A commodity is something that has value and can be exchanged for another commodity. Marx’s theory suggests that a commodity gains it’s value through labour power. For example, water in a lake, which is free and available for all to get, is not a commodity. If the lake dries up and a man goes and digs a spring for himself, this water then becomes a commodity. The labour value added to the water is the manual labour of digging. This water now has a value and can be exchanged for another commodity such as bread. The value of a commodity is the ‘socially necessary labour time needed to produce it’. This is the quantity of labour required by an average skilled worker to complete a task. If this concept wasn’t considered then it could be perceived that a product produced by a lazy unskilled worker would have a higher value (Strickland, 2007). This then leads us onto surplus value.
Marx’s describes the surplus value as ‘unpaid labour time’ (Marx, 1906). This is the capitalist profit and occurs due to exploitation. Surplus value is ‘the value of commodities (measured in labour time) minus the amount of labour time needed to reproduce the means of subsistence for the workers’ (Marx, 1906) .The wage paid to a sufficiently productive labourer does not reflect the value of the commodity they are producing (<http//en.wikipedia.org/wiki/Surplus_value>, March 2012). In Marx’s theory the rate of profit is equal to constant capital
References: Marx, K 1906, in eds.Samual Moore & Edward Avelin, Capital: A Critique of Political Economy, Vol. I. The Process of Capitalist Production, 2nd edn, Charles H. Kerr and Co., Chicago. Strickland, R 2007, Cultural Theory: The Labour Theory of Value, You Tube, viewed 8 March 2012, <http://www.youtube.com/watch?v=mFDVb5x-npk>. Labour theory of value, From Wikipedia, the free encyclopaedia n.d., viewed 8 March 2012, <http//enwikipedia.org/wiki/Labour_theory_of_value>. Surplus Value, From Wikipedia, the free encyclopaedia n.d., viewed 8 March 2012, <http//en.wikipedia.org/wiki/Surplus_value>.