@Tifinden,
I like what Nietzsche said, "Mankind, as a whole, has no goals", and consequently humanity has no purpose. It is through what Nietzsche called "impure thinking" that we assign values to things, by overlooking mankind in general.
Nietzsche suggested that by focusing on limited parts of mankind, such as the pursuit of the "less egotistical type" for example, then we can say that man has a "goal" or "purpose". However, when you take human existence as a whole, then you find that really, at bottom, mankind, and human existence, is aimless.
Its only through "impurity of thought", through overlooking the ultimate aimless of existence, that we can develop a purpose for our own existence; and that is the burden of human existence, to create a purpose for oneself, "in spite of" (Tillich) the apparent aimlessness of existence.