The problem with what Mr Horgan is advocating is that his argument is based on his view of the Humanities subjects that he teaches, and the way he teaches them.
His view of science subjects, as fields dominated by facts and accepted doctrine based on those facts is an accurate representation of the way science subjects are taught by many teachers, but it does not match the science teaching I received from the teachers and lecturers throughout my school and university life.
There, I was taught that scientific "facts" are opinions tested and supported by experimentation, and which have not yet been proven incorrect. I was taught to consider the experiences of others, but to keep my eyes open and brain engaged, observe the world around me and to form my own opinions, then conduct my own experiments to determine the validity of those opinions. I was given the freedom to decide on the nature of those experiments - did I want to form experiments with a goal of proving and supporting my opinions (the "bias for confirmation" approach, and one in which Mr Horgan is right - we do have an immense capacity for self-and collective delusion), or did I want to actually test the accuracy of those opinions by trying to disprove them?
In short, my science teachers taught me to see all sides of a question, consider as many variables as I could find, look at things as they are instead of how I would like them to be, and form opinions based on those observations. But also to continuously re-evaluate my opinions in the light of any new information that comes to light.
I cannot comment readily on the teaching of the Humanities subjects, as from the age of 14 I concentrated exclusively on the mathematics and science disciplines, plus the fact that some of my friends were starting to experience a pronounced swelling in the chest area. However, my anecdotal recollection is that a lot of my humanities lessons were dominated by "facts" based on what was written in the Bible, a history book, geological or archaeological "facts", and accepted grammar in foreign languages.
On that basis, I feel a more accurate target for his attention would be the teaching methods in schools across all disciplines, where the individual teachers discourage independent critical thinking in favour of memorizing lists of "facts" designed to (1) prepare students for an exam, and (2) give the teacher an easier lesson plan with less preparation.