In the same manner, if it is proven that mind and intellect are like the soul, these cannot be sole cause of birth. Those who accept the theory of mind and intellect of parents as sole factor of birth then the four categories of species (yonis-jarayuja (born out of amnion), andaja (born out of egg), swedaja (born out of sweat) and udabhija (born by breaking open the earth)) will not be possible.
विद्यात् स्वाभाविकं षण्णां धातूनां यत् स्वलक्षणम्| संयोगे च वियोगे च तेषां कर्मैव कारणम् ||१२||
The natural theory of birth is that the six dhatus (five basic elements- prithvi, apa, tejas, vayu, akasha and the atman (soul)) possess specific qualities, and that the combination and separation of these basic elements, conditioned by the actions of the atman, determines the qualities of the individual at birth.
अनादेश्चेतनाधातोर्नेष्यते परनिर्मितिः| पर आत्मा स चेद्धेतुरिष्टोऽस्तु परनिर्मितिः ||१३||
[Views regarding Paranirmana (soul as the Creator of the Universe)] Consciousness is without any beginning or end, and being eternal it cannot be created by any other thing. Creation by something else refers to the creation of the body by the absolute atman (the supreme consciousness or the supreme soul), and is an acceptable view for the proponents of the theory of reincarnation.
न परीक्षा न परीक्ष्यं न कर्ता कारणं न च| न देवा नर्षयः सिद्धाः कर्म कर्मफलं न च ||१४||
[Yadrichha or free will (power which is responsible for sudden occurrence of events in universe)] Those who are atheists or nihilists do not believe in the theory of creation. As per this view, there is no existence of soul and no examination is warranted to prove its existence. They do not believe that there is any doer or divine cause for the existence of anything.
For these people, there is no existence of God, sages, siddhas, and therefore, they do not believe in concepts such as karma (action) and karmaphala (results of the action). Thus, nihilism constitutes the worst sin in this world.