Higher aims are in themselves more valuable, even if unfulfilled, than lower ones quite attained.

[Die höheren Forderungen sind an sich schon schikbarer, auch unerfüllt, als niedrige, ganz erfüllte.]

Johann Wolfgang von Goethe (1749-1832) German poet, statesman, scientist

Sprüche in Prosa: Maximen und Reflexionen [Proverbs in Prose: Maxims and Reflections] (1833) [tr. Saunders (1893), “Literature and Art,” #500]
    (Source)

(Source (German)). Alternate translations:

Aims of a higher order, even though they be not fulfilled, are in themselves more valuable than lower ones entirely fulfilled.
[tr. Rönnfeldt (1900)]

Higher demands, even unfulfilled, are in themselves more worthy of esteem than lower demands completely fulfilled.
[tr. Stopp (1995), "Posthumous," #1085]