Chapter 2 focuses on the emergence of the modern concept of the reasonable person in nineteenth-century Britain. It argues that this development resulted from the legal and economic needs of the industrial revolution and was informed by the metaphysics of the Scottish sentimental Enlightenment. The chapter’s point of departure is the case known as Blyth v The Company of Proprietors of the Birmingham Waterworks, one of the first cases to discuss explicitly modern law’s reasonable person. Distinguishing between a rational Enlightenment and a sentimental Enlightenment, the chapter then shows that the underlying rationale of the reasonable person relies heavily on the sentimental Enlightenment, namely on David Hume’s and Adam Smith’s thought on the importance of empathy, judgement making in relation to the feelings of others, the incomplete understanding of morality that can be gained from objective reason, and the importance of a human common sense. The third section explains how the industrial revolution and the sentimental Enlightenment influenced the life of Baron Alderson, the judge who oversaw Mr Blyth’s case against the Birmingham Waterworks.

The Conclusion argues that the reasonable person possesses an essence that can be traced across time and across the different jurisdictions we encountered. This essence concerns the concept’s fundamental acceptance that ours is always just one perspective among many and that the best way to understand and assess what others think, do and feel is to empathise with those others. Since the standard is not always understood or applied in this manner, the Conclusion offers a restatement of the function and rationale of the common law’s most illustrious character; the aim is to contribute to the realisation of the concept’s potential and to make it easier to identify instances of misuse. The section unfolds in three parts, which correspond to the three steps of judgement making through empathetic perspective taking: the intention to take the reasonable person’s perspective; the assumption of the reasonable person’s perspective; and the making of a judgement by reference to the reasonable person’s perspective. Ultimately the Conclusion argues that the concept of the reasonable person has significant potential to facilitate the making of tolerant and humane judgements in a diverse, globalised and dynamic society, provided that one remembers that the reasonable person is always someone else.