I think, therefore, I am

(am I?)

I fear to think I'm here

conversation

(fills my head

there's no silence)

voices rant on

the eyes

they see

(do they see everything?)

(one) astronomer

(is a) moon starer

(two) astronomers

no more stars

(there were never any stars)

(now I'm)

older and wiser

I learned words

a perfectionist

I often practice

(it makes no difference)

(the words are still dying)

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A/N: Every stanza, excluding the words in parentheses, is an anagram.