Free Will, Is it real or myth ?

If one believes in cause and effect then free will can not exist.

When we have multiple choices to make a decision and we are free to choose any one we get the impression that we have free will. But if we analyse the situation a bit more closely, we understand that the process of choosing involves weighing several options according to our previous samskaras, accumulated knowledge, responsibilites, interests etc hence it is not free, but a deliberated decision.

If our deliberation tells us that there is not much preference of one decision over the other, then we may pick any one randomly in such case only we may see it was a free decision, but then what is the advantage of a random decision ?

Are we not the limbs/instruments of god/universal consciousness ?

Some times I think that after all, advaita may be true, there is only one consciousness which includes me,you, animal , plant etc.
It appears to be true to me. How can there be me as a seperate being having will power, creative power etc, because I myself came into existence without my knowledge/intention/willpower so how can I claim that I have capability to will on my own, the things that can be done by this body-brain-complex ( which is not willed by me). So this I/me concept appears to be a wrong one.

Does astrology really work ?

I was planning a new business investment, checked out my astrological prediction, it was not good.
done some searching on its validity. I found  some good claims and some good logic against it. I am not sure now whether it has any iota of truth in it !

Do we know the truth about the world today

I spend most of my contemplative time to understand the truth about this world. Are morals required ? does any part of us exist after the death of this body ? if so, does it carry karma of this birth, why no one has conclusively answered and  proved about rebirth? Hindu system says perform nishkama karma i.e work without attachment and desires. If we do not have any desire to work why would we ever work, if we do not work what would be the shape of the world ? Science though limited in its current scope has atleast made some tangible cocrete advances. Philosophy takes everthing in its fold, several people at several times in history said they know everything and everything can be known , but their advice or their arguments become questionable from time to time. Can we arrive at some conclusion which can be beyond doubt and the same followed by every one and the same can be taught as part of our education system ?