Life is never certain... but then again, that doesn't mean we have to wallow around in uncertainty all the time either.
Now the saying above "When in doubt, get out of it" can have many meanings. Some people comments hinted that they saw it as "when in doubt, get out of the situation." That could be a job or relationship that makes you very unhappy.
But I have another meaning to that sentence.
"When in doubt, get out of doubt."
That means, when you find yourself in a state of uncertainty, go forth and discover 'certainty' (whatever that means to you). Explore your circumstances further, look within yourself deeper, ask others for guidance. In other words, get some answers to your questions. Quench your uncertainty with knowledge... so that you can make more informed decisions while traveling the road known as "Life".
Doubt is just a State of Mind... so hurry up and get across that border!
Keep the light on!