In A Christmas Carol, rationality and logic are pretty much big road blocks on Scrooge's way toward being a successful and fulfilled human being. Whatever Scrooge's emotional or psychological faults may actually be, they are outwardly shown by the way he dismisses the poor and the sentimental with the cold and heartless logic that Dickens attributed to the supporters of the New Poor Law and the newfangled science of economics. One of the main ways that we recognize that Scrooge has been cured is his sudden willingness to put himself in the hands of the Christmas Ghosts, and to give himself over to the supernatural irrationality and emotion they represent.
The poignant moments when he is trying his best to make sense of the wacky supernatural stuff going on while still trying to cling to his rationality are the places where we identify strongest with Scrooge.
No matter how much Dickens rails against rationalism, A Christmas Carol is totally a rationalist story; it throws the religious aspects of Christmas out the window and pushes for a more secular holiday based on kindness and generosity.