By far the greatest part of those goods which are the objects of desire, are procured by labour; and they may be multiplied, not in one country alone, but in many, almost without any assignable limit, if we are disposed to bestow the labour necessary to obtain them.

David Ricardo

The exchangeable value of all commodities, rises as the difficulties of their production increase.

David Ricardo

Gold and silver, like other commodities, have an intrinsic value, which is not arbitrary, but is dependent on their scarcity, the quantity of labour bestowed in procuring them, and the value of the capital employed in the mines which produce them.

David Ricardo

If a commodity were in no way useful, - in other words, if it could in no way contribute to our gratification, - it would be destitute of exchangeable value, however scarce it might be, or whatever quantity of labour might be necessary to procure it.

David Ricardo