Quotes about abstraction

Edsger W. Dijkstra:

The purpose of abstraction is not to be vague, but to create a new semantic level in which one can be absolutely precise

José Ortega y Gasset:

The abstract is no more than an instrument, an organ, to see the concrete clearly.

Pablo Picasso:

There is no abstract art. You must always start with something. Afterward you can remove all traces of reality.

Saunders Mac Lane:

Good general theory does not search for the maximum generality, but for the right generality.