Activism, in a general sense, can be described as involvement in action to bring about change, be it social, political, environmental, or other change. This action is in support of or opposition to one side of a controversial argument.
There are many different forms of activism; a select list follows.
... by Strauss, Feuerbach and Bruno Bauer.
Of his numerous writings, the following may be mentioned:
Philosophical
Kritik der Schleiermacherschen Glaubenslehre ...