If it is true that...

Due to the extensive use of machinery and division of labor, the work of proletarians has lost all individual character

and

Modern industry has converted the small workshop into the great factory of the industrial capitalist

and

Differences of age and sex have no longer any distinctive social validity for the working class

and

The proletariat is recruited from all classes of the population

Then it must be true that...

With its birth, the proletariat begins its struggle with the bourgeoisie

If it is true that...

As the bourgeoisie develops, so does the proletariat, a class of laborers who live only as long as they find work and who find work only as long as their labor increases capital

and

The proletariat is recruited from all classes of the population

Then it must be true that...

With its birth, the proletariat begins its struggle with the bourgeoisie