[Note: This is one of my long comments at another site that I thought I would post here.]
I think our economic lives profoundly influence how we think about broader issues. The degree to which any individual can disagree with one’s superiors and peers without suffering harm to one’s career varies significantly from field to field. In turn, the degree to which mere human opinion plays a role in an individual’s success within a field determines how conformist to common opinion within a field an individual must be to succeed.
For example, individuals in science or engineering rather routinely challenge both their peers and superiors because they have highly objective, non-human evidence by which to determine if an individual’s ideas are wrong or right. A scientific hypothesis either predicts or it does not. Technological artifacts either work or they do not. Likewise, people who create businesses either succeed or fail to earn profits. Mavericks in such fields can overturn a group consensus by the simple expedient of doing something that succeeds or fails. Regardless of how popular an idea might be within the field, a successful counter-idea can kill it. As a result, great diversity of thought exists in these fields.
However, fields in which no external test exists for the validity or usefulness of the ideas in a field become dominated by the group consensus, and individuals must conform to the beliefs of their peers and superiors in order to succeed. In the arts, journalism and especially in the academic liberal-arts, no external test exists for ideas. The fields deal with untestable information. Ideas persist and their creators receive rewards based solely on their popularity. No non-human information can destroy an idea. The ideas do not have to work in any sense, they must merely appeal to a large number of people within the field.
Further, since those within the field cannot prove the validity of their ideas to people outside the field by objective means, they rely on the presentation of a unified front to convey veracity. This is why academics and journalists all tend to tell the same story. The general public can only assume that truth must be what everyone who purports to understand the problem says it is. Any individual who deviates from the pack consensus places everything in doubt. All members of the field therefore have a vested interest in settling on a story and sticking to it. Mavericks threaten the status and position of everyone and therefore cannot be tolerated.
As a result, little diversity of thought exists within these fields. (Their differences with the ideas outside their fields don’t count, because those difference do not impact an individual’s success.)
I don’t think it mere coincidence that leftists dominate those fields in which objective standards do not exist. Instead, I think leftism reflects the world view of those who live in a world lacking objective standards. Leftists are so savage in attacking those who disagree or, worse, those who once agreed but have abandoned the fold, because in the end they only have their collective consensus to support their claims. Mavericks must be destroyed.