In order to decide whether re-birth exists or not we need to consider two aspects.
One related to God and the other related to the modern science which says there is no need of such personality Lets first consider aspects related to God.
God has innumerable powers and attributes. This imparts him unique character. There is no one equal to him or superior to him. Therefore he is the only one of his kind.
The important attributes of God are
1. Omnipresence – Present everywhere
2. Omniscient - Knows everything
3. Omnipotent - All powerful
4. Replete with infinite happiness, infinite life, infinite knowledge.
It follows that he cannot make any injustice because no one can deceive him and because he is not in need of anything from anyone or no one can harm him anyway; he treats everyone at par.
Now, there are a few questions.
1. Why are some rich other are poor?
2. Why are some more capable and others less capable?
3. Why do some get good opportunities and not others?
4. Why are some Muslims , some Hindu?
5. Why, Why, Why.....in many areas......
If you do not consider re-birth , all blame would be on God and he would be seen as
1. Partial
2. Unkind
3. Unjust
Which is not true.
And if you consider re-birth, all blame would be on soul.
What you get is outcome your own doings in earlier lives. Your bad condition implies your being unjust to others in earlier lives. Re-birth explains everything with a simple saying 'Reap as you Sow.'
Thus all attributes of God are intact. Now there is question to Islam –
'How are all attributes of God justified given that injustice, atrocities, inequalities, sufferings present in this world?'
Islam has no answer. Hindu has.