Chitta  and its Vrittis : Patanjali’s yoga is also known as raja yoga.Yoga is defined as the cessation of the modifications of chitta.This cessation is through meditation or concentration which is also called yoga.

Chitta means the three internal organs of Samkhya – buddhi or intellect,ahankara or ego and manas or mind.Chitta is the same as antahkarana.It is mahat or buddhi which includes ahankara and manas.Chitta is the first evolute of prakriti and has the predominance of sattva.It is in itself unconscious.But being finest and nearest to purusa,it has the power to reflect the purusa and therefore appears as if it is conscious.When it gets related to any object,it assumes the form of that object.This form is called vritti or modification,The light of consciousness which comes from the purusa and illuminates this form is called jnana.Purusa is essentially pure and is free from the limitations of prakriti.But it wrongly identifies itself with its reflection in the chitta and appears to be undergoing change and modification;chitta,therefore,is the physical medium for the manifestation of the spirit.Just as in a red –hot iron ball,formless fire appears spherical and cold iron appears hot,similarly on account of its reflection in the chitta purusa appears changing and chitta appears conscious.When the purusa realizes that it is completely isolated and is only a passive spectator,beyond the play of prakriti,it ceases to  identify itself with its reflection in the chitta with the result that the light is withdrawn and the modifications of the chitta fallto the ground.This cessation of the modifications of the chitta through meditation is called yoga.It is the return of the purusa to its original perfection.

The modifications of the chitta are of five kinds:

1.Right cognition (pramana)

2.Wrong cognition (viparyaya)

3.Verbal cognition or imagination(vikalpa)

4.Absence of cognition (nidra) and

5.Memory (smriti)

Right cognition is of three kinds :

1.Perception (pratyaksha) :When the chitta through the sense-organs,comes into contact with the internal mental state

2.Inference (anumana): When the chitta cognizes the generic nature of things, and

3.Verbal testimony (shabda)

Viparyaya is positively wrong knowledge like that of a rope-snake.Vachaspati Mishra and Vijnanabhikshu accept doubt also in this category.

Vikalpa is mere verbal cognition like that of a hare’s horn.

Nidra is called absence of cognition;yet it is a mental modification because after sleep a person says ‘I slept sound and new nothing’ and therefore there must be some mental modification to support this absence of knowledge.In nidra vritti there is predominance of tamas.

Smriti is the recollection of past experience through the impressions left behind.

In fact purusa is the eternally pure and transcendental consciousness.It is the chitta with the reflection of the purusa in it or the purusa as reflected in the chitta,which is the phenomenal ego or jiva,which is subject to birth and death and transmigration and to all painful or pleasurable experiences and which imagines itself as the agent and the enjoyer.There are five kinds of sufferings(klesh) to which it is subject .These are:

1.Ignorance (avidya)

2.Egoism (asmita)

3.Attachment (raga)

4.Aversion (dvesha) and

5.Clinging to life and instinctive fear of death (abhinivesha)

 The bondage of the self is due to its wrong identification with the mental modifications and liberation,therefore,means the end of this wrong identification through proper discrimination between purusha and prakriti and the consequent cessation of the mental modifications.ITis the aim of yoga to bring about this result.

There are five levels of mental life (chittabhumi).The differences in the levels are due to the predominance of the different gunas.

The lowest level is called kshipta or restless,because the mind here is restless due to the excess rajas and is tossed about like ashuttlecock between different sense objects.

The second is called Mudha or torpid.The mind here has the predominance of tamas and tends towards  ignorance,sleep and lethargy

The third is called Vikshipta or distracted.Here sattva predominates,but rajas also asserts itself at times.

The fourth Ekagra or concentrated.The mind here is entirely dominated by sattva and rajas and tamas are subdued.The mind becomes concentrated on the object of meditation.The fifth and the highest level is called Niruddha or restricted.Here the mental modifications are arrested,though their latent impressions remain.The first three levels are not at all conducive to yogic life.Only the two are.

These states of mind (vritti) comprise our inner experience.When they lead us towards samsara into the course of passions and their satisfactions ,they are said to be klishta;when they lead us towards samsara or towards mukti,we have to make use of our states of mind;the states which are bad often alternate with good states and whichever state should tend towards our final goal (liberation) must be regarded as good.