The argument for debt goes like this: in the future "we" will be wealthier, so why don't we borrow against our future income to make the investments that will ensure that, in fact, in the future we will be wealthier.
"We" can refer to a person, business, or nation.
The careful and strategic use of debt has been used to build great empires. A quote:
http://www.ukpublicspending.co.uk/debt_brief.php
"Chart 2 tells, in stark detail, the story of the British Empire. It was built on the National Debt. Throughout the 18th century the National Debt grew and grew, from nothing at the end of the 17th century to about 60 percent of GDP by the end of the War of Spanish Succession in 1715."
To win World War II, the USA drove up debt to 100% of GDP, a level much higher than what it faces today.
To finance business, an interesting difference has developed between the English speaking nations (I mean those who inherit their legal codes from English Common Law) and those nations of continental Europe. In the English speaking nations, it became common, by the 1800s, to finance growth by offering equity for sale at public auction. The continental nations developed along different lines -- banks played a larger role. In Germany, most firms operate with higher levels of debt that what would seem normal in English speaking nations.
To get an understanding of the importance of debt, and its history, I'd suggest you read Fernand Braudel:
http://www.amazon.com/Wheels-Commerce-Civilization-Capitalis...
As he points out, debt and civilization tend to go hand in hand. Debt was illegal in many European nations during the Dark Ages. Nations in the Mideast and India all had flourishing markets in debt, and flourishing trade, while Europe was sunk in poverty. When Europe revived and began to expand again, it helped itself along with the revival of credit, and credit markets. By the time the 1600s came around, Amsterdam was able to offer the world the full range of modern financial instruments: put and short and forward contracts, options of every kind (save for the exotic derivatives of recent vintage).
There is no civilization without debt, no advanced commerce without debt, no growth without debt. The wheels of commerce are greased with credit.
https://www.amazon.com/Civilization-Capitalism-15th-18th-Cen...
https://www.amazon.com/Wheels-Commerce-Civilization-Capitali...
https://www.amazon.com/Perspective-World-Civilization-Capita...
I strongly recommend these books.
If you're interest is more about the classical Western period, I recommend:
https://www.amazon.com/Ancient-Economy-Sather-Classical-Lect...