The song by Simon & Garfunkel that contains the line "Hello darkness, my old friend" is the 1964 song "The Sound of Silence". The song, originally titled "The Sounds of Silence", is a song that was written by Paul Simon over several months in 1963 and 1964. Audiences have specifically been told that the line "Hello darkness, my old friend" is a meme used to humorously express despair or existential angst.

In 1965, the song attracted real public attention in the US. This led Tom Wilson, the song's producer, to remix the track, overdubbing electric instruments and drums. The remixed version was released as a single in September 1965. Simon & Garfunkel were not informed of the song's remix until after its release. The song hit No. 1 on the Billboard Hot 100 for the week ending in January 1966. The duo had been broken up. They hastily reunited to record a second album, titled "Sounds of Silence" in an attempt to capitalize on the success of the single record. The remixed single song version was included on the follow-up album.

With "The Sound of Silence", Simon observed that the individual speaking is talking directly to "darkness", an old friend. The speaker is trying to encourage ordinary people to find meaning in their lives beyond commercial dealings. No one however is listening, except for darkness. The second line, "I've come to talk with you again," tells us that these nighttime conversations are habitual, further emphasizing the speaker's status as an outcast.

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