Asceticism is an extreme outcome of religious conversion. When it occurs, the individual finds pleasure in denying the self and the needs of the flesh to such a degree that the person may practice radical acts of self-discipline or self-denial, such as fasting, rejection of material goods, vows of celibacy, withdrawal from society, etc.

James describes conversion in detail in Lectures 9 and 10. Conversion is a type of rebirth or regeneration which occurs when a singular psychological aim redirects all others. James argues that conversion occurs either voluntarily or involuntarily. The human mind is driven by many motivators. These aims take turns, each pushing out the other. The act of conversion occurs when a divided self becomes unified through a singular aim—including, as in the subject of James’s lectures, a commitment to a religious belief. 

James takes a broad view of divinity. Rather than limiting his discussions to religions centered around a singular god, James asserts that divinity stands in for any type of primal truth. The individual enters a relationship with what they perceive to be absolute truth, and this truth is the source of the divine.