I believe that Measurement is meant to be more or less a math text book for students around the middle-school or high-school grades. I'm not in the inI believe that Measurement is meant to be more or less a math text book for students around the middle-school or high-school grades. I'm not in the intended audience, and I'm not a math teacher. I'm just a professional mathematician, so take my opinions with a grain of salt.

I first encountered Paul Lockhart (as many did) through A Mathematician's Lament, an essay highly critical of the status quo in math education. Lockhart's essay was controversial, but many people loved it. I was one that did.

Maybe this excerpt will give an idea of Lockhart's approach:

So no, I can't tell you how to do it, and I'm not going to hold your hand or give you a bunch of hints or solutions in the back of the book. If you paint a picture from your heart, there is no 'answer painting' on the back of the canvas. If you are working on a problem and you are stuck or in pain, then welcome to the club. We mathematicians don't know how to solve our problems either.

With Measurement, Lockhart demonstrates how much more difficult it is to do something right than to point out the flaws in how others are doing it. That being said, Measurement is a brave and important shot at doing math education right. It is far from being a failure. I really liked Part One: Size and Shape, which deals mostly with geometry. Part Two: Time and Space, which introduces calculus, seemed much weaker.

Lockhart included lots of great hand-drawn diagrams. (I'm assuming they are hand-drawn. Maybe they were just made to look that way.) He also has included lots of exercises. Here is an example of his diagrams and exercises in one:

I didn't actually do a lot of the exercises. They just looked too darn hard.

Like I said, Part One I enjoyed. I had a lot of fun with it. Two things that really sparked my interest were projective space and parabolas. Yes I've seen both of these things many times before, but Lockhart gave me some brand new perspectives on them. In fact, I became inspired (jointly by Lockhart and my good friend Jason Lee) to compile a list of mathematical properties of parabolas. You may hear more from me on that in the future...

Part Two was interesting, but it seemed much more contrived. When calculus was first introduced to me (in high school) I was blown away by it. Maybe calculus has just become too trite to me. Any careful introduction of it seems tedious. I'm afraid I've become a poor judge of how engaging an introduction to calculus will be to fresh minds.

In Part Two I did like Lockhart's discussion of space and dimension:

What about four-dimensional space? Is there such a thing? If we're asking whether four-dimensional space is real we might as well ask about three-dimensional space: Is there such a thing? I suppose it appears that there is. We're walking around (apparently), and things certainly look and feel as though they are part of a three-dimensional universe, but when you come right down to it, three-dimensional space is really an abstract mathematical object--inspired by our perception of reality, to be sure, but imaginary nonetheless. So I don't think we should put four-dimensional space in any special mystical category. Spaces come in all sorts of dimensions, and none are any more real than any other. There are no one-dimensional or two-dimensional spaces in real life, and the only thing that gives the number 3 any special status is that our senses appear to offer us that particular illusion.

I would have eaten that kind of stuff up when I was in middle school or high school. Well, OK. I still will eat it up.

Here is something that I think Lockhart gets wrong. He says:

A mathematical structure is what it is, and anything we discover about it is the truth. In particular, if we choose to model an imaginary curve or motion by a set of equations, we are not making any guesses or losing any information through oversimplification: our objects are already (for aesthetic reasons) as simple as they can be. There is no possibility of conflating reality and imagination if everything is imaginary in the first place.

I say to that: "yes and no." In pure mathematics it is true that we are not modeling real-world phenomena with mathematical structures. We are studying the mathematical structures themselves. However, (and it took me a lot of years in pure mathematics to realize this) we can and do model mathematical structures with other mathematical structures. As Lockhart says, the model may be equivalent to the original structure. On the other hand it may not be! It may be that the original structure is just too complicated for us to make any progress, and we need to model it with a simpler structure. Then learning about the simpler structure can tell us things about the original structure, but there is room for error. See my post on the Eternity Puzzle (and the links that it points to) for more on this. In other words, there is (in pure mathematics) the possibility of conflating imagination with imaginary imagination.

Measurement is thought provoking. I hope that it finds its way into some young people's hands....more

I have seen criticism of this book claiming it's not a good "counting book." In fact it is not a counting book at all, and it never claims to be! It dI have seen criticism of this book claiming it's not a good "counting book." In fact it is not a counting book at all, and it never claims to be! It does claim to be a number identification book, which it isn't at all either! In fact it is a numeral identification book. I hope to write about the distinction on my blog soon.

In any case this is a very good, fast paced book. I recommend memorizing the text and the positions of the cars on each page so that you can race through the book, screaming the story as quickly as you can and pointing to the cars as they are named. Just be careful not to rip the pages!...more

This book must be among the pillars underlying modern thought since it first introduced calculus. The middle part is very dry, as Newton himself admitThis book must be among the pillars underlying modern thought since it first introduced calculus. The middle part is very dry, as Newton himself admits. But it is fun to read Newton's Laws of Motion as he originally wrote them and how he arrived at them. For instance, I remember one of my high school teachers saying somthing about when we state Newton's third law it is pretty short, but Newton was very long winded and technical. Not so! "To every action there is always opposed an equal reaction." More interesting are his experiments to verify the Third Law....more

Spent some good days with this book as an undergraduate physics major. It's unique in that the pages appear to be perforated! As if they are meant toSpent some good days with this book as an undergraduate physics major. It's unique in that the pages appear to be perforated! As if they are meant to be torn out! A cruel commentary by the publisher? Or does this serve some other purpose?...more

I just didn't get it. Maybe I didn't invest myself into it enough. Davis and Kirk say that every mathematician should read this book. Whatever (i.e. II just didn't get it. Maybe I didn't invest myself into it enough. Davis and Kirk say that every mathematician should read this book. Whatever (i.e. I disagree)....more

This book didn't quite fulfill my expectations of it. The cover flap promises much

Although mathematics developed along with civilization to help solveThis book didn't quite fulfill my expectations of it. The cover flap promises much

Although mathematics developed along with civilization to help solve practical problems, many people also found that numbers and shaper were fascinating in themselves and began to play with them for pleasure.

It goes on to say that this book explores this more recreational side of mathematics. The book however gets bogged down in defining numbers, telling where they come from, defining odd and even numbers, defining squares and rectangles, explaining that multiplication is commutative and by that time your half way therough the book and there hasn't been much recreation going on.

A strength of the book is that it encourages children to write simple computer programs to do a bit of recreational number theory. This part, I think, is great. I wish that the author had put more emphasis on this sort of thing: running numerical experiments, making guesses about things, making simple arguments to convince oneself that something is true (proofs, but not rigorous ones) and asking their own questions.

Another fault of the book is that there is technical jargon where it is unnecessary. For instance: "...the odd numbers in their proper order." Why doesn't he just say "the odd numbers in order."?

In the end I really like this book, but it I wish that it delivered better on it's promise: skip all the technical definitions. Show some fun examples of things and encourage kids to do mathematical experiments, ask questions for themselves and think about shapes and numbers and patterns for fun. This is a tall order, but I believe it's doable.