Below is a draft new entry for a proposed 3rd edition of Thinking from A to Z I'm working on at the moment. Comments very welcome (and you don't need to use the principle of charity when reading this).
Principle of Charity
Interpreting arguments or positions adopted by others in the best possible light. Rather than setting an opponent’s pronouncements up as an easy target, or even a straw man, those who adopt the principle of charity look for the best case that this person could consistently be making rather than the worst. Adopting the principle of charity involves reconstructing and evaluating others’ arguments. Most everyday discussions are incomplete in many ways: speakers omit key moves, or don’t make their underlying assumptions clear, for example. Consequently, most contributions to a discussion are open to interpretation. Those who adopt the principle of charity will interpret, or at times reconstruct, another’s comments giving that person the benefit of the doubt, and thereby considering a stronger rather than a weaker version of the speaker’s or writer’s ideas. There is great value in this approach in that it forces the you to consider others’ challenges and arguments in their most plausible form, and in the process can be intellectually stimulating because it typically requires an act of creative imagination to recreate a strong argument from what might seem like a series of assertions. Of course, even when put in their strongest form, arguments may still be open to counterargument, or refutation. For example, in a debate about animal welfare, a speaker might argue that all animals should be given equal rights. One response to this would be that that would be absurd, because it would be nonsensical, for example, to give giraffes the right to vote and own property since they would not understand either concept. A more charitable approach would be to interpret the claim ‘All animals should have equal rights’ as being a shorthand for ‘All animals should have equal rights of protection from harm’ and then to address that. Someone who adopted the principle of charity here would be forced to think through the strongest form of this argument rather than be satisfied with an easily refuted (see refutation) straw man. There is no obligation to adopt a principle of charity, but it can be a good antidote to pedantry, knocking down straw men, and the kind of relentless negativity that clear thinkers are sometimes accused of. UPDATED BETTER VERSION HERE