The question whether there is a life after death does not fall under the jurisdiction of science as science is concerned only with classification and analysis of sense data. Moreover, man has been busy with scientific enquiries and research, in the modern sense of the term, only for the last few centuries, while he has been familiar with the concept of life after death since times immemorial.
All the prophets of God called their people to worship God and to believe in life after death. They laid so much emphasis on the belief in life after death that even a slight doubt in it meant denying God and made all other beliefs meaningless. The very fact that all the prophets of God have dealt with this metaphysical question of life after death so confidently and so uniformly - the gap between their ages being thousands of years - goes to prove that the source of their knowledge of life after death as proclaimed by them all, was the same, i.e., Divine revelation. We also know that these prophets of God were greatly opposed by their people, mainly on the issue of life after death as their people thought it impossible. But in spite of opposition the prophets won so many sincere followers.
The question arises: what made those followers forsake the established beliefs, traditions and customs of their forefathers notwithstanding the risk of being totally alienated from their own community? The simple answer is: they made use of their faculties of mind and heart and realized the truth. Did they realize the truth through perceptual consciousness? Not so, as perceptual experience of life after death is impossible. Actually God has given man besides perceptual consciousness, rational, aesthetic and moral consciousness too. It is this consciousness that guides man regarding realities that cannot be verified through sensory data. That is why all the prophets of God while calling people to believe in God and life after death, appeal to the aesthetic, moral and rational consciousness of man. For example, when the idolaters of Makkah denied even the possibility of life after death, the Quran exposed the weakness of their stand by advancing very logical and rational arguments in support of it:
"And he makes comparisons for Us, and forgets his own (origin and) Creation: he says, 'Who can give life to (dry) bones and decomposed ones (at that)?' Say, 'He will give them life Who created them for the first time! For He fully knows all! - The same Who produces for you fire out of the green tree, when behold! ye kindle therewith (your own fires)! Is not He Who created the heavens and the earth able to create the like thereof?' - Yea, indeed! for He is the Creator Supreme, of skill and knowledge (infinite)!" (36:78-81)
At another occasion the Quran very clearly says that the disbelievers have no sound basis for their denial of life after death. It is based on pure conjecture:
"And they say: 'What is there but our life in this world? We shall die and we live, and nothing but time can destroy us.' But of that they have no knowledge: they merely conjecture: And when Our Clear Signs are rehearsed to them, their argument is nothing but this: they say, 'Bring (back) our forefathers, if what ye say is true!'" (45:24-25)
Surely God will raise all the dead. But God has His own plan of things. A day will come when the whole universe will be destroyed and then again the dead will be resurrected to stand before God. That day will be the beginning of the life that will never end, and that day every person will be rewarded by God according to his or her good or evil deed. The explanation that the Quran gives about the necessity of life after death is what moral consciousness of man demands. Actually if there is no life after death, the very belief in God becomes irrelevant or even if one believes in God, that would be an unjust and indifferent God: having once created man not concerned with his fate. Surely, God is just; He will punish the tyrants whose crimes are beyond count: having killed hundreds of innocent persons, created great corruptions in the society, enslaved numerous persons to serve their whims etc... Man having a very short span of life in this world, and this physical world too being not eternal, punishments or rewards equal to the evil or noble deeds of persons are not possible here. The Quran very emphatically states that the Day of Judgement must come and God will decide about the fate of each soul according to his or her record of deeds:
"The Unbelievers say, 'Never to us will come the Hour': Say, 'Nay! but most surely, by my Lord, it will come upon you;- by Him Who knows the unseen,- from Whom is not hidden the least little atom in the heavens or on earth: nor is there anything less than that, or greater, but is in the Record Perspicuous: That He may reward those who believe and work deeds of righteousness: for such is Forgiveness and a Sustenance Most Generous.' But those who strive against Our Signs, to frustrate them,- for such will be a Chastisement,- of painful wrath." (34:3-5)
The Day of Resurrection will be the Day when God's attributes of Justice and Mercy will be in full manifestation. God will shower His mercy on those who suffered for His sake in the worldly life, believing that an eternal bliss was awaiting them. But those who abused the bounties of God, caring nothing for the life to come, will be in the most miserable state. Drawing a comparison between them, the Quran says:
