These are: First.

That as goods are produced to be exchanged, it is good that they should be exchanged as quickly as possible.
Secondly.

That as every producer is mainly occupied in producing what others want, and not what he wants himself, it is desirable that he should always be able to find, without effort, without delay, and without uncertainty, others who want what he can produce.
In themselves these principles are self-evident.

Everyone will admit it to be expedient that all goods wanting to be sold should be sold as soon as they are ready; that every man who wants to work should find employment as soon as he is ready for it.

Obviously also, as soon as the 'division of labour' is really established, there is a difficulty about both of these principles.