HARKing is the practice of presenting post hoc hypotheses in research reports as if they were a priori hypotheses. This practice is problematic because it can lead to misleading conclusions and undermine the integrity of scientific research. The article discusses various forms of HARKing, including pure HARKing, HARKing with straw men, suppressing loser hypotheses, HARKing with post hoc plausibility and necessity of anticipation, and empirical inspiration. It also explores the reasons why scientists might engage in HARKing, such as the desire to publish and the influence of cognitive biases like confirmation bias and hindsight bias. The article argues that while HARKing may be common, its costs often outweigh its benefits, as it can lead to the construction of illusory theories and the failure to disconfirm hypotheses. The article concludes that HARKing should be discouraged, as it undermines the scientific process and the reliability of research findings.HARKing is the practice of presenting post hoc hypotheses in research reports as if they were a priori hypotheses. This practice is problematic because it can lead to misleading conclusions and undermine the integrity of scientific research. The article discusses various forms of HARKing, including pure HARKing, HARKing with straw men, suppressing loser hypotheses, HARKing with post hoc plausibility and necessity of anticipation, and empirical inspiration. It also explores the reasons why scientists might engage in HARKing, such as the desire to publish and the influence of cognitive biases like confirmation bias and hindsight bias. The article argues that while HARKing may be common, its costs often outweigh its benefits, as it can lead to the construction of illusory theories and the failure to disconfirm hypotheses. The article concludes that HARKing should be discouraged, as it undermines the scientific process and the reliability of research findings.