Source: p 7 of 35, Citizenship in a Republic (a speech), by Theodore Roosevelt
One notable passage on page seven of the 35-page speech is referred to as "The Man in the Arena":
It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who neither know victory nor defeat.
For brevity, I denote this 'man in the arena': lionheart. I guess that but serves as a conjunction here. Yet which definition applies? No 'contrast' (Defn 1 ), 'impossibility' (Defn 2), or 'a response expressing a feeling such as surprise or anger' (Defn 3) exists, seeing as the preceding relative clauses are already exalting this lionheart. So why use but? What would change if but were omitted?
Footnote: I was reading this when I lighted upon this passage.