These are not antithetical philosophies. These are three experiential states of the Yogi. Initially he is different from his Tutelary Deity. Dvaita. As he progresses in Yoga, he comes to know that he is a wave of that Ocean of Being Knowledge Bliss. Sat Chit Ananda Sagara. Visishtavaita. Again he progresses and becomes one with Deity Advaita. Dvaita is Bsc , V D is Msc n Advaita Phd