The defining feature of epistemic vices, according to Quassim Cassam, is that they get in the way of knowledge. They inhibit the transmission of knowledge from one person to another, they prevent someone from acquiring knowledge, or they make it harder to retain and recall knowledge when needed. Importantly, epistemic vices don’t always obstruct knowledge, but they tend to do so systematically.
“There would be no justification for classifying closed-mindedness or arrogance as epistemic vices if they didn’t systematically get in the way of knowledge,” writes Cassam in Vices of the Mind. Cassam lays out his argument for striving against mental vices through a lens of consequentialism. Focusing on the outcomes of ways of thinking, Cassam argues that we should avoid mental vices because they lead to bad outcomes and limit knowledge in most cases.
Cassam notes that epistemic vices can turn out well for an individual in some cases. While not specifically mentioned by Cassam, we can use former President Donald Trump as an example. Cassam writes, “The point of distinguishing between systematically and invariably is to make room for the possibility that epistemic vices can have unexpected effects in particular cases.” Trump used a massive personal fortune, an unabashed bravado, and a suite of mental vices to bully his way into the presidency. His mental vices such as arrogance, closed-mindedness, and prejudice became features of his presidency, not defects. However, while his epistemic vices helped propel him to the presidency, they clearly and systematically created chaos and problems once he was in office. In his arrogance he attempted to bribe the prime minister of Ukraine, leading to an impeachment. His closed-mindedness and wishful thinking contributed to his second impeachment as he spread baseless lies about the election.
For most of us in most situations, these same mental vices will also likely lead to failure and errors rather than success. For most of us, arrogance is likely to prevent us from learning about areas where we could improve ourselves to perform better in upcoming job interviews. Closed-mindedness is likely to prevent us from gaining knowledge about saving money with solar panels or about a new ethnic restaurant that we would really enjoy. Prejudice is also likely to prevent us from learning about new hobbies, pastimes, or opportunities for investment. These vices don’t always necessarily lead to failure and limit important knowledge for us, as Trump demonstrated, but they are more likely to obstruct important knowledge than if we had pushed against them.