Are you trying to convince yourself or someone else about the validity of an opinion you may now be defending? If you think that there is any chance that it is the former, and you are trying to prove to yourself that you are right about something, then you need to stop and consider the reasons why. Rather than wasting lots of energy defending your point, try to see why you feel you need to do that. It's okay to evolve into a new way of seeing things. In fact, it might be a great thing, Sagittarius.