Political Economy (General Definition)

A branch of science concerned with the production of commodities and the accumulation of wealth.
‘Political Economy’ was used prior to the 20th century, (when the term ‘Economics’ supplanted it); for its earliest exponents such as William Petty and Adam Smith, Political Economy was a branch of Ethics. With the growth of positivism in the 19th century, however, Political Economy, like Sociology, came to be seen as a branch of science.
The British pioneers of Political Economy contributed much to the development of Hegel's views in that they showed the relation between human thinking and social relations and how these social relations developed through specific historical stages related to the progress of techniques of production.
After the completion of his earliest investigations, Marx concentrated the majority of his theoretical work on the critique of political economy because Marx saw that the work of the political economists most clearly exhibited the ideological forms which dominated bourgeois society: explaining the science of economics through the perspective of the large and small scale capitalist, not through the perspective of the working class.
Bourgeois ideology reifies human activity into separate branches of science, philosophy and so on, whereas for Marxism, it is essential to understand human life as a whole. Marx explained the relation between political economy and ethics:


“It stems from the very nature of estrangement that each sphere applies to me a different and opposite yardstick - ethics one and political economy another; for each is a specific estrangement of man and focuses attention on a particular field of estranged essential activity, and each stands in an estranged relation to the other. ... the opposition between political economy and ethics is only an apparent opposition and just as much no opposition as it is an opposition. All that happens is that political economy expresses moral laws in its own way”.
The point is that political economy does not describe immutable laws that govern humanity, or rather they only appear so, so long as people continue to participate in the forms of production, distribution and exchange on which they are based.