what function does benjamin serve in animal farm?

Benjamin is the "old wise man." He's more intelligent than anyone else on the farm including the pigs, but he doesn't let them know it. He talks very little and when questioned will turn the subject to age, experience, and the fact that when everyone else is dead and gone, he'll still be around. Benjamin's weakness is his apparent inability to act on what he thinks and believes. The other animals ask him for advice and he shies away from speaking; he loves Boxer and knows what will happen when he's taken away but doesn't do anything about it. He never fills the potential of what he could be; the good and wise donkey can't lead, so he let's the smart, bad pig take over.