Out of the four main adult influences in Pip's life who do you feel is the most important & influential in building Pip's character?
The four adults are Miss Havisham, Joe Gargery, Mrs. Joe Gargery or Magwitch ....
Great Expectations by Charles Dickens
While this question involves a reader's personal interpretation of Dickens's great novel, it is Magwitch who exerts the most influence upon Pip throughout the narrative. For, it is his appearance in the first chapter which initiates Pip's sense of guilt that haunts him throughout the narrative, and his desire for a father that cannot be fulfilled by Joe who is too servile to his shrewish wife. In addition, it is Magwitch who is the secret benefactor, generating Pip's "great expectations" and his journey to maturity as he goes to London, becomes educated, rencounters Estella and Miss Havisham, and eventually is converted from his selfishness and snobbery as he cares for Magwitch, who then effects Pip's adjustment of values.
Pip's guilt and social position
After he steals the food and the file for the convict, Pip is haunted by guilt, imagining that he hears voices accusing him. As he runs to the Battery, Pip feels as though he carries a load on his leg: "...the damp cold seemed riveted as the iron was riveted to the leg of the man...." In another chapter, when he sits with Joe at the Jolly Bargeman and he sees the mysterious man stir his drink with Joe's file, Pip feels guilty. Then, after his sister dies, Pip feels somehow guilty, "a shock of regret," and when he sees the old leg-iron from the convict as the murder weapon, his feelings of guilt are again attached to Magwitch.
Having assumed Magwitch's guilt, Pip also figuratively assumes his social position. He lives in a sordid apartment and is exposed to Newgate prison in the persons of both Mr. Jaggers and Mr. Wemmick. With Jaggers, who is described as setting traps Pip becomes a victim of his equivocations whenever he is summoned to his office. Even Miss Havisham tells Pip regarding his relationship with Estella, "You made your own snares."
Pip's search for a father
Because of his snobbery at having become a gentleman, Pip rejects Joe who visits him in London and fails to visit whenever he is near the forge. It is only after he listens to Magwitch tell his sad tale of being "in jail, out of jail, in jail, out of jail" and his exploitation by Compeyson, that Pip attains sympathy for the man of a simple nobilty. This sentiment then extends from Pip to Joe, who cares so deeply for him. Now free to be his father after Pip's sister's death, Joe welcomes the prodigal son Pip upon his return to the forge. From Magwitch, Pip has learned that true goodness and nobility lies not in wealth and titles, but in many of the poor, simple people like Joe and Biddy.
In his essay, "Imagery and Theme in Great Expectations," in Dickens Studies Annual, Robert Barnard writes,
It is through the use of this image [Pip as social convict] that we see most clearly that, as Pip takes over the same metaphor as the convict, he assumes his share in his guilt and emotionally comprehends his position in society. The child can both pity the convict and put himself imaginatively in his position. The young man with "expectations" and a horror of crime can do neither, which makes doubly ironical Magwitch's part in bringing about this change in character.