The Holy Science

[sjel]

I've recently begun reading this book called The Holy Science by Swami Sri Yukteswar.

I just started reading this book as well. How do you interpret the 'yugas' in relation to the densities? So we are well into Dwapara, does that mean that fourth density ends with Dwapara? Also, why does the cycle revert backwards all the way back to Kali Yuga? This doesn't make sense to me, because Sri Yukteswar says this:

The period of 4800 years during which the sun passes through the remaining 4/20th portion of its orbit on either side of the point nearest the grand centre is called Satya Yuga; Dharma, the mental virtue, is then in its fourth stage and completes its full development; the human intellect can comprehend all, even God the Spirit beyond this visible world.

So why would the evolution of man revert back all the way to Kali Yuga, 100,000 times in total before the "creation is dissolved?" Or is that just a metaphor for the sixth density being choosing to Wander and incarnate in third density to balance past karma? (I feel like this timeline isn't relevant once man enters the next yuga and time becomes less concrete.)