Through the portrayal of Doolittle, Shaw proves that poor man's coarseness in civility, depravity or inhumanity are not inherent but circumstancial.
In Pygmalion, George Bernard Shaw presents to us several admirable qualities in Liza's father, Alfred Doolittle.
a) Higgins notes that Doolittle has "a certain natural gift of rhetoric"; that is, he has an expressive way of speaking. Higgins feels that with a bit of training Doolittle could become a respected member of Parliament or a preacher.
b) Doolittle takes an interest in his daughter's morality. He tells how Liza sent him a message that she wants her personal belongings sent to Higgins' house, but "she didn't want no clothes." On this, Doolitle comments: "What was I to think from that, Governor? I ask you as a parent what was I to think?"
More importantly, Shaw has Doolittle explain to us that a man in his position "can't afford" to have the kind of morals that middle-class and upper-class people feel are proper.
As a member of the class he calls "the undeserving poor," Doolittle has the same needs for food, drink, and entertainment as anyone else, but he is never the recipient of charity from middle-class "moral" people. They would rather give their charity to some "deserving widow"--who has already collected from "six different charities in one week for the death of the same husband." As a result of his poverty, Doolittle cannot be blaimed when he tries to extort a few pounds from Higgins for "use" of his daughter.
He would like to marry his mistress, but she prefers to keep him as a courter who will shower her with presents.
All of this helps us to see that Doolittle's coarseness is primarily a result of his circumstances, not of his innate abilities.