If you look at my previous reply to a question, you will see that I deal with the same issue in a less academic context.
If an author is making a point or taking a stand, then we should use the present. Thus 'While Thackeray mostly condemns the morals of his day, Dickens supports that morality, but is opposed to the double standards of those who pretend to enforce it.'
However, if you are describing a personal interaction with the text, you should use the past tense because that interaction happened in the past. For example 'Jones considers that Shakespeare used neologisms to make his audience consider their context, rather than due to a paucity of contemporary vocabulary.'
If you are simply describing events within the narrative, or a character, then it is usual to use the present, but not compulsory. However, if an event happened during a character's past in the novel then you must use the past. (E.g. 'Pip's adult character is affected by when he met an escaped convict while he was a boy.')