The purpose of this paper is to defend reasonableness from scepticism and to ground its defence on a realistic approach. The main thesis advanced in this analysis is that reasonableness as a legal concept relies on ordinary common sense. After the introduction, in the second paragraph some legal cases are analysed to demonstrate the close links existing between reasonableness and ordinary common sense. In the third paragraph, the Author outlines the main functions of the notion in legal reasoning and their independence from its variable meanings. In the fourth paragraph, the pragmatic features of reasonableness are illustrated to clarify its context-dependence nature. Finally, in the fifth paragraph, the main virtues of the notion and some ...