Śraddha - the prime force

A ten-month old child touches a hot iron by mistake, burns his hand and never goes near the iron for maybe the next few years. The same child crawls, gets up to walk, staggers, stumbles and falls backwards. In the process he hurts his head badly. The child wails and screams and brings the roof down. A couple of hours later, the child gets up and once again attempts to walk. Why is it that the child who shuns the iron after getting hurt by it just once, gets up to try and walk again and again inspite of numerous falls? Touching the hot iron and falling and hurting his head were both painful experiences, but the reaction is different
This is because of the inherent inner urge that makes the child feel that he has to walk and it is the most natural thing to do. Nothing will stop him from trying to do so, not painful falls or injuries, nor any other setback.
This is 'śraddha' – the prime motive force to practice and progress in Yoga. There is no equivalent word in English [or in Tamil which is my native tongue] for śraddha.  Interest, motivation, faith, belief, trust, eagerness, conviction, enthusiasm, etc – if all these and similar words are put into a box, mixed up and we come up with one word to represent their collective spirit, that word is  śraddha. It refers to an invisible, natural force from within. When śraddha is present impediments and failures do not dilute our energy, but only add to our conviction that more or an altered effort is required.
Ancient literature has a prime slot for  śraddha. There are many more references to  śraddha to highlight its importance. To recall a few simple yet powerful examples
              Śraddha ra āpah -  śraddha is a hot shower after work which eliminates fatigue and rejuvenates.
The Bhagavad Gita says -
              śraddhamyah ayam puruśah              yah yacchraddhah sa eva sah  (17.3) – man consists of  śraddha. Whatever he is [today] is because of his  śraddha.

Can  śraddha be taught?
Taittriya Upanishad analyses a human being as made of five layers. The third layer is 'manomaya' which is that part of us that learns from the outside world. Śraddha is placed beyond this “learning level” in vignanamaya, the fourth layer, which is the base for our value system. Śraddha is the leader placed at the helm of this layer. This indicates two things. One, that  śraddha is beyond learning and logic. And two, that one may learn many things but whether that learning remains mere knowledge or it becomes a part of oneself to guide one's thoughts and actions is decided by the absence or presence of  śraddha.
Śraddha is not a well thought-out and logical conclusion. It is not calculated using complex mathematical formulae. It is not an output of a scientifically tested and proven model or a result of a collective brain power. It is simply a deep rooted inner feeling of conviction that “this is the path I shall walk”.
The greatest contribution that a teacher can make to his student is not to give him information, training, explanations and examples. His main job is to kindle the  śraddha         that is lying dormant. Once he gives life to this  śraddha, learning goes on like a bushfire on a hot windy day. It spreads and gains strength on its own accord.
What is the student's  śraddha?
              Guruvākyesu śastra arthe ca  -  ĀSTIKYA buddhih śraddha  -  At the start of your study, receive and accept the teaching and the teacher with full belief and trust. [the rest will follow automatically]
Vyasa and Patanjali share the same stream of thought process. In his commentary 'Sānkhya Pravacana' Vyasa has equated śraddha with a mother. Like a mother who protects and caresses her infant, so will  śraddha protect our interest – sometimes kind, sometimes strict, sometimes loving, sometimes harsh but always with a single minded devotion to guide and put us on the right path.