Kapila Geetaa is a touching story of how a young, but mature son offers solace to his old, dithering mother (Devahooti) who was hungry for spiritual succor. Kapil Geetaa is found in the third canto of the Bhaagvat Puraan. It teaches not only Saankhya philosophy, but also Ashtaang Yog and Bhakti Yog. It was Kapil Muni who opposed sacrifice of a cow in the Veaidik Yagya (called Gosav).

Bhaagvat is the 18th and the last Puraan composed by Ved Vyaas Jee. It is said that the Lord himself appeared as Kapil Muni and his parents were Kardam Rishi and Devahooti. Devahooti was a princess married to Rishi Kardam Jee. She had nine daughters from Rishi and the Lord answered her prayers by taking birth as her son - Kapil Muni. As per Bhaagvat, this is Vishnu's 5th incarnation. Arundhatee, the celebrated wife of Sage Vashishth was his sister.

What is in Kapil Geetaa
Saankhya Darshan - Baadaraayan in his Brahm Sootra starts criticizing the Saankhya first. (2.2.1).
Shankar provides the reason for this. He says this is Pradhaan Malla Nibarhan Nyaaya, which means that it is good to overcome the chief wrestler first.
This indicates the importance of the system also. This system was propagated by Kapil Jee.
The Saankhya accepts three Pramaan (Proofs) - Pratyaksh, Anumaan and Shabd (direct perception, inference and testimony). Saankhya metaphysics categorize all realities in our experience to two fundamental and eternal substances - Prakriti and Purush (the insentient nature and the Being or the soul.)

Every object possesses three characters - pleasure, pain and indifference.
Saankhya considers that there must be three subtle substances from which these characters are derived.
These are Sattwa, Raja and Tamo Gun. Each of these stands for a distinct aspect of physical reality.
These Gun always exist together and can never be separated from each other. When they are in perfect balance, they constitute the Prakriti.
This Prakriti is the primal matter from which the universe evolves.
The Purush (soul) is a conscious entity.
He is eternal ever pure and detached. There are innumerable of these.

The evolution of the world starts with the effective contact between Purush and the Prakriti. The Karm of the Purush disturb the balance of the three Gun in Prakriti and this sets in motion the evolution process.
As a result of Gun mixing with one another, the cosmic intellect (Buddhi) comes out first.
This is followed by Ahankaar (ego), five Gyaanendriyaan, five Karmendriyaan, five Tanmaatraa, five Mahaa Bhoot and Manas (cosmic mind).
In all, there will be 24 cosmic principles. By their permutations and combinations, the rest of creation takes place, each Purush getting a psycho physical complex, which is called the body.

This body comes as per his Karm. This gives a chance for the Purush to attain liberation.
A-Vivek or ignorance is responsible for the bondage; liberation can come only from right knowledge. This can be got by following the eight steps of Yog where the soul is meditated upon.
Saankhya accepts two kinds of liberation - Jeevan Mukti and Videh Mukti. The first is attainable here while living in this world, and Videh Mukti is attained after the death.