I AM LEGEND The Butterfly Effect

Due to the theme of the film I am legend I'm not sure that the messages were really that hidden. One part i did like was the scene in the bank vault with all the money on the floor, money is useless without the people their to pack your groceries or cook your food or drive the bus or play music for you to buy. Whereas people could survive without money. But The common theme running through the film that killed of most of New York and the world, or turned them to light avoiding flesh eating zombies. Was the BUTTERFLY.

The Butterfly symbolizes change, do we need to change something?
Will Smith was one man trying to fix a problem he believed he could do it.
References to changes medical companies need to make as they rush medicines in without checking side effects or educating people.
If humans were almost extinct would we provide free medicine to the help, at what point when society was back on its feet would we start charging again?

Theory

The phrase refers to the idea that a butterfly's wings might create tiny changes in the atmosphere that may ultimately alter the path of a tornado or delay, accelerate or even prevent the occurrence of a tornado in a certain location. The flapping wing represents a small change in the initial condition of the system, which causes a chain of events leading to large-scale alterations of events. Had the butterfly not flapped its wings, the trajectory of the system might have been vastly different. Of course the butterfly cannot literally cause a tornado. The kinetic energy in a tornado is enormously larger than the energy in the turbulence of a butterfly. The kinetic energy of a tornado is ultimately provided by the sun and the butterfly can only influence certain details of weather events in a chaotic manner.

Recurrence, the approximate return of a system towards its initial conditions, together with sensitive dependence on initial conditions are the two main ingredients for chaotic motion. They have the practical consequence of making complex systems, such as the weather, difficult to predict past a certain time range (approximately a week in the case of weather).

In summary small things can make a difference, just decide that you can.