The Genius

Here is the first definition of "genius" in the Oxford English Dictionary: "With reference to classical pagan belief: The tutelary god or attendant spirit allotted to every person at his birth, to govern his fortunes and determine his character, and finally to conduct him out of the world . . . ." This idea that a person has a "genius," a personal guiding spirit, originated with the Greeks and was adopted by the Romans. Explaining why he stayed out of politics, Socrates referred to his genius: "it is a kind of Voice which, whenever I hear it, always turns me back from something which I was going to do, but never urges me to act. It is this which has always forbade me to take part in politics."

By Shakespeare's time the meaning of the word had expanded to mean, among other things, "characteristic disposition; inclination; bent, turn, or temper of mind" (OED). We no longer use the word in this sense; we're likely to refer to our "genius" simply as "me," as in the phrase "it just wasn't me."