"Certainly nothing is unnatural that is not physically impossible"

Richard Brinsley Sheridan’s observation, “Certainly nothing is unnatural that is not physically impossible,” invites a reflection on the boundaries between what is considered natural and unnatural. The conventional view draws a sharp distinction between what belongs within the normal course of nature and what appears to fall outside it, labeling deviations or novelties as unnatural. Sheridan’s statement, however, shifts the parameters for such judgment from familiarity or tradition to the fundamental laws that govern the physical universe.

By suggesting that only the physically impossible qualifies as truly unnatural, he establishes that anything capable of occurring within the possible operations of nature, no matter how rare, unconventional, or contrary to human norms, belongs legitimately to the realm of nature. The conception of “unnatural” thus undergoes significant contraction. Events or phenomena often dismissed as aberrant or contrary to nature’s design, whether in human behavior, technological advancements, or strange occurrences in the physical world, become part of the spectrum of the natural provided they adhere to physical laws.

This perspective renders the boundary between the natural and unnatural less a question of morality, taste, or social convention and more an inquiry into what the universe can accommodate. Human aversion towards certain acts or phenomena often arises from discomfort, misapprehension, or unfamiliarity rather than objective impossibility. Sheridan’s insight challenges us to expand our understanding, grounding our criteria not in subjective or cultural judgements but in the objective framework provided by physical possibility.

Furthermore, by making physical impossibility the sole marker of the unnatural, Sheridan subtly encourages intellectual humility. Our knowledge of possibility is limited, and as understanding deepens, many things believed unnatural or impossible may eventually become integrated into natural explanation. The genuine marvel, then, is not in what feels alien or extraordinary, but in those things which the universe truly cannot support. Everything else, however strange or unsettling, belongs within the tapestry of what nature allows.