Sujata asked, “World-Honored One, the Buddha has said that there are two kinds of bodhisattvas, the lay ones and the ordained ones, and that there are three kinds of bodhi (enlightenment): that of the śrāvakas, pratyekabuddhas, and Buddhas. If one who attains bodhi (enlightenment) is called a Buddha, why is it that śrāvakas and pratyekabuddhas, who also attain bodhi (enlightenment), are not called Buddhas? If one who realizes the Dharma nature is called a Buddha, why is it that śrāvakas and pratyekabuddhas, who also realize the Dharma nature, are not called Buddhas? If one who has all wisdom is a Buddha, why is it that the śrāvakas and pratyekabuddhas, who also have all wisdom, are not called Buddhas? All wisdom denotes the Four Noble Truths.”
Excerpts from A Discourse on the Sūtra on Upāsaka Precepts
Venerable Xiao Pingshi
Even if the sound hearer arhats and the solitary realizer pratyekabuddhas have realized the Dharma of Two Vehicles, all of them have merely realized the Path to Liberation. They have not realized the Dharma pertaining to the ultimate reality of the dharma realm, so they are limited to the Dharma of the Path to Liberation.
On the other hand, the Mahayana Bodhi can be attained not only by learning the Path to Liberation but also by seeking enlightenment so as to experience the ultimate reality mind of the dharma realm, the tathāgatagarbha, to personally witness and observe that all dharmas derived from the tathāgatagarbha entity and based on it, and thereby directly and indirectly connected to it, were indeed brought forth from the tathāgatagarbha.
The notion of “dependent arising without an intrinsic nature” cannot exhibit and validate the ultimate reality of all dharmas because its existence also relies on the tathāgatagarbha. Thus, it is definitely not the ultimate reality.
The Two-Vehicle practitioners do not understand the ultimate reality, so they also do not understand the Buddha Bodhi. This is the most significant difference between the Two-Vehicle Bodhi and the Buddha Bodhi.
A Discourse on the Sutra on Upasaka Precepts, Vol. 2, pp.53-54