If we accept the scriptures as truthful, Either the Buddha believed and taught previous lives and rebirth, or the Buddha was a liar, I choose to believe in rebirth, and the Buddha(for the sake of arguement, I am considering acheiving Nibbana, and non rebirth as a form of rebirth in paranibbana, not a nihilistic ceasing to exist)
You can't have extended discourses about your past lives, and not belive in rebirth, do you think the Buddha just made up his past lives or was deluded about them?
I also disagree that's ones beliefs on rebirth do not effect ones practise, whether they should or not is another discussion. Belief in rebirth is a great motivator to practice the Path, believing there is nothing after death, is a great motivator to just give up caring about everything, and indulge the senses,
Just like Christians find a belief in Heaven and hell to be a great motivator to practice moral conduct, buddhists likewise do the same with rebirth, whether that is correct or not is not the question, but rather what is human nature, if you believe in an after life or after lives, you are more likely to let that influence you present behaviour and practice IMHO
18 years ago I made one of the most important decisions of my life and entered a local Cambodian Buddhist Temple as a temple boy and, for only 3 weeks, an actual Therevada Buddhist monk. I am not a scholar, great meditator, or authority on Buddhism, but Buddhism is something I love from the Bottom of my heart. It has taught me sobriety, morality, peace, and very importantly that my suffering is optional, and doesn't have to run my life. I hope to give back what little I can to the Buddhist community, sincerely former monk Johnhttp://trickleupeconomictheory.blogspot.com/