The four stages of the path to enlightenment in Buddhism are the stages of the virtuous (三贤位), the four roots of goodness (四善根), the path of seeing (见道), the path of cultivation (修道), and the path of no more learning (无学道). The last three stages are collectively known as the stages of the noble path.
The four fruits of the Sramana in Buddhism are Srotāpanna (须沱洹), Sakṛdāgāmin (斯陀含), Anāgāmin (阿那含), and Arhat (阿罗汉). These fruits are achieved based on the number and nature of defilements eradicated by the practitioner.
The 'four pairs and eight levels' refer to the four fruits of the Sramana and their preparatory stages, which are further divided into eight levels. Each fruit has a preparatory stage (相) and a resultant stage (果), making a total of eight levels. This structure is used to classify the progress of practitioners on the noble path.
In early Buddhism, the process of enlightenment involves the stages of faith, understanding, practice, and realization (信解行证). In Mahayana Buddhism, these stages are elevated to the level of achieving Buddhahood, as described in texts like the 'Dizang Zhancha Jing,' which introduces the concept of 'four perfections' for becoming a Buddha.
The term 'Srotāpanna' (须沱洹) means 'stream-enterer,' indicating that the practitioner has entered the stream of the noble path and is no longer an ordinary person. This stage involves the first 15 moments of insight, with the 16th moment marking the attainment of the Srotāpanna fruit.
The 'seven births' refer to the minimum number of times a Srotāpanna practitioner must be reborn in the human or heavenly realms before achieving liberation. This concept is derived from the nature of the Srotāpanna stage, where the practitioner cycles through these realms seven times before final liberation.
The term 'Anāgāmin' (阿那含) means 'non-returner,' indicating that the practitioner will no longer be reborn in the desire realm. Instead, they will be reborn in the form or formless realms, having completely severed ties with the desire realm.