The Samkhya system of Indian philosophy regards Matter (prakṛti) as continuously evolving because of the dynamic interplay between the three elements or guṇas that constitute it—namely, sattva, rajas and tamas. According to this philosophical system, the psychophysical apparatus of individual beings (jīvas) is a product of Matter and therefore constantly changing. Change, however, is not entirely random but along lines that indicate predominance of one of the three guṇas, thus allowing for beings to be classified into distinct personalities. The Sanskrit aesthetician Bhoja bases his classification of literary characters into four personality types on the Samkhya theory of guṇas. Each personality type shares a number of traits with other personality types but is also characterised by traits unique to it. According to Bhoja, figuring out a literary character's personality type from the knowledge of traits that make it up is the key to understanding his/her mental states. Bhoja's model for literary character analysis not only brings within its scope personality type, traits, self-identity, life-goals and mental states but also explicates their interconnections. Beyond literature, this model has implications for understanding the mental states of real-world individuals, self-introspection and personal growth.