The dialectical opposition between Smith and Neo in The Matrix film is a strong indication of what their respective characters represent. Smith is pitiless and single-minded, focused on finality, conformity, purpose and inevitability. As such, Smith represents determinism.
By contrast, Neo, with his unpredictable, emotional human nature, represents unbounded free will and the power of choice. Neo’s solitary role as The One is contrasted by Smith, who, by replicating himself, becomes ‘the many’. When Neo asks the Oracle about Smith, the Oracle explains that Smith is Neo’s opposite and his negative.