The question is what happens to us when we die? Where do we go? Do we cease to exist?
The way you answer this question should have a dramatic impact on how you live your life.
We as humans, according to a Naturalistic (atheist) worldview, are merely a chance directed by natural selection evolved from a primordial soup on a distant planet in a vast, possibly infinitely regressing and expanding universe. I say possibly here because most scientist still agree with a cosmic singularity of the universe, namely the Big Bang.
The end result of this is you are here on earth existing for maybe 100 years, and then you are going back into nothingness. But that fate doesn't just await you, it awaits the entire planet, which, as is theorized by most scientist, will ultimately end up in a heat death where the planet will simply grow cold and disintegrate spreading our cosmic garbage across the ever expanding universe into infinite space.
What does this sort of view lend to your ultimate significance, value and purpose of life. In truth it lends nothing to any of the afore mentioned aspects of life.
1. In regards to Ultimate Significance, basically what does it matter if you find a cure for cancer, or help to bring peace into the middle east, if your life and ultimately the lives of other generations and the earth itself cease to exist in the future the question is left to be answered, "So What?" Why bother, it all goes to nothingness.
2. In regards to Ultimate Value, what does it matter if you try to life a morally upright and correct life. Who determines your right and wrong, if everything is relative then my goods are just as right as yours are even though you don't agree with my anti-hot dog policy, you have to accept it because its my truth and its right to me. Either way what does that matter, when I will leave this world and cease to exist, why shouldn't I do as I please, steal, cheat, rob, kill. It makes no difference what I do since I will not be held responsible in the next life for anything I do here on earth I merely go the way of Hitler and Ghandi, into nothing.
3. Lastly in regards to Ultimate Purpose, if we are nothing more than "electro-chemicals" as Richard Dawkins puts it then we aren't special at all. We have no purpose or importance, we are just a random chance occurrence and our lives will end the same way they started back to non-existence, where is the purpose in living a life like that?
Bottom line is this, without God and Immortality our lives lack all the significance, value and purpose they need for making this present life worth living and fighting for.
As French Mathematician and Physicist Blaise Pascal puts it in his Wager Argument, "...when the odds that God exists are even, then the prudent man will gamble that God exists. This is a wager that all men must take-the game is in progress and a bet must be laid. There is no opting out: you have already joined the game. Which then will you choose--that God exists or that he does not?"
According to William Lane Craig, "Pascal argues that since the odds are even, reason is not violated in making either choice; so reason cannot determine which bet to make. Therefore, the choice should be made pragmatically in terms of maximizing one's happiness. If one wagers that God exists and he does, one has gained eternal life and infinite happiness. If he does not exist, one has lost nothing. On the other hand, if one wagers that God does not exist and he does, then one has suffered infinite loss. If he does not in fact exist, then one has gained nothing. Hence, the only prudent choice is to believe that God exists."
This point of view on God has become known as a "Properly Basic Belief" on which Alvin Plantinga has based his Reformed Epistemology.
So which will you choose?
I have chosen the first and the "Properly Basic Belief." I have nothing to lose and eternity to gain, which do you have?