Breaking this down from a spiritual sense with a little back ground.

Hello darkness my old friend
Darkness is the absence of Light (JESUS)

I have come to talk with you again
This is a conversation between the song writer and Satan. In many songs written then and still today, Satan has been involved in the process. RCA Motown and many other record companies do some serious witchcraft over every album master copy prior to running it for production. Look for john-todd-a-former-illuminatist-testimony on You Tube.

Because a vision softly creeping
In the Bible it states,Be self-controlled and alert. Your enemy the devil prowls around like a roaring lion looking for someone to devour. 1 Peter 5:8
Prowl-to rove or go about stealthily, as in search of prey, something to steal. Enough said.

Left its seeds while I was sleeping
The devil is a liar and he will tell you lies to cause you to disqualify yourself and try to get you to lose your identity in Jesus.

And the vision that was planted in my brain
Still remains
Within the sound of silence
Who said silence was golden? Silence is the lack of the voice of God. There was nearly 500 years between the old testament and the new testament. No voice of God. It was due to the priest not obeying the duties. All the people suffered.

Continued on part 2