Maybe the rules of life are competitive: you can only increase your score at someone else's expense. The score is either 0-1 or 1-0. (Maybe you're both starving but only have enough food to sustain one person.)
Or maybe they're cooperative: you can both achieve a >= score if you combine resources/knowledge/what-have-you. The score is 3-3 for cooperating or 1-1 for playing independently. (Take insurance, for example.)
In reality, the game is a complex mixture of these two extremes.
Maybe the rules of life are competitive: you can only increase your score at someone else's expense. The score is either 0-1 or 1-0. (Maybe you're both starving but only have enough food to sustain one person.)
Or maybe they're cooperative: you can both achieve a >= score if you combine resources/knowledge/what-have-you. The score is 3-3 for cooperating or 1-1 for playing independently. (Take insurance, for example.)
In reality, the game is a complex mixture of these two extremes.