Pareto laid the foundation of the modern welfare economics by formulating the concept of social optimum…

Vilfredo Pareto's concept of a social optimum (Pareto optimality) is based on "ordinal utility and is free from interpersonal comparisons of utilities and value judgements." Departing from cardinal utilitarianism, Pareto used ordinal preference rankings to define an allocation as optimal when no reorganization can make someone better off without making at least one other person worse off.