crich, it is definitely a good idea to keep in mind that all authors will have a bias, whether that bias was instilled due to religious influence or - as per your example with Dickens - events in their own upbringing. It's one of the things that keeps philosophy interesting
Take, for example, the John Ruskin book I cited earlier. While I found his alternative view of economics fascinating, I'm not about to buy into it verbatim. Ruskin was a man who believed in hierarchical structures ... and I guess I do too, to an extent, but Ruskin - being a man of his time - shows a definite skew toward a class system that accepts the rich as inherently smarter/better than the poor. Certainly he was compassionate enough to believe these richer/smarter/better/higher-class people have a responsibility to those less able, but there remained that implicit assumption that a person was rich/higher-class because they were more able - as if one led to the other (in either direction?). Or that's the way much of it read to me.
In more modern works of a philosophical nature it can be more difficult to identify the author's bias because we are more likely to share them. This is one of the things that makes reading philosophy both more interesting and more difficult: constantly reminding yourself to be critical (in the sense of thoughtful analysis) rather than merely accepting of what you read.