I am often of two minds about things, and sometimes that's on purpose. For example, I lost my ability to enjoy a good movie for a couple of years after I started doing audio post-production for film. I would get so focused on the sound that I'd miss significant chunks of the movie. Determined to reclaim my wayward enjoyment, I cultivated a meditational method of movie watching in which I'd acknowledge observations about the soundtrack and then let them out of my mind.
To provide an outlet for my urge to be the Central Scrutinizer, I would sometimes make an explicit decision before viewing a movie to study its sound and not worry about watching it. (This was generally for action blockbusters that offered little beyond spectacular effects.) Over time, it became natural and unconscious to watch the movie and occasionally make a mental note of some sonic occurrence.
This ability to divide your consciousness is critical in performing situations such as soloing over a sophisticated musical structure - part of your mind has to track the form while another part generates the creative statement to fit with it.
However, some conditions demand a physical separation in time or space, as opposed to a purely mental division. Consider the most double-cursed of performers: the drummer who knows how to set up the P.A. system. Drummer and actor Joe Paulino recently regaled me with war stories of frantically alternating setting up his drums with troubleshooting hums in the sound system right up until the downbeat, and then having to jump up from the drums to stop feedback. I endured similar circumstances many times - until the gig at which the mixer was 40 feet from the stage, and I was totally exhausted from running back and forth by the time downbeat came.
After that experience, I decreed to the band that we would have to shoulder the expense of a sound engineer because I couldn't continue to divide my energy. Even with a sound engineer, though, I still have to really focus sometimes to ignore sound problems that happen while I'm playing.
In fact, some situations can thoroughly challenge your ability to think on more than one plane. I recall the night that same band was onstage with the unflappable Mike "Scoop" Haeffelin mixing our sound, and one of the front-of-house P.A. amplifiers exploded into flame. Did I mention it was a tiny stage?
Now that was a circumstance that narrowed my consciousness to one choice centered on a more physical separation in space: whether to keep playing or jump the hell off the drums and either deal with it or just run away. (It also proved to be the only time I ever saw Scoop break into a full run on a gig, so I just kept playing and let him deal.)
Beyond carrying fire extinguishers to gigs, the most successful strategy I've found for managing split-role situations is to draw clear lines that separate and confine the roles. Often this involves setting a threshold: below it, you don't cross the lines between roles; above it, you do. (Let's face it, you can't always have separation.) For example, if a microphone is ringing, I keep playing. If the entire sound system goes into screeching feedback, I dive for the master fader (or, in the worst case, the AC power). It's not easy to decline to do something of which you're capable, but in the long run, your sanity may depend on it.
Unfortunately, not all circumstances yield to this approach. For example, you can't apply this method if you're engineering and producing simultaneously. A powerful unity can come out of doing both on a project, but engineering and producing can be heavy-duty jobs that are inextricably linked yet not the same.
At best, being able to function on more than one level gives me a richer experience and a broader perspective. At worst, it can be downright schizophrenic. Either way, recognizing the beast of duality is the first step toward taming it.