Of all the fundamental concepts propounded in the Puranas, perhaps the most profound is KARMA. 

KARMA is understood, in common usage, as the experiencing of a fixed sequence of events, by the conscious mind.  

The events are unique for each living creature on this planet. There is no overlap.

The Puranas expound on Karmic events as having been predetermined.

The basis of the predetermination is  the accumulated Papam and Punyam from prior Janma of the individual.

Karmic events start with the birth of the individual and end with the demise of the individual. The material world is also born when Karma begins to unravel.  It ceases to be relevant when the individual "dies". 

This is why the Puranas are emphatic that the thought process must be subdued in order to mitigate the ill effects of Karma.

Karma unravels through the conscious mind.  The Mind, and its sub components, the senses, are the instruments through which these events are enacted. 

The mnd experiences Karma in the form of opposing sensations - desire, fear, insecurity, alternating bouts of pleasure/pain etc.The tools through which Karma influences the mind are essentially based on the invoking of 

Karma induces the activity of the mind.

The activity of the mind originates from these preliminary imbalances and opposites. These are the imbalances that the external world induces in the mind. The mind then learns to diminsih the unpleasant and increase the pleasant experiences by changing its responses and behaviour to the external world. In other words, the mind's responses to the impetus provided by the external world is conditioned by the desire for pleasurable experiences. 

The MIND attempts to maximize the "pleasurable" events and eliminate the "unpleasurable" events. This conditioning signals the birth of the human intelligence, which is essentially the override or control of natural responses by subduing desires. We can control the mind only when the mind cannot control you with desires, ambitions, fears and insecurities. This ability to attempt to distinguish and choose, marks the birth of "human intelligence".   

As the MIND is tossed about by the ocean of events (also known as the MAHA PRALAYAM, (or the GREAT DELUGE) in the Puranas),  it begins to distinguish between "desirable" and "undesirable" phenomenon.The ability to distinguish between desirable and undesirable events is referred to in the Puranas as DUALITY. 

Karma has the capability to keep the mind constantly engaged in alternating between sukham and dukkham.  In such a state, it is very difficult to move it into a tranquil/detatched state that is essential for Moksham.

Forces of conflict, struggle and the alternating dominance of material and spiritual forces rock and shred the thought process into bits and pieces. 

The Puranas provide a way out of the conflict by recommending that the mind  develop dispassion and detachment from the world, which is actually a making of its "own" perception!! 

The MIND is pulled from two opposing directions.  One is the experience of the fixed sequence of Karmic events and the other is its need  to avoid entaglement in materialism.  

Dispassion and detachment represent the effort to be unaffected and unifluenced by the "success" and the "failure" that Karmic forces throw at the mind.

KARMA IS RESPONSIBLE FOR THE BIRTH OF HUMAN INTELLIGENCE THROUGH THE PERCEPTION OF A FIXED SEQUENCE OF EVENTS.  KARMA IS ALSO RESPONSIBLE FOR LAYING THE PATHWAY TO THE EVOLUTION OF THE MIND THROUGH A SYSTEM OF INCENTIVES AND DISINCENTIVES.