International Journal of Homoeopathic Sciences

Aphorism 153 of the Organon of Medicine forms the cornerstone of homoeopathic philosophy, emphasizing that the most striking, singular, uncommon, and peculiar symptoms should guide the choice of the remedy. Over time, this aphorism evolved into the modern concept of “keynote symptoms” within the Materia Medica, considered the distinguishing features of each remedy. This study aims to establish a conceptual and clinical correlation between Hahnemann’s Aphorism 153 and the development of keynote symptoms, exploring their shared philosophical foundation and practical implications for individualization in clinical practice. A qualitative analytical approach was adopted, examining primary sources such as Hahnemann’s Organon of Medicine (6th edition) and Chronic Diseases, along with secondary texts by Kent, Boericke, Allen, Clarke, and Boger. Comparative textual mapping was carried out to identify how the peculiar symptom described by Hahnemann manifests as the keynote in classical Materia Medica. The findings suggest that Aphorism 153 represents the epistemological root of keynote theory; both emphasize the need to recognize what is characteristic in the patient rather than what is common to the disease. However, overreliance on keynotes without holistic evaluation of totality may diverge from the true spirit of the Organon. The study concludes that integrating Aphorism 153’s original philosophy with modern Materia Medica enhances precision in remedy selection, strengthens homoeopathic education, and preserves the scientific integrity of clinical practice.