Argument: In capitalism, profit is made through exploitation
There are many ways that exploitation is used bring profit in capitalism. The first is through the exploitation of the workers by the capitalist class. This was first described in Capital by Karl Marx and has yet to be disproved. Infoshop (an anarchist information website) describes this process (the extraction of surplus value from workers) quite succinctly: "Under capitalism, workers not only create sufficient value (i.e. produced commodities) to maintain existing capital and their own existence, they also produce a surplus. This surplus expresses itself as a surplus of goods and services, i.e. an excess of commodities compared to the number a workers' wages could buy back. The wealth of the capitalists, in other words, is due to them "accumulating the product of the labour of others."" (Quote is from Kropotkin.) "The measure of surplus-value is the difference between the value-added by and the value paid to the worker. As owner of the means of production, the industrial capitalist has a legal right to keep the surplus-value for himself." A second way is through the subjugation of people and societies on the peripheries in order to extract wealth from them (see the extended argument on imperialism in the history section). An excellent overview of exploitation in capitalism and its causes can be found here and more detail can be found in Historical Capitalism with Capitalist Civilization by Immanuel Wallerstein. Profits in capitalism are always made through exploitation (be it the exploitation of workers for their surplus value, of third world countries for cheap natural resources and cheap markets for goods, etc.) and the institutions of capitalism were designed this way. See the beginning Life Inc by Douglas Rushkoff for a brief explanation of how, why, and by whom the institutions of capitalism were designed. In short, they were designed by the ruling class in the late Middle Ages to keep power over the rising independence of the peasants (and a rising peasant merchant class) by extracting the wealth from the communities and bringing them into the centres of power in the form of profits.