Marshall’s definition was welfare centred and thus has following criticism.

• Classification of resources on the basis of physical and non-physical nature : Marshall limited the study of subject-matter of economics to the acquisition and consumption of physical resources. But in reality, there are non material resources also like; doctors, engineers, labour, advocates etc, who acquire resources by the of their services and study of these services is done under economics.
• Economics is not social science only : Assuming economics as only social science shall be inappropriate because the rules of economics are such that they apply to people within and outside the society equally. Hence, economics is a human science.
• Relating economics to physical welfare is inappropriate : According to Robbins, economics may be related to anything but it is certain that it is not related to the causes of public welfare. 

Robbins believed the welfare related approach to be faulty on certain grounds.

1. Many activities like production of psychotropic substances and their use is not in the best interest of human welfare, but that is studied as a part of economics. 

2. There is no evidential parameter for welfare. Currency cannot be treated as an evidential parameter for welfare because welfare is a psychological and emotional expression.

• Economics is a Positive Science : When economics is related to welfare, it means that the economists have to decide on pros and cons of economic activities, which relates to normative science. Robbins treats economics as positive science, which does not decide about what is wrong, but rather it studies according to the situation. 
• Scope of economics is skewed : In economics, negligence of the acquisition and consumption of non-physical sources, study of anti social, uncommon and non-economic activities have become the reason for its criticism.