Chapter-1, Sutra 9

Patanjali Yogasutra 1.9 

(Vikalpa):

शब्दज्ञानानुपाती वस्तुशून्यो विकल्पः ॥ १.९ ॥

Verbal delusion follows from words having no (corresponding) Reality.

This Sutra explains the concept of vikalpa, which is one of the five types of mental modifications (vrittis) that Patanjali describes in his Yoga Sutras. Vikalpa is the imagination or fantasy that is based on words or verbal knowledge, but has no corresponding object or Reality in the external world. For example, when we hear or read the word "unicorn", we may form a mental image of a horse-like creature with a horn, but such a creature does not exist in reality. Similarly, when we use words like "Self", "soul", "God", "heaven", etc., we may have different notions or beliefs about them, but they are not verifiable by direct perception or inference. Vikalpa is a source of confusion and error, and it prevents us from attaining the True Knowledge of Reality, which is the goal of yoga.

According to Patanjali, the way to overcome vikalpa is to practice the four means of right knowledge (pramana), which are: direct perception (pratyaksha), inference (anumana), comparison (upamana), and testimony (agama). These are the valid sources of Knowledge that can help us distinguish between Reality and illusion, and lead us to the state of clear and calm awareness (samadhi). Patanjali also advises us to cultivate detachment (vairagya) and discrimination (viveka), which are the qualities that enable us to renounce the false and cling to the true.

The concept of vikalpa is similar to some of the ideas found in other Vedic texts, especially those that belong to the Advaita Vedanta school of philosophy. 

Yoga Vasistha:

विकल्पो नाम मायायां विकल्पो नाम चात्मनि । विकल्पो नाम चैवायं विकल्पो नाम चान्यथा ॥

Vikalpa is nothing but māyā, vikalpa is nothing but the Self,

vikalpa is nothing but this, vikalpa is nothing but otherwise. 

This verse is from the Yoga Vasistha, a syncretic philosophical text that contains the teachings of Sage Vasistha to prince Rama. The verse expresses the paradoxical nature of vikalpa, which is both the cause and the effect of māyā, the illusory power that projects the appearance of multiplicity on the one Reality, which is the Self. Vikalpa is also the means and the end of the spiritual quest, as it is through vikalpa that we seek and realize the truth.

Mandukya Karika:

विकल्पानां विनाशाय विकल्पैरेव योजयेत् ।

विकल्पैर्विकल्पानां नाशो नाशे तु केवलम् ॥

To destroy the vikalpas, one should employ the vikalpas. By the vikalpas, the vikalpas are destroyed, and in their destruction, there is only the absolute. 

This verse is from the Mandukya Karika, a commentary on the Mandukya Upanishad by Gaudapada, the teacher of Adi Shankara. The verse suggests a method of using the vikalpas as a tool for negating the vikalpas, by applying the principle of neti neti (not this, not this). By rejecting all the vikalpas that arise in the mind, one can eventually reach the state of non-duality (advaita), which is beyond all vikalpas.

Pratyabhijnahridayam:

विकल्पः संशयो ज्ञानं विकल्पो विपरीतकम् ।

विकल्पो निर्विकल्पत्वं विकल्पो विकल्पनात् ॥

Vikalpa is doubt, vikalpa is knowledge, vikalpa is error, vikalpa is non-vikalpa, vikalpa is from vikalpa. 

This verse is from the Pratyabhijnahridayam, a text on the Pratyabhijna school of Kashmir Shaivism, attributed to Ksemaraja, a disciple of Abhinavagupta. The verse shows the various aspects of vikalpa, which can be positive or negative, depending on the context and the level of awareness. Vikalpa can be a source of doubt, knowledge, or error, depending on the validity of the cognition. Vikalpa can also be a means of attaining non-vikalpa, which is the state of pure consciousness, free from all mental modifications. Vikalpa is ultimately derived from vikalpa itself, as it is a manifestation of the creative power of Consciousness.