<p>In August of 1932, quantum physicist Niels Bohr (1885–1962) delivered to the Second International Congress on Light Therapy meeting in Copenhagen his most extended treatment to that date concerning his reflections on the relevance of the new quantum mechanics for biological questions. Developing this against the backdrop of the “mechanism–vitalism” debate, he sketched out how he envisioned the relations of the new physics with classical issues of function, purpose, and teleology in biology. His address, republished here in its earliest English version, was also given in the context of his ongoing discussions of the relations of physics and biology with the German theoretical quantum physicist Ernst Pascual Jordan (1902–1980). Jordan’s subsequent interpretation of Bohr’s arguments resulted in considerable controversy and a long-term misunderstanding of Bohr’s main points. This contribution gives a detailed summary of this historical discussion and the controversies that surrounded Bohr’s arguments. It also examines Bohr’s final statements on the relations of physics and biology in the period before his death in November of 1962. A closing discussion considers the relevance of Bohr’s insights for contemporary discussions of biological reductionism and the place of the human knower in the scientific process. This is followed by the transcription of the rare 1932 text.</p>