When we see an enormous number, it's hard to understand just how big it is without putting it into context.
For example, Brown University estimates that the War in Afghanistan cost the US $2.313 trillion. We know that's a staggering sum, but just how big is it?
According to the UN, $300 billion is enough to stop the rise in greenhouse gases and buy us an additional 20 years to combat climate change. So, with the amount spent on the war in Afghanistan, you could hit pause on global warming for two decades and still have $2 trillion left over.
Want to eliminate all federal student loans? That will set you back another $1.6 trillion, leaving you with a cool $400 billion, which you could use to fund the National Endowment for the Arts (NEA) at its proposed level for next year ($201 million) for the next two thousand years.
That's not a typo. If you took all the money that was spent on the Afghanistan War, bought the earth 20 more years to fight climate change, and forgave all federal student debt with it, you'd still have enough money left over to fund the NEA until the year 4022.
So here's the question: If we framed spending policies not in terms of dollar amounts, but in terms of the real and tangible opportunity costs associated with those policies, would we make the same decisions?
Postscript: Here's a fun comparison to end on. Setting aside the development and launch costs, the price tag for NASA's Curiosity rover's primary 98-week mission was $116 million. The 2015 film The Martian cost $108 million to make. This means that making a Hollywood movie that takes place on Mars and actually operating a robot on the planet for a couple years cost about the same.