Refl ective thought and actively open-minded thinking

The explicit concept of refl ective thought as something to be encouraged is fairly recent in human history. Surely it emerged more than once in different cultures, but in Western culture it seems to have originated with the Greeks, a few hundred years before Christ. In the writings of philosophers, it has been discussed more or less continuously since then. One high point was the infl uential Port Royal Logic of 1662 (Arnauld, 1964).