"Are (these two) alike?- one to whom We have made a goodly promise, and who is going to reach its (fulfillment), and one to whom We have given the good things of this life, but who, on the Day of Judgment, is to be among those brought up (for punishment)?" (28:61)
The Quran also states that this worldly life is a preparation for the eternal life after death. But those who deny it become slaves of their passions and desires, make fun of virtuous and God-conscious persons. Such persons realize their folly only at the time of their death and wish to be given a further chance in the world but in vain. Their miserable state at the time of death, and the horror of the Day of Judgement, and the eternal bliss guaranteed to the sincere believers are very beautifully mentioned in the following verses of the Holy Quran:
"Until, when death comes to one of them, he says: 'O my Lord! Send me back (to life),- In order that I may work righteousness in the things I neglected.' - 'By no means! It is but a word he says.'- Before them is a Partition till the Day they are raised up. Then when the Trumpet is blown, there will be no more relationships between them that Day, nor will one ask after another! Then those whose balance (of good deeds) is heavy,- they will be successful: But those whose balance is light, will be those who have lost their souls, in Hell will they abide. The Fire will burn their faces, and they will therein grin, with their lips displaced." (23:99-104)
The belief in life after death not only guarantees success in the Hereafter but also makes this world full of peace and happiness by making individuals most responsible and dutiful in their activities. Think of the people of Arabia; gambling, wine, tribal feuds, plundering and murdering were their main traits when they had no belief in life after death. But as soon as they accepted the belief in the One God and life after death they became the most disciplined nation of the world. They gave up their vices, helped each other in hours of need, and settled all their disputes on the basis of justice and equality. Similarly the denial of life after death has its consequences not only in the Hereafter but also in this world. When a nation as a whole denies it, all kinds of evils and corruptions become rampant in that society and ultimately it is destroyed. The Quran mentions the terrible end of Àd, Thamüd and the Pharaoh in some detail:
"The Thamüd and the ہd people disbelieved in the Day of Noise Calamity! But the Thamüd,- they were destroyed by a terrible Storm of thunder and lightning! And the ہd, they were destroyed by a furious Wind, exceedingly violent; He made it rage against them seven nights and eight days in succession: so that thou couldst see the (whole) people lying overthrown in its (path), as if they had been roots of hollow palm- trees tumbled down! Then seest thou any of them left surviving?
And Pharaoh, and those before him, and the Cities Overthrown, committed habitual Sin. And disobeyed (each) the messenger of their Lord; so He punished them with an abundant Penalty. We, when the water (of Noah's Flood) overflowed beyond its limits, carried you (mankind), in the floating (Ark), That We might make it a Reminder unto you, and that ears (that should hear the tale and) retain its memory should bear its (lessons) in remembrance.
Then, when one blast is sounded on the Trumpet, And the earth is moved, and its mountains, and they are crushed at one stroke,- On that Day shall the (Great) Event come to pass. And the sky will be rent asunder, for it will that Day be flimsy, And the angels will be on its sides, and eight will, that Day, bear the Throne of thy Lord above them. That Day shall ye be brought to Judgment: not an act of yours that ye hide will be hidden.
Then he that will be given his Record in his right hand will say: 'Ah here! Read ye my Record! I did really think that my Account would (One Day) reach me!' And he will be in a life of Bliss, In a Garden on high, The Fruits whereof (will hang in bunches) low and near. Eat ye and drink ye, with full satisfaction; because of the (good) that ye sent before you, in the days that are gone!
And he that will be given his Record in his left hand, will say: 'Ah! Would that my Record had not been given to me! And that I had never realized how my account (stood)! Ah! Would that (Death) had made an end of me! Of no profit to me has been my wealth! My power has perished from me!'... (The stern command will say): 'Seize ye him, and bind ye him, And burn ye him in the Blazing Fire. Further, insert him in a chain, whereof the length is seventy cubits! This was he that would not believe in Allah the Most High. And would not encourage the feeding of the indigent! So no friend hath he here this Day. Nor hath he any food except the foul pus from the washing of wounds, Which none do eat but those in sin.'" (69:4-39)
Thus there are very convincing reasons to believe in life after death.
Firstly, all the prophets of God have called their people to believe in it.
Secondly, whenever a human society is built on the basis of this belief, it has been the most ideal and peaceful society, free of social and moral evils.
Thirdly, history bears witness that whenever this belief is rejected collectively by a group of people in spite of the repeated warning of the prophet, the group as a whole has been punished by God even in this world.
Fourthly, moral, aesthetic and rational faculties of man endorse the possibility of life after death.
Fifthly, God's attributes of Justice and Mercy have no meaning if there is no life after death.