On Truth exists largely as a footnote to Harry G. Frankfurt’s earlier work, On Bullshit. An excellent example of a concise, clear argument, On Bullshit was a brilliant essay on the subject of bullshitting – of communicating without any regard for truth. Bullshitters, Frankfurt argues, are distinct from liars, because liars at least know what the truth is, even though they choose to contradict it. Bullshitters on the other hand don’t know and don’t care about the truth. They communicate with a specific goal in mind (eg. persuasion, improving their popularity), and will say anything in order to achieve this goal.
The purpose of On Truth is to fill a gap identified in the argument against bullshit – an explanation of the importance of truth, a reason why we should care about it. Frankfurt is not concerned with defining truth and falsity – for his purposes the universal, commonsense definition of truth suffices. For example, we all know the truth concerning such things as our names and addresses, and what it means to lie about these. Frankfurt begins by critiquing the relativism of postmodernists who vehemently deny the existence of any objective truth. Regardless of their claims, our lives depend on truth. Engineers need facts about building materials and measurements in order to build a bridge that will not collapse. Surgeons need to know truths about the human body in order to operate on it.
Most of Frankfurt’s argument is similarly utilitarian – we need truth to plan our day-to-day lives, to set long and short term goals, to better understand ourselves, to maintain social cohesion (which is based on trust). This all makes perfect sense and gives you good reason to want to KNOW the truth and, therefore, to resent being bullshitted and avoid bullshitting others. However, it offers little reason for why you should TELL the truth, because a lie might better serve your purposes, and therefore has more value in utilitarian terms. Frankfurt’s essay might convince bullshitters to respect the truth by finding out what it is, but whether they then decide to use it to be honest or deceptive depends on which of these options provides a means to their ends. Consequently, I found that On Truth only achieves part of its goal – it demonstrates the importance of knowing and using the truth, but falls short of convincing one not to lie.
If, when reading On Bullshit, you assumed that it would be better to know the truth, or if this is simply your general conviction, On Truth will probably be incredibly boring – a case of preaching a dull sermon to commonsense converts. There are no insights about truth that I found noteworthy. Compared with On Bullshit, it’s terribly banal. Despite the fact that I could easily have read this in about two hours, I lost steam halfway and only picked it up again about two weeks later, mostly because failing to finish such a tiny book would be just shameful.