MasterDebater

al·tru·ism
n.
Unselfish concern for the welfare of others; selflessness.
Zoology. Instinctive cooperative behavior that is detrimental to the individual but contributes to the survival of the species.

[French altruisme, probably from Italian altrui, someone else, from Latin alter, other. See al-1 in Indo-European Roots.]

Altruism cannot exist. The reason that it can exist is because there is no such thing as "unselfish concern". Concern is a product of the self. To address a concern is entirely selfish. How could it be otherwise? Let us address the word concern.

con·cern
v. con·cerned, con·cern·ing, con·cerns
v. tr.
To have to do with or relate to: an article that concerns the plight of homeless people.
To be of interest or importance to: This problem concerns all of us.
To engage the attention of; involve: We concerned ourselves with accomplishing the task at hand.
To cause anxiety or uneasiness in: The firm's weak financial posture is starting to concern its stockholders.

As you can clearly see concern is generally something of interest or importance. Since one acts on this interest it is self interest. To act in self interest is to be selfish.

self·ish
adj.
Concerned chiefly or only with oneself: “Selfish men were... trying to make capital for themselves out of the sacred cause of human rights” (Maria Weston Chapman).
Arising from, characterized by, or showing selfishness: a selfish whim.