Q.Critically explain the four major definitions of economics given by Adam Smith, Marshall, Robbins and Samuelson.

Economics has been defined in four major ways over two centuries, each correcting a weakness in the one before it. Adam Smith (1776) called it the science of wealth; Marshall (1890) shifted the focus to material welfare; Robbins (1932) made scarcity and choice the defining feature; and Samuelson later added economic growth over time to Robbins' scarcity idea.

Economics has been defined in four major ways over roughly two centuries, and each definition reflects both an advance on the one before it and a fresh set of criticisms.

1. Adam Smith's Wealth Definition (1776): In An Inquiry into the Nature and Causes of the Wealth of Nations, Smith treated economics as the science of wealth — studying how a nation produces, accumulates and distributes wealth. His central concerns were the division of labour, free trade and capital accumulation as sources of a nation's prosperity. Criticism: by making wealth the central object of study, the definition invites the charge of reducing economics to a mere 'science of getting rich' (Ruskin and Carlyle's 'gospel of mammon' criticism), and it undervalues the human, welfare side of economic activity.

2. Alfred Marshall's Welfare Definition (1890): In Principles of Economics, Marshall redefined economics as 'a study of mankind in the ordinary business of life,' concerned with how people earn and use income to promote material welfare. This corrected Smith's over-emphasis on wealth by putting human welfare, not wealth, at the centre. Criticism: Robbins pointed out that by tying economics to 'material welfare,' the definition wrongly excludes activities that are undeniably economic but do not clearly promote welfare — the production of tobacco, the economics of a war effort, or a non-material service like a live performance.

3. Lionel Robbins' Scarcity Definition (1932): Robbins abandoned both wealth and welfare, defining economics as 'the science which studies human behaviour as a relationship between ends and scarce means which have alternative uses.' This makes scarcity and choice — not wealth or welfare — the defining feature of any economic problem, and the definition is universal: it applies to a rich economy or a poor one, to any kind of activity where scarce means must be allocated among competing ends. Criticism: it is highly abstract, offers no positive guidance on growth or development, and — by removing any value judgment — some argue it strips economics of its social purpose.

4. Paul Samuelson's Growth-Oriented Definition (20th century): Samuelson combined Robbins' scarcity idea with a forward-looking concern for growth, defining economics as the study of how societies use scarce resources to produce valuable goods and distribute them among people over time, with attention to improving standards of living. This addressed Robbins' main gap by adding a dynamic element — economic growth — while keeping scarcity and choice as the foundation. It is generally regarded, at this introductory level, as the most rounded of the four definitions.

Overall assessment: the four definitions are best read as a historical progression rather than as competing rivals — from wealth, to welfare, to scarcity and choice, to scarcity, choice and growth — each responding to a genuine weakness in the one before it, and together giving a complete picture of what economics studies.