Previous definitions are good, but miss out on one thing.
the "I and I" also marks a distinktion between the body (that which can be seen) and the spirit. This is reinforced by the similarity of sound between "I and I" and "eye and I".
The expression "I and I" thus expressedly includes all of ones being.
Also it can be used straight of as a possessive pronoun.
"I an I donlike it!";
"Is tha fe I an I?";
"It belongs to I and I".
Also means "I, with God's help" or "I, with God-in-me". Often used in place of "me". Because the people's Identity was destroyed in slavery, Identity is very important in RastafarI -- so I gets capitalIzed a lot. They pronounce the I's strongly in reggae songs. Emperor Haile Selassie I is not "the First" but "Haile Selassie *I*."
Zeta Reticuli I and II form a star system which is supposedly the home to Zeta Reticulins, a race of aliens commonly referred to as the Greys. This system was first mapped out by Betty and Barney Hill after an abduction and thought to be fake but was discovered by astronomers as real in 1967. This star system is key evidence as proof of alien existance.