Respect and thanks to Paulkershaw soul. I would like to explain the three topics according to my capacity.
Student Life is Best Life:-Life means continuous, till death. Student means enthusiastic, egoless, positive minded, progressing, carefree but not careless, continuous learner. He is detached.
These qualities can never be possible from lowkik point of view. In lowkik, a student does study for some years and then get job. He does not study while eating, drinking. But the aim of RajaYoga is to study all the time(continuous effort).
It is said, as one learns, his ego should reduce. It is correct only in a spiritual student. In lowkik study ego builds up as his status increases.[Of course, even in spiritual student life, if there is lack of purity, such things may be seen. That is why knowledge sits only in pure intellect!].
Knowledge brings happiness:- In lowkik study, knowledge does not give happiness directly. One gets knowledge and then gets a degree. He gets happiness after getting salary (or earning money). By the time the student gets degree if the scope for The Knowledge decreases, the student may get unhappiness instead of happiness.
But in Rajayoga, there is happiness just by remembrance of The Knowledge. Hence knowledge directly gives happiness. Hence it is called jeevanmukti(liberation in life) in a second.
Knowledge is Power:- As the material knowledge has increased, fear and stress have increased in the world. Man has become more knowledgeable, but is about to destroy the whole mankind.
But spiritual knowledge gives such an internal power by which the RajaYogi gets power to face any situation in life(if practiced honestly).
Hence I think, spirituality alone can explain the above three topics completely.
Dear Paulkershaw soul, here also I could not change 'The' to 'the' even after trying to edit. You can consider 'The' and 'the' as same. The same thing had happened even in the previous post. Anyhow, it is not an issue to me.