Realism or "anti-psychologism" is a theory that states that the truth does not depend on what the human mind thinks of it or conceives it, but rather exists independently of what the human mind thinks.
The concept of realism help spread revolutionary ideas within Latin America. Figures like Jose "Che" Guevara and Fidel Castro came from this movement. In regards to Europe, independentist movements who shared this philosophy appeared throughout Spain (ETA) and Eastern European countries.