In the history of political thought, the term scientific socialism refers to a theory of socialism based on a materialist analysis of society and history. Who is widely regarded as the founder of this scientific socialism?

Introduction / Context:
Scientific socialism is a term used in political science and history to describe a particular form of socialist theory that is based on a systematic, materialist analysis of economic structures and class relations. This approach contrasts with earlier utopian socialists who relied more on idealistic visions than on detailed study of existing society. Identifying the founder of scientific socialism helps students connect key concepts of Marxism with the thinker who developed them.

Given Data / Assumptions:

• The question focuses on scientific socialism, not just socialism in general.
• Four major thinkers are listed: Karl Marx, Lenin, Rousseau, and Engels.
• We assume familiarity with basic political ideologies and their main authors.
• The task is to identify who is widely regarded as the founder of scientific socialism.

Concept / Approach:
The idea of scientific socialism is most strongly associated with Karl Marx. Marx, together with Friedrich Engels, developed a detailed critique of capitalism and argued that the movement of history is driven by class struggle and changes in the mode of production. Their works, such as The Communist Manifesto and Capital, are considered the foundation of scientific socialism. Lenin later applied Marxist ideas to the Russian context, but he did not originate the core theory. Rousseau was an Enlightenment philosopher who wrote about inequality and democracy but not scientific socialism. Engels was a co developer of Marxist theory, but most textbooks credit Marx as the primary founder.

Step-by-Step Solution:
Step 1: Identify that the subject is scientific socialism, meaning socialism based on systematic, materialist study of society.Step 2: Recall that Karl Marx is the main author associated with this theoretical tradition.Step 3: Recognize that Lenin was a revolutionary leader who applied Marxist ideas, not the original founder of scientific socialism.Step 4: Note that Rousseau lived much earlier and focused on social contracts and political inequality, not on Marxist style socialism.Step 5: Understand that Engels worked closely with Marx but is usually mentioned as a co theorist; the primary credit for founding scientific socialism is given to Karl Marx.

Verification / Alternative check:
Any standard text on political theory or the history of socialism states that scientific socialism, or Marxism, was developed by Karl Marx and Friedrich Engels, with Marx playing the leading role. The term scientific is used because Marx claimed his theory was based on a scientific analysis of economic and historical processes. When exam questions ask specifically for the founder, they almost always expect Karl Marx as the answer. Lenin and others are discussed in later chapters as leaders who implemented or adapted Marxist ideas in practice.

Why Other Options Are Wrong:
Lenin was a Russian revolutionary who led the Bolshevik Revolution and applied Marxist theory in Russia, but he did not originate scientific socialism.
Rousseau was an Enlightenment thinker known for The Social Contract and writings on popular sovereignty and inequality, not for scientific socialism.
Engels was Marx's close collaborator and co author, but most standard questions at this level refer to Karl Marx as the primary founder of scientific socialism.

Common Pitfalls:
Students sometimes choose Lenin because they strongly associate him with communism and socialist revolutions. Others may become confused by seeing both Marx and Engels in the options and not being sure whom to select. The safest strategy is to remember that exam questions at this level generally credit Karl Marx as the founder, while also acknowledging that Engels was an important collaborator. Keeping this main association clear will help you answer similar questions quickly.

Final Answer:
The founder most widely regarded as the originator of scientific socialism is Karl Marx.