Ignorance is like darkness. Falsehood (अज्ञान) is dominant in darkness of ignorance (अज्ञान). Embracing the rule of falsehood which conceals the eternal principle of truth is equivalent to inviting the cycle of life and death. Hence the ancient saints have message to go from darkness to light. Yajna, performed with complete concentration and with the right intention of acquiring true knowledge in the presence of the light which washes away darkness, shall create enormous energy in our brain.