Question
How can you prove the existence of hereafter, i.e. life after death?
Answer

1. Belief in the hereafter is not based on blind faith?
Many people wonder as to how a person with a scientific and logical temperament, can lend any credence to the belief of life after death. People assume that anyone believing in the hereafter is doing so on the basis of blind belief.
My belief in the hereafter is based on a logical argument.

2. Hereafter a logical belief
There are more than a thousand verses in the Glorious Quran, containing scientific facts (refer my book "Quran and Modern Science-Compatible or Incompatible"). Many facts mentioned in the Quran have been discovered in the last few centuries. But science has not advanced to a level where it can confirm every statement of the Quran.
Suppose 80% of all that is mentioned in the Quran has been proved 100% correct. About the remaining 20%, science makes no categorical statement, since it has not advanced to a level, where it can either prove or disprove these statements. With the limited knowledge that we have, we cannot say for sure whether even a single percentage or a single verse of the Quran from this 20% portion is wrong. Thus when 80% of the Quran is 100% correct and the remaining 20% is not disproved, logic says that even the 20% portion is correct. The existence of the hereafter, which is mentioned in the Qur?an, falls in the 20% ambiguous portion which my logic says is correct.

3. Concept of peace and human values is useless without the concept of hereafter Is robbing a good or an evil act A normal balanced person would say it is evil. How would a person who does not believe in the hereafter convince a powerful and influential criminal that robbing is evil?

Suppose I am the most powerful and influential criminal in the world. At the same time I am an Intelligent and a logical person. I say that robbing is good because it helps me lead a luxurious life. Thus robbing is good for me.

If anybody can put forward a single logical argument as to why it is evil for me, I will stop immediately. People usually put forward the following arguments:

a. The person who is robbed will face difficulties
Some may say that the person who is robbed will face difficulties. I certainly agree that it is bad for the person who is robbed. But it is good for me. If I rob a thousand dollars, I can enjoy a good meal at a 5 star restaurant.
b. Someone may rob you
Some people argue that someday I may be robbed. No one can rob me because I am a very powerful criminal and I have hundreds of bodyguards. I can rob anybody but nobody can rob me. Robbing may be a risky profession for a common man but not for an influential person like me.
c. The police may arrest you
Some may say, if you rob, you can be arrested by the police. The police cannot arrest me because I have the police on my payroll. I have the ministers on my payroll. I agree that if a common man robs, he will be arrested and it will be bad for him, but I am an extraordinarily influential and powerful criminal.
Give me one logical reason why it is bad for me and I will stop robbing.
d. Its easy money
Some may say its easy money and not hard-earned money. I agree completely that it is easy money, and that is one of the main reasons why I rob. If a person has the option of earning money the easy as well as the hard way, any logical person would choose the easy way.
e. It is against humanity

Some may say it is against humanity and that a person should care for other human beings. I counter argue by asking as to who wrote this law called humanity and why should I follow it?
This law may be good for the emotional and sentimental people but I am a logical person and I see no benefit in caring for other human beings.

f. It is a selfish act
Some may say that robbing is being selfish. It is true that robbing is a selfish act; but then why should I not be selfish? It helps me enjoy life.

1. No logical reason for robbing being an evil act
Hence all arguments that attempt to prove that robbing is an evil act are futile. These arguments may satisfy a common man but not a powerful and influential criminal like me. None of the arguments can be defended on the strength of reason and logic. It is no surprise that there are so many criminals in this world.
Similarly raping, cheating etc. can be justified as good for a person like me and there is no logical argument that can convince me that these things are bad.

2. A Muslim can convince a powerful and influential criminal
Now let us switch sides. Suppose you are the most powerful and influential criminal in the world, who has the police and the ministers on his payroll. You have army of thugs to protect you. I am a Muslim who will convince you that robbing, raping, cheating, etc. are evil acts.
Even if I put forth the same arguments to prove that robbing is evil the criminal will respond the same way as he did earlier.
I agree that the criminal is being logical and all his arguments are true only when he is the most powerful and influential criminal.

3. Every human being wants justice
Each and every human being desires justice. Even if he does not want justice for others he wants justice for himself. Some people are intoxicated by power and influence and inflict pain and suffering on others. The same people, however, would surely object if some injustice was done to them. The reason such people become insensitive to the suffering of others is that they worship power and influence. Power and influence, they feel, not only allows them to inflict injustice on others but also prevents others from doing likewise to them.

4. God is Most Powerful and Just
As a Muslim I would convince the criminal about the existence of Almighty God (refer to answer proving the existence of God). This God is more powerful than you and at the same time is also just. The Glorious Quran says:
"Allah is never unjust
In the least degree"
[Al-Quran 4:40]

5. Why does God not punish me?
The criminal, being a logical and scientific person, agrees that God exists, after being presented with scientific facts from the Quran. He may argue as to why God, if He is Powerful and Just, does not punish him.

6. The people who do injustice should be punished
Every person who has suffered injustice, irrespective of financial or social status, almost certainly wants the perpetrator of injustice to be punished. Every normal person would like the robber or the rapist to be taught a lesson. Though a large number of criminals are punished, many even go scot-free. They lead a pleasant, luxurious life, and even enjoy a peaceful existence. If injustice is done to a powerful and influential person, by someone more powerful and more influential than he, even such a person would want that person perpetrators of injustice to be punished.

7. This life is a test for the hereafter
This life is a test for the hereafter. The Glorious Quran says:
"He who created Death
And life that He
May try which of you
Is best in deed;
And He is the Exalted
In Might, Oft-Forgiving"
[Al-Quran 67:2]

8. Final justice on day of judgement
The Glorious Quran says:
"Every soul shall have
A taste of death:
And only on the Day
Of Judgement shall you
Be paid your full recompense.
Only he who is saved
Far from the Fire
And admitted to the Garden
Will have attained
The object (of life):
For the life of this world
Is but goods and chattels
Of deception."
[Al-Quran 3:185]
Final justice will be meted out on the Day of Judgement. After a person dies, he will be resurrected on the Day of Judgement along with the rest of mankind. It is possible that a person receives part of his punishment in this world. The final reward and punishment will only be in the hereafter. God Almighty may not punish a robber or a rapist in this world but he will surely be held accountable on the Day of Judgement and will be punished in the hereafter i.e. life after death.

9. What punishment can the human law give Hitler?
Hitler incinerated six million Jews during his reign of terror. Even if the police had arrested him, what punishment can the human law give Hitler for justice to prevail The most they can do is to send Hitler to the gas chamber. But that will only be punishment for the killing of one Jew. What about the remaining five million, nine hundred and ninety nine thousand, nine hundred and ninety-nine Jews?

10. Allah can burn Hitler more than six million times in hellfire
Allah say in the Glorious Quran:
"Those who reject
Our signs, We shall soon
Cast into the Fire;
As often as their skins
Are roasted through,
We shall change them
For fresh skins,
That they may taste
The penalty: for Allah
Is Exalted in Power, Wise"
[Al-Quran 4:56]
If Allah wishes he can incinerate Hitler six million times in the hereafter in the hellfire.

11. No concept of human values or good and bad without concept of hereafter
It is clear that without convincing a person about the hereafter, i.e. life after death, the concept of human values and the good or evil nature of acts is impossible to prove to any person who is doing injustice especially when he is influential and powerful.