from an online review---negative--of Against the Day

[Mark Kohut]

There's a good story in there, maybe a couple. I loved the stuff about the union battles in mining towns, and the Tatzelwurm was spooky. There was a good cowboy revenge story smooshed in there, and with it the only real plot twist in the book. After a couple hundred pages I even reached peace with the endless math, and Pynchon has repeated this enough times: 

i^2 = j^2 = k^2 = ijk = -1 

that I'll begrudgingly admit yes, it is sort of interesting. That is the most interesting math I've seen for years. It's a peculiar equation, for those of you put off by variables, in that it's completely unsolvable any way you look at it. I googled it -- it's a real equation, and it's history is much as he describes it in the book, and it divided the world of mathematics for twenty years -- those years were 1890 to 1910 -- and here is why, and incidentally this is one of the main points of the book; it's non-commutative. 

Non-commutative. That means it only goes one way. It can only be solved by process. 

That's right, that itty bitty equation breaks one of the most fundamental laws of mathematics. To be precise, it posits a new reality where AB does not equal BA. (ij)k does not equal (ji)k. 

The equation suggests a mathematical representation of a world where variables are changed by the process; where cause follows effect. In other words, a world much more like our own.