"It is under the commodity-form, that it appears as the means of making money. Money-commodity-more money,—that is the general formula of capital as it appears in the realm of circulation."
Below is from Marx's The Transformation of Money in to Capital. An example of
how consciousness, how ideas in the last analysis have a material base.
This is also true for class consciousness as the short quote explains.
M-C-M describes the function of the capitalist, their role in the
production of life (in class society) and without production there is no
life. They enter the system with money, purchase a commodity, (human
life activity or labor power) and through their control of the labor
process and indeed, the state and society itself, exit the labor process
with a commodity within which contains value that they paid for and
value that they didn't, that was free to them. They sell the commodity
at its value and the value that is the product of unpaid labor time,
that time worked above the time the worker earned their own wages, is the
source of their profit and accumulated wealth. The worker enters the
process with a commodity (their labor power bought by the capitalist)
the capitalist consumes it in the work process that they own and direct,
and owns the end product. The worker seeks through this process the
ability to purchase use values the capitalist seeks exchange value.
That's why the obsession with selling. The value is locked in the
commodity and has to change its form through sale.
conscious representative of this movement, the possessor of money
becomes a capitalist. His person, or rather his pocket, is the point
from which the money starts and to which it returns. The expansion of
value, which is the objective basis or main-spring of the circulation
M-C-M, becomes his subjective aim, and it is only in so far as the
appropriation of ever more and more wealth in the abstract becomes the
sole motive of his operations, that he functions as a capitalist, that
is, as capital personified and endowed with consciousness and a will.
Use-values must therefore never be looked upon as the real aim of the
capitalist; [neither must the profit on any single transaction. The
restless never-ending process of profit-making alone is what he aims at.
This boundless greed after riches, this passionate chase after
exchange-value is common to the capitalist and the miser; but while the
miser is merely a capitalist gone mad, the capitalist is a rational
miser. The never-ending augmentation of exchange-value, which the miser
strives after, by seeking to save his money from circulation, is
attained by the more acute capitalist, by constantly throwing it afresh
Cap Vol 1 Chapter Four: The General Formula for Capital