Full Idea
The worst, most wearisomely protracted and most dangerous of all errors hitherto has been a dogmatist's error, namely Plato's invention of pure spirit and the good in itself.
Gist of Idea
The most boring and dangerous of all errors is Plato's invention of pure spirit and goodness
Source
Friedrich Nietzsche (Beyond Good and Evil [1886], Pref)
Book Reference
Nietzsche,Friedrich: 'Beyond Good and Evil', ed/tr. Hollingdale,R.J. [Penguin 1973], p.14
A Reaction
A landmark observation about the history of philosophy. Imagine if all the Aristotle had survived, but all the Plato had been lost.