What is Happiness?
UG and Nisarga both state that "Happiness is the interval between two sorrows". What this means is that when one says "I am happy". It implies that in the past or in the recent past, I was unhappy. Without knowing Unhappiness one cannot know happiness.
If one says "I want to be happy", it implies that one is unhappy right now. Since in this dual world everything alternates like the moving spokes of a wheel, the next state logically is going to be Unhappiness.
All this is very simple.
In normal Human life Happiness means getting things and doing things ( experiences), this automatically implies an opposite. The opposite means not getting things / losing things and not getting experiences/ loosing things and this is known as Misery. But how are external events deciding ones mental state? Where did the error creep in? In other words external events are sense experiences and happiness is a feeling experience, How did they get interlinked?
Getting things and doing things is a Sense experience, it is a Pleasurable Sense Experience. Not getting things or loosing things and not getting the wanted experiences or loosing experiences is also a Sense experience, this is a Painful Sense Experience. When a Painful sense experience ends, there is relief, the mind gets overexcited with this relief and translates that as Happiness. Actually and factually happiness from external causes is nothing but over excitement caused by relief from pain.
For instance your neighbour has a smart TV and you are under pressure to purchase one, this desire to own the TV causes stress as the senses cant perceive or see the desired object, this is the painful sense experience. The moment the TV is purchased, the senses can perceive and see the desired object as a fulfilled fact, the stress is gone and then there is great relief and the mind is over excited by this relief which it translates as happiness. It was in this manner that the mind got attached to sense experiences by mistaking relief based over-excitement as the happiness feeling.
We know what is happiness? Now, How is the mind experiencing Happiness or Sorrow?
When a desire or want takes hold of the mind. The mind looses its equilibrium and gets stretched out, causing mental tension and this is felt as suffering. When the want or desire is fulfilled the mind gets back to it's original shape or attains equilibrium, there is great relief and mental excitement. This relief based over-excitement is translated as Happiness.
Real Happiness does not involve the mind getting stretched out and tensed and becoming miserable and after that coming back to equilibrium and experiencing relief and excitement. This in-out movement or the sorrow happiness cycle is absent in Real Happiness. In Real Happiness mind goes back to the center, to its roots and abides there and enjoys perpetual happiness, unmindful of the external changes.
Nisarga sums up his own state as "when there is pleasure, I enjoy it and when there is pain, I enjoy that too." For him the mental experience is not connected to sense experience. The mental experience is permanently attached to the source and it is perpetually enjoying bliss, unmindful of the sense experience which keeps fluctuating between pain and pleasure, though witnessing it.
The other major difference between these two happiness is.
In the real happiness of bliss that is got when the mind is permanently at its source, one is unselfconscious.
In the false happiness of excitement due to relief from stress, which is a result of the mind having come back to equilibrium after being pulled out, one is completely self conscious.
Nisarga says that if one can verbalize the state of mind of a person in Bliss it would be. "Nothing is wrong with me or my life, there are no worries". Robert Adam's puts it this way "All is well, everything is unfolding exactly as it should". But if you verbalize the relief based worldly happiness it would be like, "I got this thing, I am happy" or "I got rid of this thing, I am happy".
In such cases one can predict with certainty that his future mental state when verbalized would be like "Things are going wrong in my life, I'm depressed "or "I am unhappy because this department in my life is not improving ", the word department could mean anything touching one's life like career, money, health, status, parents, child, grandchild, grandparents, friends etc.