I think you're kind of missing the point here. The whole 'Fact vs. Fancy' theme isn't to be taken literally. I know it's early in the year, but the reason why it sounds ridiculous in trying to explain it is because it is quite a ridiculous idea to begin with. Also, trying to explain symbols such as the light are far more effective and less awkward when you indicate the dichotomy behind it. And while I've forgotten all the quotes, for example...
"Throughout the novel, Sissy is described as 'bright etcetc', whilst Bitzer is described as 'pale etcetc'. By establishing a dichotomy in the radiance of these characters, Dickens suggests that the qualities embodied by 'Fancy' are benevolent, whilst those represented by 'Fact' are detrimental to one's life."
And while I did use a few 'big words', they're really not necessary. A (likely better) effect can easily be achieved even using simple vocab, to create a 'more elegant' sentence. I'm just too used to writing like this now to change =\