Samadhi and Prasrabdhi

In the access concentration, the state of serenity can arise, while samadhi is a meditative state that appears in concentrations at or above the first dhyana. Access concentration does include serenity, but it differs significantly from the serenity of the first dhyana; the first dhyana feels almost like a celestial being. The serenity in access concentration is slightly less profound, and the body may exhibit phenomena such as feeling tall, massive, light, or floating. One walks briskly, feels uplifted, experiences overall bodily lightness, moves silently, and maintains inner tranquility. Even within the same level of concentration, the physical and mental states vary among individuals. Similarly, the same person may display slight variations in different sessions. The states of desire-realm concentration also come in many forms, with differing depths of concentration. Even within the same first dhyana, each person's physical and mental experiences and states are not entirely identical. Moreover, when the same person enters the same concentration at different times, their physical and mental states and sensations are not completely consistent.

Even the same term "serenity" has different defining boundaries and varying degrees of manifestation. It is impossible to strictly determine the exact threshold of serenity, as each person's definition may differ. If someone lacks mental equanimity and insists on debating this, each will simply stick to their own view. Strictly speaking, samadhi should occur in concentrations at or above the first dhyana; this is the formal meditative absorption, the foundation of the four dhyanas and eight samapattis.