Of course, I do see the need for "altruistic" behavior depending on circumstance.
But then let's look at what "altruism" is.
Let's assume that the meaning of the "common good" is the behavior of the host organisms that tends to maximize the potential for the survival and future transmission of the DNA within those organisms.
In that case, altruism of say, a parent who dies saving his/her child is justified in a biological sense, and easy to comprehend.
It's harder to figure out the biological motive for something like the Battle of the Somme, where lives were lost in the tens of thousands per hour, but similar forces were at work. Nature seeks an equilibrium, the ultimate force at work is DNA preservation through the sacricifice of the hosts to some ultimate end. The meme for the battle was not for immediate survival, but for a grander goal of defense of a State, which presumably existed for the common good. A group survival mechanism, the death of a few for the life of the whole. But the battle was not for immediate survival, it was for an abstract concept.
So the group sentiment is very strong to preserve the order of society through "selflessness" in the recovery of a stolen camera, regardless of personal risk. The laudable goal of this adventure is now linked to the "preservation of the moral order of society", which can be extrapolated to be linked to the ideal that a well-ordered social structure of law is advantageous to the group aggregate, which is also the basis of "morality". Order creates higher potential for DNA survival. Sending the "bad man" to jail preserves order. It's pre-wired into us all. It's written in the Ten Commandments as the word of "God".
We can then reduce my shameful immorality to a simple cost/benefit judgement. I'm looking for a bargain.
I want to preserve the social order, but how much do I want to pay?
Do I sell myself cheap? Do I risk my DNA and my ability to pass it on to my heirs for for a low or high price?
Is a camera the right price for such risk? Or perhaps the abstract risk of enlisting to fight an "enemy" or to fight "terror" to preserve the structure of my home society?
Do I risk personal danger to return a ten million dollar item or a two hundred dollar camera? To kill an enemy for the common good?
Here's a question I ask myself, how much risk do I want every day to buy survival into the future?
I live 4 blocks from the site of the World Trade Center. On 9/11, hearing a terrible commotion, I turned on the radio and heard that a plane had hit one Tower. I assumed it was a Piper Cub. I took a Nikon Coolpix 990 and a Nikon F100 with tele zoom, and walked outside to pandemonium.
In my mind, I was capturing images of a historical event, living history that I felt obligated to document, even though I knew it was probably being shot by 5000 others. I stayed as close as I could and kept taking pictures, even when I realized that people were jumping out. I saw people falling in the viewfinder and stopped shooting, feeling too ghoulish, then started shooting again thinking "I should take pictures of this for posterity".
I barely escaped with my life, luckily for me, I realized the rumbling noise I heard was the beginning of the building collapse and started to run away.
My bargain was images at the risk of personal life. Creation of the images was a "benefit" in my mind. The risk was disaster, oblivion.
Would I want such to repeat such an adventure? In hindsight, no. The hijackers in the planes thought they were making a grand bargain, the best possible. They also made a judgement. They saw themselves as noble men who were as justified as any of you who would apprehend a thief or even shoot one.
Each day, you buy and sell.