Excerpts
From An Inquiry into the Nature and Causes of the Wealth of Nations, Book IV, Chap. 2 by . London: Methuen and Co., Ltd., 1904. Edwin Cannan, ed. First published 1776.

But the annual revenue of every society is always precisely equal to the exchangeable value of the whole annual produce of its industry, or rather is precisely the same thing with that exchangeable value.
As every individual, therefore, endeavours as much as he can both to employ his capital in the support of domestic industry, and so to direct that industry that its produce may be of the greatest value; every individual necessarily labours to render the annual revenue of the society as great as he can.

He generally, indeed, neither intends to promote the public interest, nor knows how much he is promoting it.
By preferring the support of domestic to that of foreign industry, he intends only his own security; and by directing that industry in such a manner as its produce may be of the greatest value, he intends only his own gain, and he is in this, as in many other cases, led by an invisible hand to promote an end which was no part of his intention.
Nor is it always the worse for the society that it was no part of it.
By pursuing his own interest he frequently promotes that of the society more effectually than when he really intends to promote it.

I have never known much good done by those who affected to trade for the public good. It is an affectation, indeed, not very common among merchants, and very few words need be employed in dissuading them from it. [Par. IV.2.9]

社會的年收入，總是等于全部年產(chǎn)物的交換價值，甚至可以說，它們其實是同一個東西。
所以，當商人們都盡力將其資本投在國內(nèi)產(chǎn)業(yè)上，并通過細心管理來使生產(chǎn)物達到最高的交換價值時，社會的年收入自然會隨之增加。

商人們的初衷，的確不是增加公共利益。所以，就連他自己在客觀上增加了公共利益，他也不知道。
他所考慮的，只是自己的安全，所以他寧愿將資本投在國內(nèi)產(chǎn)業(yè)上，也不支持國外產(chǎn)業(yè)。
還是出于自身利益的考慮，他采取了可能使其生產(chǎn)物達到最高交換價值的管理方式。
他在自身利益這只看不見的手的指導之下，為達到一個并非他本意想要達到的目的而努力著。
不過，雖然商人的行為不是出于本意，但也不能因此就說這一行為對社會有害。雖然商人的本意是追求自身利益，
但他在追求自身利益的過程中，卻為社會帶來了更多的利益。

有些人雖說是為公眾幸福才從事商業(yè)的，但我從未聽說他們做了什么好事。
幸好這種裝腔作勢的商人并不多見，所以我們也用不著理會他們。

“An economist is a man who states the obvious in terms of the incomprehensible.”

“An economist is an expert know will know tomorrow why the things
he predicted yesterday didn’t happen today.”