Krishna says, "Know that 𝙥𝙧𝙖𝙠𝙧𝙞𝙩𝙞 (nature) and 𝙥𝙪𝙧𝙪𝙨𝙝 (spirit) are both beginningless. 𝙂𝙪𝙣𝙖𝙨 (qualities) and 𝙫𝙞𝙠𝙖𝙧 (evolution or change) are born of 𝙥𝙧𝙖𝙠𝙧𝙞𝙩𝙞 (13.20). 𝙋𝙧𝙖𝙠𝙧𝙞𝙩𝙞 is responsible for cause and effect; 𝙥𝙪𝙧𝙪𝙨𝙝 is responsible for the experience of 𝙨𝙪𝙠𝙝 (pleasure) and 𝙙𝙪𝙠𝙝 (pain) (13.21). Under the influence of 𝙥𝙧𝙖𝙠𝙧𝙞𝙩𝙞 , the 𝙥𝙪𝙧𝙪𝙨𝙝 keeps experiencing the 𝙜𝙪𝙣𝙖𝙨. Attachment to the 𝙜𝙪𝙣𝙖𝙨 is the cause of birth in various wombs" (13.22).
Evolution is the norm of 𝙥𝙧𝙖𝙠𝙧𝙞𝙩𝙞 where situations of yesterday are different than those of today. While change is the norm, we suffer because of our resistance to change as it involves changing ourselves. Living in the present moment without the burden of the past and expectations from the future is the way to transcend this.
𝙋𝙧𝙖𝙠𝙧𝙞𝙩𝙞 is responsible for 'cause and effect' which is usually referred to as physical laws. The 𝙥𝙪𝙧𝙪𝙨𝙝 experiences them as pleasure and pain. When a stone is thrown up, it comes down and when a seed is sown, sprouting happens and the list goes on. When flowers bloom, it's our interpretation that makes them beautiful. Similarly, a scene of death or destruction would be interpreted as painful. Based on many factors, the interpretations vary from person to person for the same situation. As a result, one goes through pleasures and pain; mood swings and blame games. Krishna earlier described (2.14) such interpretations as transient (𝙖𝙣𝙞𝙩𝙮𝙖) and advised us to learn to tolerate them.
𝙎𝙖𝙩𝙫𝙖 , 𝙏𝙖𝙢𝙤 and 𝙍𝙖𝙟𝙤 𝙜𝙪𝙣𝙖𝙨 are born of 𝙥𝙧𝙖𝙠𝙧𝙞𝙩𝙞 . Under their influence, the 𝙥𝙪𝙧𝙪𝙨𝙝 keeps experiencing these 𝙜𝙪𝙣𝙖𝙨 in various proportions at various times. This experience or illusion makes us believe that we are the doer (𝙠𝙖𝙧𝙩𝙝𝙖) . All the human interactions are the result of the interaction between the 𝙜𝙪𝙣𝙖𝙨 . Krishna has repeatedly advised us to transcend these 𝙜𝙪𝙣𝙖𝙨 to become 𝙜𝙪𝙣𝙖-𝙖𝙩𝙚𝙚𝙩𝙝 (the one who has transcended the 𝙜𝙪𝙣𝙖𝙨 ).