Consider what is being read, why it was written, and whether it makes sense.
Critical thinking, generally defined as thoughtful evaluation, is a crucial editorial skill. Beyond being detail oriented, line or copy editors can and should apply some measure of objective analysis to stay mindful of facts that may be incorrect, statements that should be flagged, or correlations that might confuse the reader. It’s true, of course, that editors rely on the author as the subject matter expert, and sometimes I may be reading along, comfortable within the security of an author’s authority, when I realize I must stop to question or double check what is written. Even the best of authors can make unintentional errors, and sometimes we all rely on memory when memory can easily fail us (work in memory studies has shown that the more often we remember something, the more likely it is that the memory becomes distorted–but I might be remembering that wrong!). And sometimes in an effort to get to a point, a minor detail is overlooked, just as when we read, we can often skip over an error because our brain has automatically corrected it for us. As editors, we look out for and flag these instances or make suggestions so that the author can ultimately resolve them.
A propensity to silently question what I’m told (a skill developed in response to a religious upbringing) helped lead me to a career in editing. An editor can quietly think, question, and, if necessary, make changes that hopefully do justice to the author’s intent. I also make my own mistakes, but let’s not discuss those now (or ever). It is never the role of an editor to try to instruct an author about rules of grammar or historical facts or, please never, to offer the editor’s own opinions. Sometimes an author can interpret queries or editorial suggestions in this way, and I try to be sensitive in how I make changes and ask questions to avoid that response. But it is the editor’s role (whether developmental or line or copy editor) to assist the author in the presentation of accurate and reliable work, and to do so, critical thinking/questioning is, well, critical. A scholar approaches a field of study critically to produce a work intended to further the discipline, and albeit on a smaller or different scale, the editor must apply critical thinking to that same end.
Although one clear definition of critical thinking is difficult to find (to further complicate the issue, as philosophy is apt to do, see https://plato.stanford.edu/entries/critical-thinking/), variations of the definition as a process of thoughtful assessment to form a qualified judgment are applied in specific disciplines and to multiple ends. Developing critical thinking in students is a goal of education, and critical thinking skills are often a “soft skill” requested by employers. Depending on the context or source, one can find lists of further delineated critical thinking skills. Consider how five critical thinking skills found on one website directly apply to editorial work: analysis, communication, creativity, open-mindedness, and problem-solving. Others found include applying standards, discriminating, logical reasoning, and inference. As only one example, when editors must discern what an author is saying or implying when the text is unclear, they utilize a number of these skills (e.g., analysis, inference, logical reasoning, problem-solving, etc.). Editors should feel comfortable adding “critical thinking” to their list of marketable skills.
In the larger world, thinking critically, analyzing what is read and heard and applying logic to form a judgment, might also be our best defense against the constant blurring of the line between information, which is thoughtfully researched and promotes independent thinking, and propaganda, the intent of which is to think for us.