The scarcity definition of economics, which emphasises unlimited wants and limited means with alternative uses, is credited to which economist?

Introduction / Context:
Different economists have defined economics in different ways, reflecting changing focuses over time. Classical economists like Adam Smith concentrated on wealth, while later thinkers such as Alfred Marshall stressed welfare. In the twentieth century, Lionel Robbins gave a famous definition that focused on scarcity and choice. Competitive examinations often ask which economist is associated with this scarcity based definition of economics, so it is important to know the correct attribution.

Given Data / Assumptions:

• The scarcity definition describes economics as a science that studies human behaviour as a relationship between ends and scarce means which have alternative uses.
• The options list several well known economists: Dennis Robertson, Lionel Robbins, Alfred Marshall, Adam Smith, and John Maynard Keynes.
• Each of these economists contributed important ideas, but only one is directly associated with the scarcity definition.
• The question expects recognition of the name linked with this particular wording.

Concept / Approach:
Lionel Robbins, a British economist, formulated the scarcity definition in his book on the nature and significance of economic science. His definition highlights that economic problems arise because human wants are unlimited, resources are scarce, and those resources have alternative uses, forcing societies to make choices. This perspective shifted the focus of economics toward the study of choice under scarcity rather than wealth or welfare alone. Therefore, the appropriate answer is Lionel Robbins, not the other economists listed.

Step-by-Step Solution:
Step 1: Recall the wording of the scarcity definition: economics is the science which studies human behaviour as a relationship between ends and scarce means which have alternative uses.Step 2: Identify the economist associated with this formulation, namely Lionel Robbins.Step 3: Compare with other economists. Adam Smith is known for the wealth oriented definition and his book on the wealth of nations.Step 4: Alfred Marshall is associated with the welfare definition of economics, which emphasises material welfare.Step 5: John Maynard Keynes is famous for macroeconomic theories of employment and income, not for the scarcity definition.Step 6: Dennis Robertson contributed to monetary and macroeconomic theory but is not credited with the scarcity definition.

Verification / Alternative check:
Textbooks on the history of economic thought list three main traditional definitions: Adam Smith wealth definition, Alfred Marshall welfare definition, and Lionel Robbins scarcity definition. They further note that Robbins definition is widely cited because it brings out the universal problem of scarcity and choice. Exam oriented summaries also explicitly match Robbins with the scarcity approach and advise students to remember this association for objective questions.

Why Other Options Are Wrong:
Adam Smith emphasised the study of wealth, production, and exchange, not scarcity as such. Alfred Marshall focused on human welfare derived from material goods. John Maynard Keynes analysed macroeconomic issues like employment and aggregate demand. Dennis Robertson worked in monetary and business cycle theory. None of these economists is known for the specific scarcity based definition that refers to ends and scarce means with alternative uses. Therefore, they are not the correct answers to this question.

Common Pitfalls:
Candidates sometimes confuse the names of economists and their definitions because several are learned together. A common mistake is to attribute the scarcity definition to Adam Smith simply because he is the earliest famous economist, or to Marshall because his welfare approach is often taught immediately before Robbins. To avoid such confusion, it helps to memorise the three names together with keywords: Smith and wealth, Marshall and welfare, Robbins and scarcity.

Final Answer:
The scarcity definition of economics is credited to Lionel Robbins.