Is It Possible to "Make A Difference?"

[IQ89]

I hear this term/expression all the time: somebody wanting to make a difference in the world in some way, shape, or form.

I find the question closely related to the "Do We Have a Purpose" question. People are generally in agreement (here at 2+2 anyway) that we humans do have a biological purpose, but nothing more. Yet, if you listen to those who are convinced that people have some sort of higher purpose, you'll notice they'll almost always say that their purpose consists of/or includes "making a difference" in the world. So I'm asking you, can people literally make a difference in the world, or is it just a matter of opinion (merely a perception)?

Also, for those who are conviced that people can make a difference, what is the criteria for having made a difference in the world?

List The Criteria

1) Helping one or more people in some way?

If yes, then to what degree, and for what length of time? For example, if I help you with your homework one time, is that enough to have made a difference in the world? How about a surgeon saving lives for 40 years? Are Einstein's accomplishments enough? Thomas Edison's? D. Sklansky? Motzart? Bill Gates? etc..

2) Does making a difference have to consist of something admirable in nature?

For example, did the guy who shot John Lennon make a difference? Did Hitler? There is no question these people have changed history, but is that enough? Time magazine was all set to name Hitler the man/person of the century, but due to harsh criticism from many who mistakenly saw the nomination as an honor, Time went with Einstein instead, I believe.