Lyric discussion by Daemian 

This song is about Maynard delving into the painful memories of his past which he has repressed "I've been picking scabs agian", this is represented in Jungian Psychology as his "Shadow", in order to grow and overcome there effects on him. The shadow in this song is the same as the Snake in H "my shadow's shedding skin", which represents urges to treat Devo how his father treated him, abusively. In order to eliminate his shadow he must first elucidate it's comments by looking into what he has repressed in his shadow. The song shows this metaphorically through getting in touch with past uses of his body.

I'm down Digging through My old muscles Looking for a clue

I've been crawling on my belly clearing out what could have been

 The lyrics may also imply that he's been analyzing his dreams to further elucidate these repressed thoughts and feelings "wallowing in my own confused and insecure delusions" also "chaotic and insecure delusions" all to find and bring out these unconscious fears, and urges. 

for a piece to cross me over or a word to guide me in I wanna feel the changes coming down I want to know what I've been hiding

In my shadow

 The last 2 verses of this song are merely a declaration that he will do whatever is necessary, lie, cheat, steal, love, kill, die, etc. to express his shadow and by doing so understand it, and bring it into consciousness.
 He is throughout this song attempting to bring his "shadow" into light, merging it with his consciousness.  When he has merged his unconscious fears and urges with his conscious psyche "stepping through (his) shadow" he will have gained understanding of why he feels the way he does towards Devo, and these feelings will no longer be unconscious urges, effectively evolving (but in a psychological way) which is what the line and title "Forty Six and 2" represents metaphorically. Or at least that's what I got out of it.

On a related note: THIS SONG IS AWESOME

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