Reading Whitmans epic - The Leaves of Grass recently; I was so struck by his language and it's similarity to Nietzsches that I suspected that he had been influenced or read him.
I celebrate myself, and sing myself
And what I assume you shall assume
Which sounds like a possible conception of the Uberman; and
Do I contradict myself
Very well then, I contradict myself
I am large, I contain multitudes
Which as an idea appears in Nietzsche.
Further, consider that both positioned themselves as bards and prophets.
But this appears to be not the case; but it does appears that both were influenced by the Transcendentalism of Emerson: the over-soul and his 'foolish consistency'.
But why is one taken to be a philosopher and the other a poet; when it appears that both were philosopher-poets?