I wonder if you mind answering this question? How do you conduct and deal with the critical learners in your class?

i will deal with him using the technical parameters keeping in mind this psycological level of the learners 

By understanding them, provide them a chance for their points and introduce advanced technique such as using power point to illustrate pictures and video that can bring their interest to the subject.

to evolve, rather than try at all costs to go "against". ... It is to make others understand what is the basis for making this proposal, how to organize their observations, how to write this proposal in a set.

Critical learner easily understand through the example. I will tell you the true incident how to handle critical learner. One day one so called critical learner went to the bank to deposit the cheque, bank employee told him, it will take3 days for clearance. The guy started argument i.e why it takes3 days whether the cheque is from your next door neighbour bank. The employee said, this is the procedure sir, it takes3 days. He said no... you people are lazy. etc.....etc... Then bank employee asked politely, sir tell if you are passing by near the grave yard and unfortunately if you die on same place.. what will be do...... "Will  your body should take to home or directly burried becuase of grave yard is very near. Critical guy stunned... and shocked and realized t hat he was wrong.