But the Enlightenment discerned the old powers in the Platonic and Aristotelian heritage of metaphysics and suppressed the universal categories’ claims to truth as superstition. In the authority of universal concepts the Enlightenment detected a fear of the demons through whose effigies human beings had tried to influence nature in magic rituals. From now on matter was finally to be controlled without the illusion of immanent powers or hidden properties. For enlightenment, anything which does not conform to the standard of calculability and utility must be viewed with suspicion. Once the movement is able to develop unhampered by external oppression, there is no holding it back. Its own ideas of human rights then fare no better than the older universals. Any intellectual resistance it encounters merely increases its strength. The reason is that enlightenment also recognizes itself in the old myths. No matter which myths are invoked against it, by being used as arguments they are made to acknowledge the very principle of corrosive rationality of which enlightenment stands accused. Enlightenment is totalitarian. [3-4]
Reason, like science, grows by way of mutual criticism; the only possible way of ‘planning’ its growth is to develop those institutions that safeguard the freedom of this criticism, that is to say, the freedom of thought. 
If Popper is right about science then his is also the only genuinely scientific political philosophy; and also, most importantly, the hostility to science and the revolt against reason, both of which are so prominently expressed in today’s world, are directed at false conceptions of science and reason. 
Plato’s principle of leadership is far removed from a pure personalism since it involves the working of institutions; and indeed it may be said that a pure personalism is impossible. But it must be said that a pure institutionalism is impossible also. Not only does the construction of institutions involve important personal decisions, but the functioning of even the best institutions (such as democratic checks and balances) will always depend, to a considerable degree, on the persons involved. Institutions are like fortresses. They must be well designed and manned.
This distinction between the personal and the institutional element in a social situation is a point which is often missed by the critics of democracy. Most of them are dissatisfied with democratic institutions because they find that these do not necessarily prevent a state or a policy from falling short of some moral standards or of some political demands which may be urgent as well as admirable. But these critics misdirect their attacks; they do not understand what democratic institutions may be expected to do, and what the alternative to democratic institutions would be. Democracy (using this label in the sense suggested above) provides the institutional framework for the reform of political institutions. It makes possible the reform of institutions without using violence, and thereby the use of reason in the designing of new institutions and the adjusting of old ones. It cannot provide reason. The question of the intellectual and moral standard of its citizens is to a large degree a personal problem. [ch. 7, 138]
Repudiate bullshit wherever you find it. Reason is worth standing up for.
But be smart about it. Instead of telling people they’re espousing nonsense, ask why they believe what they believe. Then really listen. Be genuinely open to changing your mind. Ask thoughtful questions. Examine the reasoning process that led to their conclusions. Keep your cool. Probe. Then hone in and expose instances of unreason.
What we want to do is create a culture where we take responsibility for what we say, what we think, and what we do. Education isn’t just about you, it’s about the environment around you.
The whole of the above discussion assumes the universality of reason. The reach of science has inherent limitations; so does mathematics; so does every branch of philosophy. But if you believe that there are bounds on the domain in which reason is the proper arbiter of ideas, then you believe in unreason or the supernatural.