Accepting Suffering
Philoctetes as a character is the representation of suffering. As an old satyr, he is no stranger to experience. In fact Philoctetes has a pain in his foot which he has long since stopped believing could heal. He accepts that this pain is his to bear, although it detracts from his energy. For example he cannot teach Neoptolemus about Heracles' bow because he is caught by a fit of intense pain. He misses some opportunities, but he doesn't complain. Philoctetes' experience has taught him gratitude in the midst of pain so that, despite his personal suffering, he does help Odysseus and Neoptolemus. His sacrificial journey to Troy is eventually rewarded by the healing of this incurable wound.
Individual Good vs. the Collective Good
This is the major question of the book and a prominent theme throughout. Odysseus, Philoctetes, and Neoptolemus are all asked respectively to make a judgement call regarding their own ethics or those which serve the larger group. For Odysseus, this decision looks like deciding how to best serve his goal of sailing home or his instinct to protect his friends. He makes a difficult call and challenges his friends to continue helping him. For Philoctetes and Neptolemus, the collective good wins out. They sacrifice their more pressing desires or benefits in order to invest in some service to people beyond their current vision. Most notably, Philoctetes agrees to travel to Troy, despite knowing he will be oppressed by the Greek army.
Investment in the Unknown
In order to even approach Philoctetes, Neoptolemus must be convinced that his future reward will be good. He is not thrilled to deceive Philoctetes, so Odysseus persuades Neoptolemus that this one sacrifice of personal ethics will lead to both of their benefit in the future. Odysseus convinces Neoptolemus that he is ultimately pursuing honor. While Neoptolemus doesn't necessarily believe this, he does agree to take a chance. He consciously chooses to approach Philoctetes on Odysseus' behalf and winds up engaging in this adventure and finding Heracles' bow.
