A Nichiren Buddhist debates a Tibetan Buddhist

Tibetan Buddhist: I believe in the non-dual teachings of the Lotus Sutra because emptiness does not work that way. We all are different, we are not equal. If all sentient beings were the same, one single teaching or scripture would be needed. I'm different from you -- I assume you would realize this now -- thus what you think is right for yourself is not valid for me, and vice versa.

Nichiren Buddhist: One can come to believe in the Lotus Sutra without changing a thing, at least initially. Just chant Namu Myoho renge kyo. Then slowly but surely your vision will expand and you will begin to see clearly. "This good excellent medicine now I leave here. You should take and swallow it. Do not worry that you will not be cured."(Lotus Sutra Chapter 16)

Tibetan Buddhist: The point of incarnation is to work out and purge the karma in a soul. 

Nichiren Buddhist: Since karma is infinite, having accumulated words thoughts and deeds since the infinite past, by your reasoning, it would take an infinite amount of future lifetimes to pay off one's karmic debt (in order to attain Buddhaood).

This is roughly the teachings of all Tibetan traditions. The Lotus Sutra, on the other hand, teaches that a "one to one" change of thought, word, and deed ignores the reality that the present moment encompasses both the infinite past and the infinite future. If the Teaching or Law is complete and final, the Teacher is supremely Enlightened, the faith or wisdom of the practitioner is profound, and the faith and practice is powerful, one will be able to manifest the karma of Supreme Enlightenment that has existed since the infinite past and suppress the karma of delusion (that has also existed since the infinite past). The ever more intense efforts to reveal one's innate Buddhahood while suppressing delusion from moment to moment creates the karma to attain Buddhahood quickly. Since the Lotus Sutra and teachings of Nichiren are very powerful (Namu Myoho renge kyo or Devotion To The Sublime Dharma of the Lotus Flower Sutra) and the Teacher has manifested Supreme Enlightenment since the infinite past (The Eternal Shakyamuni Buddha described in the 16th Chapter of the Lotus Sutra) the faithful practitioner will never fail to attain Enlightenment quickly, without having to spend lifetime after lifetime practicing the six paramitas, prajna [wisdom excepted]*. Furthermore, there are the concepts, "after expiating his sins" and "lessening one's karmic retribution" taught in the the Lotus Sutra (Chapter 20) and Nirvana Sutra that help to explain the powerful cause and resulting effect of a correct faith and practice.

When one is not yet near to having attained Buddhahood, one finds it difficult to believe that merely chanting the title of the Lotus Sutra with faith in the Eternal Buddha (Gohonzon) that we can quickly obtain Supreme and Perfect Enlightenment. Not close to Buddhahood, one sees karma as predeterministic. Tibetans, in particular, wrongly perceive that it is necessary to make one good cause for every bad cause because their teachings have no power to radically lessen one's karmic retribution. In other words, they wrongly perceive that bad causes in the past, in order to be expiated that now and in the future thay must make one good cause for every bad cause they made in the past,

Careful consideration will reveal that we can make sufficiently powerful good causes to overcome the effects of lesser evil causes as a shower of rain eliminates thousands of small fires. The most powerful cause possible is to chant Namu Myoho renge kyo and to teach it to others. 

Tibetan Buddhist: Unlike you, I think that Buddha thought about all the sentient beings that exist, and created suitable paths for each one of them. Buddhas do not discriminate. Some dialogue <snipped> and then the Tibetan Buddhist continues: As I mentioned, your writing reminds me easily of dualism. 

Nichiren Buddhist: Since it is true that Buddhas don't discriminate, they teach the same Buddha-vehicle (Lotus Sutra) to all beings. Your doctrines are dualistic: Many different teachings for many different beings. Nothing is more dualistic than that. If we are all Buddhas in essence there is only to teach the Buddha-vehicle. Even on a phenomenal level, do not all people thrive on air? Are not all people subject to the same physical laws such as gravity? All people have the capacity to benefit from a sufficiently profound teaching. Can you not envision a single great teaching to enable all people to become Enlightened? Namu Myoho renge kyo is that teaching. 

*Wisdom excepted because the Lotus Sutra itself is wisdom.