In Enlightenment Now, Pinker consistently defends rationality and argues for quantitative evidence. The only way to ensure we’re making progress is to measure it, he argues, and we can and must measure the most important facets of human flourishing—such as education, safety, health, and wealth. This respect for quantitative data itself reflects Enlightenment’s dedication to reason because data can help form a more objective view of reality—a view that isn’t based on feelings, impressions, biases, or beliefs. Because of media’s significant reliance on opinion and conjecture, Pinker asks, “Seeing how journalistic habits and cognitive biases bring out the worst in each other, how can we soundly appraise the state of the world? The answer is to count” (42-43). He practices what he preaches: Throughout his work, Pinker supports his claims by using quantitative data from census reports, voter surveys, psychological studies, and economics research.

Of course, some intellectuals question quantitative analysis as a way to evaluate societal progress, and Pinker expands this theme by thoroughly repudiating their arguments. He quotes leftist intellectual Naomi Klein as saying that climate change activism shouldn’t rely on quantitative evidence. According to Klein, “‘We’re not going to win this as bean counters […] We’re going to win this because this is an issue of values, human rights, right and wrong’” (139).