How on earth are you ever going to explain in terms of chemistry and physics so important a biological phenomenon as first love?

The line contrasts the explanatory power of reductionist science with the felt complexity of human experience. By invoking “chemistry and physics,” it gestures to the idea that love has biochemical and physical correlates, yet suggests that such accounts miss what is most salient about “first love”: its novelty, intensity, and meaning to the person undergoing it. The rhetorical question implies a gap between objective description and subjective significance—an early formulation of the worry that even complete causal accounts may not capture lived experience. In quotation culture it is often used to humanize Einstein, presenting him as skeptical that scientific language can fully translate emotional phenomena.