Leshya, a unique concept in Jain metaphysics denoting light or radiation, links the dynamics of the soul (consciousness) and the karmic body with the psycho-physical activities performed by the physical body, and is believed to be associated with every conscious-being, Jeeva (except Ayoga Kevali and Siddha Jeeva). Jeeva in their mundane existence as worldly living-beings, constitute impure states due to association of souls with matter, which profoundly influence their behavior and evolution.
Living Being = F (Subtle body, Gross Body) = F ((Soul + Karmic-particles), (Physical Body))
Leshya, is postulated to relate to the Bhava-Dhara or the stream of emotions, passions and instincts, originating from the dynamic interactions of Adhyavasay with karma induced Kashaya (basic instincts and passions) and the resulting psycho-physical activities (Yoga) of the living organism. Dravya-leshya, the material form, in the presence of kashaya and yoga induce bhava-leshya reflecting the state of consciousness. Bhava-leshya blends in turn with kashaya and yoga to attract corresponding Karmic particles. Bhava-leshya is modified by the instant change in the state and power of the consciousness, thus allowing scope for effort (pursharth) in modification of behavior and diluting karmic determinism.
Behavior dispositions and the spiritual progress of living systems are characterized by 6 different types of leshyas, denoted by different colors: 1. Krsna (black), 2.Nila (blue), 3. Kapot (gray), 4.Taijas (red), 5.Padam (yellow) and 6.Sukla (white). The path of purification of the soul leads from inauspicious leshyas (black, blue and grey) through auspicious leshyas (red, yellow, white) to a stage without Leshya (Aleshi, where there is no Kashaya and Karmic-influx), thus achieving the pure state of consciousness (Ayoga Kevali). During this dynamic process strong correlations between the color of Leshya and the markers of the spiritual development such as Kashaya Intensity, types of Bhava, Dhyan, Gunsthanas and Karma- dynamics have been described.
Leshya also influences the psychophysical activities of the gross physical body and Leshya-Dhyan (color meditation on psychic-centers) is being practiced to improve emotional control and behavior. Associations of Dravya-leshya with the Aghati Karmas viz. Nama- and Gotra-Karma, the determinants of the structure and environment of the physical body, have been described. Since chromosomes and DNA provide the basic genetic information for the development of the physical body, systematic explorations on the precise relationships of Leshya with the structure and functioning of the physical body using the modern scientific methods should be initiated.
Transformation of Leshya from inauspicious (black, blue and grey) to auspicious (red, yellow and white) ones can be brought about by practices directed towards self-realization and soul purification as recommended in the jain philosophy and way of life. The practice of righteous contemplation and virtuous meditation (Samayik) combined with introspection, repentance and forgiveness (Pratikaman) will encourage development of emotional control, self-restraint, tolerance, equanimity, non-violence and compassion as natural personality traits and could be effective in bringing appropriate modifications in human behavior required to meet the challenges in the present day world.
It is further suggested that comprehensive theoretical and experimental studies on the possible correlations of leshya with (a) the pattern of biophotons (emission of very low intensity of coherent light in the wavelength range of 200-900 nm by living organisms) and (b) aura should be undertaken to advance our understanding of leshya and applications of leshya transmutation for behavior modification.