This is a very interesting question! Usually in criticism of novels, external conflict is directly plot oriented; while internal conflicts within characters may or may not affect the plot. It is one of the subtleties of the "The Namesake," that here internal and external conflicts overlap in interesting ways.
An obvious external conflict is the conflict between the two generations -- the parents' and the children's. It's a conflict that those of us who have brought up children in the US have experienced in more or less the same way as Gogol's parents: Ashoke and Ashima.
Throughout the novel, the parents try to "make" their children Bengali while the brother and the sister, Gogol and Sonia, insist that they are Americans. The conflicts have to do with everything from giving the children their names, to whether or not they should make periodic visits to India.
Symbolically, this external conflict of the generations is brought about by the direct conflict between Ashoke, the father and...
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