
Corin is the Forest of Arden's native voice of pastoral experience - his practical help secures Rosalind and Celia's cottage, and his debate with Touchstone gives the play's country-versus-court theme its clearest direct expression.
Corin is an old shepherd native to the Forest of Arden, first seen listening patiently to Silvius's lament for Phebe and offering the mild, experienced observation that he too once loved this desperately, though he cannot now remember the particulars well enough to give useful advice. It is a small, warm joke about the difference between the intensity of young love and the softened memory of old age, delivered without any bitterness.
When Rosalind and Celia arrive exhausted and hungry, it is Corin who provides the practical information that gets them settled - his master's flock and cottage are for sale, since his master is 'of churlish disposition' and cares little for hospitality, and Corin brokers the purchase that gives the disguised cousins a home in the forest for the rest of the play.
His most substantial scene, a debate with Touchstone in Act III over the relative merits of court and country life, gives the forest's pastoral values their most direct articulation and their most direct challenge - Corin defends a shepherd's contented, self-sufficient existence with plain good sense against Touchstone's citified wit, and neither party fully concedes the argument, which is rather the point: the play is not interested in declaring one life definitively better than the other.
Corin is motivated by a settled contentment with rural life and a practical helpfulness toward the strangers who arrive in his forest, offering what assistance and wisdom his long experience as a shepherd affords.
Corin represents the forest's genuine, unglamorised pastoral life, in contrast to the more theatrical version the exiled court sometimes performs - his contentment is real and hard-won rather than a philosophical pose, and his debate with Touchstone shows a man entirely secure in the value of his own experience.