The theme is that we live in a world of information and facts. For example, you can find out in an instant that 15 Americans were killed by terrorists in 2010. What you have to decide for yourself is how that number should affect the things you do every day, whether you should be scared, whether you should lobby your government to spend more money fighting terrorists or feeding starving kids (hunger, as it turns out, kills a lot more than 15 Americans a year). And that's where the issues come in. Life is full of risks and probability, but people who don't understand how fractions or percents work aren't enabled to make rational decisions based on what they hear. There are tradeoffs. There's a cost-benefit. Do you want a higher speed limit or fewer traffic fatalities? Safer environment or cheaper toys for the kids?
The book runs through lots of entertaining examples of problems involving numbers, and the point is that they can be solved! There is a way! I don't think we all need to memorize every method, but it's important to just know that the tools are out there. Do you need to find out how likely you are to eat pizza, given the fact that you're an America? Conditional probability! If you lose $100 every time heads comes up on a coin, but win a billion if tails comes up twenty times in a row, should you play the game? Find the expected value!
When we don't understand numbers or science at all, we end up doing stupid things. We believe in medical quacks instead of doctors, because we don't see clinical trials as important... it's easy for a quack to claim that the person he healed is proof that the cure works! And if the person isn't healed, it's because the guy didn't take enough of his cure! See, who needs numbers when you've got gut instinct? Or we think the world is just so crazy when two of our friends have the same birthday... it must be fate! Well how many people do you have to know for two of them to likely have the same birthday? This math can be done. And is done, in the book, but I won't spoil it for you.
A lot of the book is about education and the importance of good teachers, hence the quote I pulled last week about why I became an engineer. So if you're an educator, you'd probably have a whole different list of takeaways from Innumeracy. He actually argues that we should have math specialists in early education, just like kids get pulled out to go to special art and music classes, and that really made me think... why did we decide that music needs to be taught by a special "music person" but math doesn't? My fear is that it comes down to the equipment... you don't need anything as heavy as a piano to teach math, so we figure it doesn't take anyone special. That's an unfortunate decision. But I'm not a teacher.
I appreciated it as a laundry list of reasons why math is important. It does pain me a great deal when I things said to kids like "Of course you have to learn math, someday you'll have to balance a checkbook"... I think math is an artistic, beautiful thing. Appreciating numbers doesn't make you cold or mechanical or computer-like, it gets you to a higher level of thinking about the world. And it is NOT THAT HARD. We need to get past the idea that there are "math people" and "non-math people", and we need to stop laughing it off when someone says they just hate math.
Great book, important book, published in 1990 but surprisingly (or sadly) the issues in society he talks about seem strangely similar to the ones we face today.