“We shall never learn to feel and respect our real calling and destiny, unless we have taught ourselves to consider every thing as moonshine, compared with the education of the heart.”
The wording is needlessly obtuse. I guess the writer was trying to impress the audience with his brilliance. He is obviously an ex-spurt (drip under pressure).
Moonshine is denoting something that is counterfeit, or not genuine. So basically you can't understand your real calling and destiny until you understand yourself - What motivates you? What do you like to do? What role do you like to play?