. This way of thinking turned everything upside down, and completely reversed the actual connection of things in the world.



‎'For everyday purposes, we know and can say, e.g., whether an animal is alive or not. But, upon closer inquiry, we find that his is, in many cases, a very complex question, as the jurists know very well. They have cudgelled their brains in vain to discover a rational limit beyond which the killing of the child in its mother's womb is murder. It is just as impossible to determine absolutely the moment of death, for physiology proves that death is not an instantaneous, momentary phenomenon, but a very protracted process.'

http://www.marxists.org/archive/marx/works/1880/soc-utop/ch02.htm