To perceive good and evil is a thought process. One would look at the issues, analyse those issues and determine which value assessment to give them; good or evil.
On the other hand "to disturb the universe is to actively take part in changing or attempting to change some long held value or tradition. To disturb the universe is courageous and powerful in deed.
When Jerry decided not to sell the chocolates at the fundraiser, he was not trying to perceive if the fundraiser was good or evil, he was actively going against a long held tradition of the young men and staff of Trinity Academy. He was upsetting the thought process and perception of what everyone had been doing for years.
"It is important to understand that Jerry's boycott of the chocolate sale is at no stage based on a point of principle relating to the sale itself. To begin with he is simply acting in accordance with a Vigil assignment. Continuing the boycott beyond the ten-day assignment is an act of individual defiance which Jerry is unable fully to explain to himself. His individual stand arises out of the circumstances of his personal life—the recent loss of his mother, the apparent tedium of his father's existence as a pharmacist—and from his fascination with the poster hanging in his locker (with its quote from T. S. Eliot, "Do I dare disturb the universe?"). "