The most cynical (but not necessarily inaccurate) view of debt I've seen is that banks loan out imaginary money they don't really have, which was "collateralized" by capital they did not really have, based upon central bank printing presses which create money out of thin air which they don't really have. But then when debtors have trouble repaying onerous loans, the bankers seize real assets. See this and this.
in the time remaining, to help us understand how the man-made system of capitalism will lead to the extinction of our human species, and so many others.
We’ve lived so long under the spell of hierarchy—from god-kings to feudal lords to party bosses—that only recently have we awakened to see not only that “regular” citizens have the capacity for self-governance, but that without their engagement our huge global crises cannot be addressed. The changes needed for human society simply to survive, let alone thrive, are so profound that the only way we will move toward them is if we ourselves, regular citizens, feel meaningful ownership of solutions through direct engagement. Our problems are too big, interrelated, and pervasive to yield to directives from on high.
—Frances Moore Lappé, excerpt from Time for Progressives to Grow Up