Much if not all we know about the complex mechanism responsible for the development (and stagnation) of productive forces, and for the rise and decay of social organizations, is the result of the analytical work undertaken by Marx and by those whom he inspired.
So long as it is not possible to produce so much that there is enough for all, with more left over for expanding the and extending the forces of production – so long as this is not possible, there must always be a ruling class directing the use of society’s productive forces, and a poor, oppressed class. How these classes are constituted depends on the stage of development.
Engineers were the only members of the community "who understand the needs of the nation, desires of the workmen, and the power of the productive forces"
On the other hand one must not entertain any fantastic illusions on the productive power of the credit system, so far as it supplies or sets in motion money-capital.
The greatest improvement in the productive powers of labour, and the greatest part of skill, dexterity, and judgment with which it is any where directed, or applied, seem to have been the effects of the division of labour.
The annual produce of the land and labour of any nation can be increased in its value by no other means, but by increasing either the number of its productive labourers, or the productive powers of those labourers who had before been employed.