A lamp is lit above his head, and by its light he sees from one end of the world to the other. As the child is born, however, the angel strikes him on the mouth and he forgets all that he has learned and is born a simple and unlearned baby. A lifetime of hard work learning Torah and working on one's personality will constantly release, bring to consciousness, innate wisdom. A sensitive individual will feel intimations of his or her own deep intuitive level often. And that inner sense of inspiration provides the motivation, the source of optimism and confidence that genuine achievement is possible, even assured, if the necessary effort is made.
Children believe that they can become anything.
However, later in life one is lucky to have any inspiration left at all. But the idea is as we have described above. First comes a phase of unreal positivity, a charge of energy. And then life challenges one to climb back to real achievement independently. Many ba'alei teshuva experience an unexpected and disturbing letdown.