In A Tale of Two Cities, Book II Why does Sydney Carton love Lucie?Charles Dickens's A Tale of Two Cities

       I think it would be a good idea to refer to René
Girard's theory of "mimetic desire". It is assuredly of some relevance here because of
the strange relationship that exists between Sydney Carton and Charles
Darnay.

       As a matter-of-fact, René Girard's
interpretation of desire in The Violence and the Sacred rests upon
the idea that desire does not really lie either in the subject or in the object but that
it imitates another desire. Indeed, the subject models himself after another subject, so
that the sense of  rivalry turns the desire into an obstacle to be overcome and
eventually sought for.

      Consequently, in the case of
Carton, the frustration is due to his unconscious desire to be other which reveals the
desire to be and beyond the lack of
being.

      Thus, it is his passionate desire
and love for Lucie that turns the antagonistic (which largely results from their social
positions and the clash of interests it implies) into the agonistic (the exhilaration in
spite of or because of the pain, because of the suffering). His love becomes something
unparalled, unprecedented, unheard of.

      I think This
is probably why he loves Lucy.