What advice does the alchemist give about listening to one's heart? do you agree or disagree?

The advice that the alchemist gives about listening to one's heart is that he encourages Santiago to listen to his heart so he will be on tune with the world and be able to follow his dreams.  Okay, i think i agree with him.
According to Alchemist; God created the natural world so people could understand that a more perfect world awaits, the natural world is to be used for spiritual teachings, a single grain of sand symbolizes the whole physical world and can lead to a vast understanding. 

The evolutionary adaptions to different environments are responsible for the variation in shape and function of the tetrapod forelimbs. It has been a common thing for organisms in the past to develop its certain body parts as an instinct to adapt the changes in its environment for survival.