This conclusion can be reached without reference to any religion, and I actually did so.

Just to show my background, I will start by telling that I believe in the God of the Bible. I have chosen so, even though Christianity is constantly becoming less popular, and it is portrayed as an old fashioned philosophy and lifestyle based on some old stories from unverified sources. I have been able to take the unpopular choice because I refuse to be manipulated by the masses and the media, and because I feel strongly that I must be intellectually honest to live a happy life. If you are intellectually honest, you might reach different conclusions than me, but you will not be upset by mine.

I would like to share with you how I came to the conclusion that I should live as if there is an afterlife - that I, in some form or another, will continue to exist after my physical body dies. Although I am Christian, I'm not arguing in favor of any particular belief or any particular God, but for the concept of an afterlife in general. Thus it could be of interest to anyone, even atheists.

Short version

If an afterlife is possible, if I have a free will, and if my actions have any effect on my afterlife, I will be infinitely better off by taking it into account whenever possible.

In more detail

The possibility of an afterlife

We have no objective proof for or against an afterlife, but if there is even a small logical possibility of such, the significance of it would infinitely outweigh the relative weight of the current life. If an afterlife was infinite (finite, but with no limit), what would 50 years be in comparison to that? If we can't rule out the possibility of an afterlife, it should be taken into account.

Free will

To the degree I have free will, I am responsible for my actions. To the degree I can affect the outcome of some process, I am responsible for the outcome. If I can choose to eat less, but continue to eat more, I am responsible for getting fatter. If I can choose to go south but decide to go north, I will likely end up north. There are things I can decide, and things that happen regardless of what I choose.

If there was no free will, as it is popular to believe, I don't know how it would change my proposition. I would still have to do what my mind tells me to, which is to keep practising my percieved free will, and take responsible actions.

The effect of actions and decisions on the possible afterlife

If there is a possibility that my choices and actions determine what my possible afterlife will be like, I should take it into account. I should actively search for understanding and experiences that guide me in the right direction. I should not let common opinion affect my search for possible hints and more understanding. If I neglect the possibility of my actions having a causal effect on my afterlife, I will myself be responsible for the outcome if they do. I think this view presupposes a belief in a supernatural being acting as a "judge" or defining the rules, or the laws of the universe functioning in some similar way.

The possible afterlife should be the determining factor in my decisions

This is game theory. I can either 1) take into account the possibility of an afterlife or 2) not take into account the possibility of an afterlife. The outcome will be an a) afterlife or b) no afterlife. The results will be as follows:

• 1a, I take into account the possibility of an afterlife, and there turns out to be an afterlife: I will have played my cards well, and possibly have an good afterlife without any end, or with new "rounds". Infinite win.
• 1b, I take into account the possibility of an afterlife, but there turns out to be none: I will have lived a conscious and consistent life with an assurance of a positive outcome, while giving up some things that are generally considered pleasures. I will never learn that my preparing for the afterlife was in vain. Depending on subjective measures, outcome + or - a few points.
• 2a, I neglect the possibility of an afterlife, and it turns out there actually is an afterlife: I will have chosen short term pleasures while having a distant uncertainty and fear or death. I will have to blame myself for the outcome. Infinite loss.
• 2b, I neglect the possibility of an afterlife, and there turns out to be none: Only the quality of my life will matter. Depending on personal preferences and circumstances, life might have been pleasant or unpleasant. Result is + or - a few points.

From this comparison I concluded that my "dominant strategy" is to bet on an afterlife.

Further thoughts

Possible objections

There is a general conception that religious life is restricted, and that secular life is more enjoyable. Therefore the outcome of 2a and 2b should be better. I disagree. I enjoy my life as a Christian immensely. I have lots of pleasures, and I think that I am able to enjoy the pleasures even more because I am free from fear of death. I am thankful for wine, sex, beauty, speed, fun, leisure, rewarding work and what not.

Some think that science contradicts with religion, including the prospect of an afterlife. Personally I experience no conflict between the two. Actually scientific discoveries can greatly support arguments in favor of religion, including afterlife.

Bonuses

I think taking the possibility of an afterlife into account helps you develop a consistent personal philosophy, and gives you motivation to actually act according to it.

Being sure that you are doing everything you can to maximize your chance of a positive outcome gives you peace of mind regarding death.

You find friendship with others with similar goals.

Hope of an afterlife in itself is a positive thing, and it can greatly help in overcoming hardships.

Conclusion

My thoughts are similar to those of the mathematician Blaise Pascal. Instead of "taking into account the possibility of an afterlife", he used "belief in God". I think my model is more general in regard to different religions, but more specific as an argument. Thus it is more useful and applicable.

Starting to take the possibility of an afterlife into consideration is a smart move. If done right, it will help you live an enjoyable life with coherent decisions. It will surely boost your personal relationships and possibly your career
and financial situation. It will give you more peace of mind, which will boost everything else. In case there turns out to be an afterlife, you will congratulate yourself. In the worst case, you might have missed out on some possible fun.

I am not trying to persuade anyone into religion. I know it doesn't work that way. People decide based on feelings and then find the logical support for their decisions. So actually I don't even know why I wrote this. Maybe you can give me some constructive feedback on my reasoning? In any case it's helpful to write down ones thoughts. In another article I will write about why I choose to take into account the possibility of a God. Thanks for reading!