I don't mean a total split personality.
From the movie "Memento": This explains it better.
Here's the truth: People, even regular people, are never just any one
person with one set of attributes. It's not that simple. We're all at
the mercy of the limbic system, clouds of electricity drifting through
the brain. Every man is broken into twenty-four-hour fractions, and
then again within those twenty-four hours. It's a daily pantomime, one
man yielding control to the next: a backstage crowded with old hacks
clamoring for their turn in the spotlight. Every week, every day. The
angry man hands the baton over to the sulking man, and in turn to the
sex addict, the introvert, the conversationalist. Every man is a mob, a
chain gang of idiots.
This is the tragedy of life. Because for a few minutes of every day,
every man becomes a genius. Moments of clarity, insight, whatever you
want to call them. The clouds part, the planets get in a neat little
line, and everything becomes obvious. I should quit smoking, maybe, or
here's how I could make a fast million, or such and such is the key to
eternal happiness. That's the miserable truth. For a few moments, the
secrets of the universe are opened to us. Life is a cheap parlor trick.
But then the genius, the savant, has to hand over the controls to the
next guy down the pike, most likely the guy who just wants to eat
potato chips, and insight and brilliance and salvation are all
entrusted to a moron or a hedonist or a narcoleptic.
The only way out of this mess, of course, is to take steps to ensure
that you control the idiots that you become. To take your chain gang,
hand in hand, and lead them.