Many of us grew up used to having some news sources we could implicitly trust, such as well-positioned newspapers and radio or TV news programs. We knew they would only hire responsible journalists rather than risk diluting public trust and losing their brand’s value. However, with the advent of the Internet and social media, we are witnessing what has been termed the “post-truth” phenomenon. The undeniable freedom that horizontal communication has given us automatically brings with it the emergence of filter bubbles and echo chambers, and truth seems to become a group belief.

Contrary to my original expectations, the core topic of the book is not about how current-day media brings about post-truth mindsets. Instead it goes into a much deeper philosophical debate: What is truth? Does truth exist by itself, objectively, or is it a social construct? If activists with different political leanings debate a given subject, is it even possible for them to understand the same points for debate, or do they truly experience parallel realities?

The author wrote this book clearly prompted by the unprecedented events that took place in 2020, as the COVID-19 crisis forced humanity into isolation and online communication. Donald Trump is explicitly and repeatedly presented throughout the book as an example of an actor that took advantage of the distortions caused by post-truth.

The first chapter frames the narrative from the perspective of information flow over the last several decades, on how the emergence of horizontal, uncensored communication free of editorial oversight started empowering the “netizens” and created a temporary information flow utopia. But soon afterwards, “algorithmic gatekeepers” started appearing, creating a set of personalized distortions on reality; users started getting news aligned to what they already showed interest in. This led to an increase in polarization and the growth of narrative-framing-specific communities that served as echo chambers for disjoint views on reality. This led to the growth of conspiracy theories and, necessarily, to the science denial and pseudoscience that reached unimaginable peaks during the COVID-19 crisis. Finally, when readers decide based on completely subjective criteria whether a scientific theory such as global warming is true or propaganda, or question what most traditional news outlets present as facts, we face the phenomenon known as “fake news.” Fake news leads to “post-truth,” a state where it is impossible to distinguish between truth and falsehood, and serves only a rhetorical function, making rational discourse impossible.

Toward the end of the first chapter, the tone of writing quickly turns away from describing developments in the spread of news and facts over the last decades and quickly goes deep into philosophy, into the very thorny subject pursued by said discipline for millennia: How can “truth” be defined? Can different perspectives bring about different truth values for any given idea? Does truth depend on the observer, on their knowledge of facts, on their moral compass or in their honest opinions?

Zoglauer dives into epistemology, following various thinkers’ ideas on what can be understood as truth: constructivism (whether knowledge and truth values can be learnt by an individual building from their personal experience), objectivity (whether experiences, and thus truth, are universal, or whether they are naturally individual), and whether we can proclaim something to be true when it corresponds to reality. For the final chapter, he dives into the role information and knowledge play in assigning and understanding truth value, as well as the value of second-hand knowledge: Do we really “own” knowledge because we can look up facts online (even if we carefully check the sources)? Can I, without any medical training, diagnose a sickness and treatment by honestly and carefully looking up its symptoms in medical databases?

Wrapping up, while I very much enjoyed reading this book, I must confess it is completely different from what I expected. This book digs much more into the abstract than into information flow in modern society, or the impact on early 2020s politics as its editorial description suggests. At 160 pages, the book is not a heavy read, and Zoglauer’s writing style is easy to follow, even across the potentially very deep topics it presents. Its main readership is not necessarily computing practitioners or academics. However, for people trying to better understand epistemology through its expressions in the modern world, it will be a very worthy read.