The human brain is not designed to think clearly. It is designed to survive. Survival does not require accuracy — it requires speed. And so evolution gave us a thinking system that is fast, energy-efficient, and prone to significant error. Psychologist Daniel Kahneman called this System 1 thinking: the automatic, intuitive, pattern-matching mode that handles most of what we do every day. It is useful for routine decisions. It is unreliable for complex ones. System 1 produces cognitive biases — systematic patterns of deviation from rational thinking that affect nearly every decision we make. Confirmation bias makes us seek out information that confirms what we already believe and dismiss information that challenges it. The availability heuristic makes us judge the probability of events based on how easily examples come to mind rather than actual data. Anchoring makes our estimates overly influenced by the first number we hear. These are not weaknesses of unintelligent people. They are features of the human brain that affect everyone, including the most educated and experienced thinkers. The first step in becoming a better thinker is not learning more — it is recognising that your default thinking process is imperfect, that your first impressions and intuitions are frequently wrong, and that the deliberate application of reasoning is worth the extra effort it requires.