There is no orthodoxy in Wicca, but all branches share the belief that there is a unity to existance and that every living thing has a sacred spirit whose power can be drawn upon for various purposes.
These purposes are difined by their code of conduct which has been variously expressed as "Love, and harm to none", "Perfect love, Perfect trust" and "Love, and do what you will under the law of love".
The people who honour these principles are considered to be good witches and those who seek self-gratification or dominance over others are condemned by majority of practitioners as being corrupt.
The concept of there being black and white witches is a popular fallacy, in the same way as there are no wholly good or evil people.