Adam Smith (1723-1790) became one of the founding fathers of economics in his book, An Inquiry into the Nature and Causes of the Wealth of Nations, by introducing the concept of free trade and division of labor. One of his key ideas was the idea of taxation and the role it plays in creating a sustainable system of governance.
The argument Smith makes in regards to taxation is multifaceted, but primarily focuses on two aspects, namely, the advantage of creating a system of taxation that is not oppressive to the people, and understanding the contribution of taxation to broad economic development.
Smith begins his book by stating, “It is the highest impertinence and presumption, therefore, in kings and ministers, to pretend to watch over the economy of private people, and to restrain their expense”, providing the conceptual framework from which he will proceed. He follows this up by laying out the need for a centralized government in order to foster economic growth, which then requires a taxation system to maintain it.
Smith attempts to explain why taxes should be raised in order to develop the economy - taxation provides an infusion of revenue into the national exchequer; this revenue can be used for further development in infrastructure and public works. He was an advocate of progressive taxation, claiming that wealthier citizens (or those with higher incomes) should have to pay more of their income in tax than those who are struggling financially.
Smith was also keenly aware of the dangers of oppressive taxation. As he writes, No tax can be justly imposed...which either exceeds the necessity of the state, or taxes the people beyond their ability to pay; for if it be beyond their ability to pay, it must necessarily impede their industry... He believed that governments needed to provide services and infrastructure to its citizens; this cost had to be paid for, and could be done so through a fair, progressive taxation system.
In summary, Adam Smith argued for the importance of taxation and governmental spending to provide necessary public goods and infrastructure, while keeping taxes fair and affordable for those on low incomes. He believed that a tax system should be progressive, with the wealthier portion of society paying an appropriate amount that allows for the improvement of public works. Smith also held that crippling taxes imposed by governments could lead to economic stagnation and decline, as it would lead to increased poverty and prevent people from engaging in productive activities.