The notion of the non-self as the Self is as in the thinking of the body as ‘I am Atman’ etc.
And this ignorance (अविद्य) which is the root cause of all क्लेश is called तमस् or error.
The idea of the identity of the intellect (बुद्धि) and the Self (पुरुष) is egoism (अस्मिता ), which is called मोह or delusion.
The kind of erroneous notion that even a man without the necessary means entertains in the form, ‘May all that can be classed under happiness come to me’, is called राग or attachment.
That itself is महामोह the great delusion.
The kind of erroneous notion that one has in the form, ‘Let no pain whatsoever come to me’, even when the causes of pain exist, is द्वेष, aversion. That is तामिस्र.
The particular erroneous notion ‘May I not be separated from these body, organs etc. although they are impermanent’, which is entertained even when one’s life has come to an end and which is a form of fear of death which is natural and common to all creatures including the learned, the women and the children, is अभिनिवेश tenacious clinging to life. That is अन्ध-तामिस्र.
So in Vishnu Purana it says: This अविद्या has five divisions–तमस्, मोह, महामोह, तामिस्र and अन्ध-तामिस्र that were issued out of the परमात्म Paramaatma.
The क्लेश have four states: Of these the dormant (प्रसुप्त ) state is their existence in the unmanifest form, for origination from a non-entity is not possible.
The attenuated (तनु) state is that in which a क्लेश, even though manifest, does not produce any effect in the absence of accessories.
The overpowered (विच्छिन्न) state is that in which a क्लेश, even though it has become manifest and has produced its effect, becomes overpowered by some other क्लेश more powerful than itself.
The expanded, manifested (उदार) state is that in which a क्लेश that has become manifest becomes productive of its result without hinderance, by virtue of getting associated with the accessories.
Of these four क्लेश beginning with egoism (अस्मिता) which are possesed of this kind of four states and are forms of erroneous notion, अविद्य, ignorance itself, in its general form, is the क्षेत्र, the productive field; for all the four have been shown to be the forms of erroneous notions.
In other words, अविद्य is the field that springs forth all क्लेश.
Therefore it follows that from the very cessation of ignrance, अविद्य, there comes the cessation of the क्लेश. This is the idea.
And those क्लेश remain dormant as in the case of the प्रकृति-लय i.e. those merged in Prakrti.
This is the case of those who through self-identification, become merged in the Unmanifest, in the Cosmic Mind known as महत्, the Cosmic Egoism or in the five subtle elements.
The तनु-क्लेश are those that are attenuated through the thought of their opposites (See Yoga Sutra 2.33-34) as in the case of the yogis.
In modern parlance haven’t we come across the exhotation “Think positive!”?
They (the क्लेश), which in both these states are fine or minute, are to be eliminated by resolving them into causal state (see Yoga Sutra 2.10) through निरोध i.e. suppression of the mind, through निर्बीज (निर्बीज समाधि the seedless, objectless समाधि).
But the effects of those क्लेश, which are the modifications of those क्लेश in the fine state, are gross and are called विच्छिन्न and उदार.
They are called विच्छिन्न (overpowered) because they intermittently appear again in their respective forms.
As for instance, anger, though present, does not appear at the time of attraction. Hence it is then said to be विच्छिन्न.
Similarly Kumara (a person) is attached to one woman; it does not mean he is averse to others, but his attachment is manifest with regard to one and remains latent for expression in future with regard to others. In this sense it is said to be विच्छिन्न.
Those क्लेश that have become manifest with regard to objects in general, they at that time, as manifest in their fullness are called उदार (expanded, manifested.)
Both of these – विच्छिन्न क्लेश and उदार क्लेश – being very gross, are to be eliminated through ध्यान (meditation) on Easwara (See yoga Sutra 2.11), which originate from pure सत्त्व; they do not wait for निरोध of the mind.
Those that are to be eliminated through निरोध are only the subtle ones.
And thus all the क्लेश always exist as प्रसुप्त, as तनु, or as विच्छिन्न in the pain arising from consequence, in the anticipation of loss of happiness, or in the fresh craving arising from संस्कार of happiness.
But उदार state belongs to someone of the क्लेश at sometime. This is the distinction.
And these come to be denoted by the word क्लेश since they produce pain that the nature of phychological discord.
All क्लेश do produce the kind of feeling that the mind is averse to.
Since कर्माशय the sublimal impression of right and wrong actions, called either punya or paapa, verily has for its source a क्लेश, and so long as a क्लेश, which is the root, persists, that कर्माशय has its fruition in the forms of birth, life and experience of pleasure and pain, and that कर्माशय, being the producer of its own result here and hereafter, is to be experienced in this visible life or in the unseen life (see 2.12-13 quoted before), and thus the cycle of क्लेश rotate like a Persian wheel, therefore Sri Krishna says appropriately, in this verse of Bhagavat Geetha ‘Since those enjoyments that result from contact with objects are verily the sources of sorrow and have a beginning and an end…’
They are ‘source of sorrow’ because of consequence etc. and the counteraction fo the gunas.
They ‘have a beginning and an end’ because the behaviour of the gunas is unsteady.
This is the explanation according to Yoga Philosophy.
However, the explanation according to Vedantins like me is: अविद्या means ignorance, which is beginningless positive entity.
अस्मिता means the superimposition of the idea of “I” on Consciousness.
राग (attachment), द्वेष (aversion) and अभिनिवेश (clinging to life) are that particular forms of that अस्मिता.
Thus since all these are rooted in अविद्या, therefore all of them without exception are unreal, they being essentially अविद्या.
Although they are unreal like snake superimposed on a rope, they are sources of sorrow.
And they have a beginning and an end, since like dream etc. they merely coexist with cognition.
Hence ‘a wise one’, whose erroneous perception of the basis ‘does not delight in them’, just as a man who knows the real nature of a mirage does not proceed towards it for getting water.
The idea is: Having realized that there is not the least touch of happiness in the world, one should withdraw all the organs from it.
अविद्या is the most painful defect, which is the cause of the experience of all evils, which is difficult to ward off, and which is opposed to the path of liberation has to be removed with great effort by a seeker of Liberation.