I think there are several answers to the question "What makes us happy?" Many would argue that there are really no answers at all, and to pretend otherwise is sheer arrogant folly. Others would say that a relationship with God in whatever incarnation you worship (Jesus, Allah, Krishna, Buddha, etc.) is the source of happiness.

Well I'm not as nihilistic as the former and way too agnostic for the latter, but I will say that the primary source of unhappiness must be the inevitability of death. It is the only absolute truth that cannot be controlled or changed (even taxes can be circumvented). Therefore the primary sources of happiness must come from lifelong accomplishments that cheat death in some way.

To that end, here are some general principles, meant only as food for thought:

1) The scientific explanation. The Theory of Evolution maintains that the driving force of species survival is the reproductive success of your children, meaning that when you are a grandparent you can rest assured that your particular set of genes will proliferate in the next generation. All animals, including humans, select mates based upon deeply ingrained characteristics that maximize reproductive success.

Female deer really like the buck who defeats all rivals in antler-crashing contests because he is the strongest, best fed male around, which signals the strength of his genetic makeup. Mixed with her genes, their offspring should be strong and very likely to survive, meaning that her genes are more likely to survive and produce grandchildren, enhancing the survival of the species. Thus long after that lovestruck doe is gone, a piece of her will live on, helping her species propagate in perpetuity.

I think one could say that human women suffer from a similar attraction to the toughest guy around, explaining Sylvester Stallone's long career. The point is, before humans ever conceived the emotion happiness, there existed a driving force that motivated us to get up every day and kill a mastodon. And I think that force still exists, and is experienced by every grandparent: the feeling of satisfaction that comes from seeing your family tree spread new branches.

2) The metaphysical explanation. Of course, there are lots of unhappy grandparents out there. Humans have developed over the course of the last 20,000 years a deeply complex understanding of the world around us and the nature of the interactions between us. We are a highly social species, and often happiness and unhappiness gets mixed up in the fortunes of our social interactions.

I would argue the happiest people out there are ones who are widely respected and valued. The number of people that revere and value you doesn't have to be large; some are content with just having a single mate or friend who knows their worth. I think the most unhappy people are ones who feel left out, ignored, or lonely. They do not feel their worth is recognized. These people tend to be the most destructive. Interestingly, both Hitler and Stalin grew up with distant, abusive fathers.

So how to achieve respect, and therefore happiness? That question I won't even pretend to answer, as it must be handled on a case-by-case basis. What I will say is that giving others respect greatly heightens the likelihood that you will be respected, and respected in a manner that is far deeper and more powerful than someone who respects you out of fear. You as an individual can only live your life the best way you know how, with a sense of justice and mutual respect, and hope that at least one person loves you for that.

And if just one person is affected by you, if just one person loves you for the good person you are, and is enriched by that discovery, then you have made a difference on this planet. You have subtly changed the dynamics of the whole dimension in which we exist, like the tiny wind made by a passing butterfly. And that little ripple will live on, long after you are dead, because energy, once put into motion, never stops. In a way you have cheated death.

There are many works that address this phenomenon, the most popular of which is probably "A Christmas Carol" by Charles Dickens. Ebenezer Scrooge started positively affecting the lives of the people around him, making them more happy and as a result himself much happier, and that little action saved poor Tim's life. Extrapolate that - Tim, a naturally kind and gentle person, lived to grow up and become a man, met a woman and had children, to whom he treated with the same kindness as the now long-dead Scrooge had treated him, and those children grew up, probably poor but very happy, and started their own families, and on and on and on. And all this because of a big Christmas turkey purchased by an angry old man years before.

So happiness, in my view, is the achievement of a tiny amount of immortality. A deeply moving book whose central theme revolves around this is Fyodor Dostoevsky's The Brothers Karamazov.

I also find it interesting that most modern religion revolves around the immortal soul and its fate after your death. No matter what, humans have a strong desire to believe that they will somehow live on after physical death. The only real debate is whether one takes a more secular view, like mine, or a more religious view. Even so, when you consider Jesus' basic teachings - be good to your neighbor, everything in moderation, love your wife, etc., perhaps the only thing separating me from a devout Christian, Jew, or Catholic is acceptance of dogma. I reject dogma without disrespecting it, and I hold no ill for those who find it an important part of their lives. We all just want to live forever, right?