The article by Steven E. Hyman discusses the challenges and limitations of diagnosing mental disorders, particularly focusing on the *Diagnostic and Statistical Manual of Mental Disorders* (DSM) and the *International Classification of Diseases* (ICD). Hyman highlights the need for interrater reliability in diagnosis, which was addressed by the DSM-III and DSM-IV through operationalized criteria. However, these criteria were developed when scientific understanding of mental disorders was limited, leading to a reification of disorders as discrete entities rather than heuristic constructs. This reification has impeded scientific progress and created epistemic blinders that hinder the development of valid diagnoses. Hyman argues that the current classification systems, while providing a shared language for clinical practice and research, are based on phenomenology and lack a solid scientific foundation. The DSM-IV and ICD-10 criteria are often treated as natural kinds, leading to their widespread use in research, treatment development, and legal and administrative contexts. This has resulted in significant challenges, such as the difficulty in developing treatments for conditions that do not match the current diagnostic criteria. The article also explores the concept of validity in diagnosis, noting that valid diagnoses should be based on etiology or pathophysiology. However, due to the lack of robust scientific understanding, the current classification systems rely heavily on phenomenological criteria. Hyman suggests that the upcoming revisions to the DSM-V and ICD-11 should aim to improve the validity of diagnoses by moving away from categorical definitions and towards more dimensional or quantitative approaches. The article concludes by discussing the challenges of classification in living systems, using examples from biology to illustrate the difficulties in defining species and disorders. It emphasizes the need for a more nuanced and flexible approach to diagnosing mental disorders, one that is grounded in scientific understanding and avoids the pitfalls of rigid, categorical definitions.The article by Steven E. Hyman discusses the challenges and limitations of diagnosing mental disorders, particularly focusing on the *Diagnostic and Statistical Manual of Mental Disorders* (DSM) and the *International Classification of Diseases* (ICD). Hyman highlights the need for interrater reliability in diagnosis, which was addressed by the DSM-III and DSM-IV through operationalized criteria. However, these criteria were developed when scientific understanding of mental disorders was limited, leading to a reification of disorders as discrete entities rather than heuristic constructs. This reification has impeded scientific progress and created epistemic blinders that hinder the development of valid diagnoses. Hyman argues that the current classification systems, while providing a shared language for clinical practice and research, are based on phenomenology and lack a solid scientific foundation. The DSM-IV and ICD-10 criteria are often treated as natural kinds, leading to their widespread use in research, treatment development, and legal and administrative contexts. This has resulted in significant challenges, such as the difficulty in developing treatments for conditions that do not match the current diagnostic criteria. The article also explores the concept of validity in diagnosis, noting that valid diagnoses should be based on etiology or pathophysiology. However, due to the lack of robust scientific understanding, the current classification systems rely heavily on phenomenological criteria. Hyman suggests that the upcoming revisions to the DSM-V and ICD-11 should aim to improve the validity of diagnoses by moving away from categorical definitions and towards more dimensional or quantitative approaches. The article concludes by discussing the challenges of classification in living systems, using examples from biology to illustrate the difficulties in defining species and disorders. It emphasizes the need for a more nuanced and flexible approach to diagnosing mental disorders, one that is grounded in scientific understanding and avoids the pitfalls of rigid, categorical definitions.