Clear and sweet is my soul, and clear and sweet is all that is
Not my soul.
This semantic construct, that P and not-P are the same, makes use of the principle of bivalence. Essentially, everything is clear and sweet for Walt Whitman.
The seemingly redundant statement serves a purpose, though, to put the soul at equal footing with the rest of the non-soul universe.
Whitman is saying that because his inner is clear and sweet, he through his eyes and his perception also sees the world, first of all nature probably, as being clear and sweet (/in harmony and beautiful and full of love). Depending on what’s the reality of our surroundings, and in my opinion and I guess also in Whitman’s the nature is really beautiful and in harmony, you could say, Whitman sees the world like it really is, for his soul is ‘clear and sweet’, what of course mostly comes along with having peace of mind (!).
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