Your dad does have a point, which has been raised here a few times. I've tried to argue against it, but eventually I had to concede it. When you PhotoRead a book, it is percieved at an other-than-conscious level, so the emotions hit rather hard and the truth-detection mechanisms don't aways come into play.
My advice is to syntopically read ANYTHING that is remotely contriversial to you. For example, if you believe that all toast is evil, reading any pro-toast books on their own may have a "brainwashing" effect. If you're going to read books on toast, make sure you balance it with some anti-toast books in order to help you stay true to yourself. Also, if you get very mad while PhotoReading a pro-toast book or just after PhotoReading it, ACKNOWLEDGE that feeling as genuine and valid. Don't suppress your feeling as being prejudiced or wrong. If you change your mind after activating the pro-toast material, that's all right...
