“We sow hatred of others fueled by what we think is true, or what we want to be true, without regard to what is true.”

The Preface introduces the theme of The Importance of Evidence-Based Thinking, as Neil deGrasse Tyson criticizes the impact that the lack of rational thinking has on society and politics. Humans are easily swayed by emotions, a fact that is often exploited. Through his criticism, Tyson identifies the purpose of his book: to advocate the use of evidence-based thinking to guide policies and opinions.

“But if you handpick pre-consensus scientific research to serve cultural, economic, religious, or political objectives, you undermine the foundations of an informed democracy.”

Tyson emphasizes the importance of scientific consensus, and his argument suggests that the presentation of new knowledge as truth, without the scientific rigor to confirm that knowledge as objective truth, can have adverse social effects. His assertions serve to delineate scientific data from the overall field of science—concepts which are often conflated. His linguistic choices, such as “handpick” and “serve,” suggest that some individuals purposely exploit the misunderstanding of science versus scientific data.

“Differences in opinion enrich the diversity of a nation, and ought to be cherished and respected in any free society, provided everyone remains free to disagree with one another and, most importantly, everyone remains opens to rational arguments that could change your mind.”

Tyson respects the value of personal truths because they create social diversity. However, he includes two caveats: that everyone is given equal freedom to hold personal beliefs, and that everyone keeps an open mind and considers the weight of rational arguments. Personal (or political) truth that creates social division rather than social diversity, however, goes beyond the bounds of rational behavior and can harm society.