three vehicles ［三乗］ ( sanjō): A classification in Mahayana Buddhism of three kinds of teachings, each tailored to the capacity of a specific set of practitioners and enabling them to attain a state of awakening suited to that capacity. “Vehicle” means that which carries one to a destination or state of awakening. The three vehicles are the teachings expounded for voice-hearers ( shrāvaka), for cause-awakened ones (pratyekabuddha), and for bodhisattvas. The voice-hearer vehicle indicates the teachings that enable voice-hearers to attain the state of arhat by awakening them to the four noble truths. The cause-awakened one vehicle is the teachings that lead practitioners to obtain insight into the causal relationship and impermanence of all phenomena through the doctrine of the twelve-linked chain of causation or by observing the changes in the natural world. The bodhisattva vehicle leads bodhisattvas to near-perfect enlightenment and perfect enlightenment, the fifty-first and fifty-second of the fifty-two stages of bodhisattva practice, through the practice of the six pāramitās. Generally speaking, Mahayana Buddhism describes the two vehicles of voice-hearers and cause-awakened ones as “lesser vehicles,” or Hinayana, while emphasizing the bodhisattva vehicle.
The Lotus Sutra, however, declares that the sole purpose of a Buddha’s advent in the world is to enable all people to become Buddhas, and that the three vehicles are accordingly not ends in themselves but means to lead people to the one Buddha vehicle. It identifies the Buddha vehicle as the supreme vehicle that at once encompasses and transcends those three and leads all people to Buddhahood. The “Expedient Means” (second) chapter of the Lotus Sutra says, “The Buddhas, utilizing the power of expedient means, apply distinctions to the one Buddha vehicle and preach as though it were three.” It also says, “In the Buddha lands of the ten directions there is only the Law of the one vehicle, there are not two, there are not three.” T’ien-t’ai (538–597) expressed this idea as “the replacement of the three vehicles with the one vehicle,” a principle that he further divided into two—concise replacement and expanded replacement. The concise replacement of the three vehicles with the one vehicle is a reference to the short passage in the “Expedient Means” chapter that explains “the true aspect of all phenomena” in terms of the ten factors of life. This suggests that all life is endowed with the potential for Buddhahood. The expanded replacement of the three vehicles with the one vehicle refers to the section where Shakyamuni subsequently elaborates on the supremacy of the one vehicle from a variety of perspectives, using parables and other means to explain his meaning. This elaboration includes the latter half of the “Expedient Means” chapter through the “Prophecies” (ninth) chapter.