Overall, the character of Silas demonstrates, through his vicissitudes, a series of moral philosophies.
First, life is never certain. No matter how well we do unto others, or how righteous our paths may be, we will forever be at the mercy of wrongdoers and evil. Our actions alone cannot save us. We need to be mentally, spiritually, and morally ready to withstand the circumstances that come our way.
Silas was a very naive man. His daily existence was at the mercy of outside influences: his church, friends, reputation in Lantern Yard, and relationship with his former fiancée. When his supposed best friend frames Silas and ruins his life, Silas is left a broken man. Rather than having the internal strength, the moral power, to lift himself up and go beyond his circumstances, Silas moves to Raveloe only to do the same thing: depend on outside factors for his happiness. This time, his work and his gold are his safety net. Yet, once again we see Silas falling apart when this, too, is taken from him.
His second fall was significant, however, in that he learned to connect with others. For the first time in years, he had to let go of his neurotic self-control and let the charity and care of outsiders enter his heart. It was his only way to survive the fall.
This leads to a second moral philosophy, which is that we need to experience love and companionship to learn to be better humans. As human beings, we have the responsibility of communicating and being open to interact positively with others. While meditation and solitude are ways to achieve self-love, the total isolation Silas maintained in Raveloe took away a lot of his humanity. People told rumors about him, he was misunderstood, and he always had an aura of unnecessary enigma.
Notice that, after the theft of the gold, Silas surrounds himself by those he shunned once and, for once, he allowed their compassion toward his pain to touch his heart. What the townspeople discovered was a very normal, loving man living behind his unique looks and quirky behavior. They learned to tolerate and accept Silas while he learned to open himself to others. He even became a loving parent to Eppie!
Therefore, had Silas not accepted love and companionship first, he likely would have never learned to give it. It is arguable that Silas felt love and companionship once in Lantern Yard; however, his life was more of a routine, and not a personal discovery, than it should be. Perhaps Silas had to endure those events in order to bring the true human out of him. That is the biggest moral philosophy in the entire novel.