48 Algorithms
An algorithm is any sort of routine procedure. A cake recipe is an algorithm for making a cake: if you mix together the ingredients, put them in a pan, put the pan in an oven, and wait for some time, at the end, you will have a cake. Some paper assignments given to students can be done algorithmically: state a thesis, present some arguments, write up a conclusion, and turn it in. The virtue of an algorithm is that it breaks a larger project into a set of smaller steps which, when done in the right order, complete the project. It does not matter who performs the smaller steps so long as they are done correctly. In some cases, the steps are small enough and simple enough for a mindless machine to do them. In that case, when a simple machine can perform an algorithm, we call the algorithm a program. One might think of the laborious “recipe” we follow when we perform long division. That algorithm, or one like it, can be performed by a mindless calculator, thank goodness.
With the advent of computers in the 20th century, more and more of our information has been coded into data that computers can process and manage, which means that more and more of the information at our disposal is processed by algorithms. As I type these words, an algorithm is taking the electrical signals from the keys I press and storing them as numbers; other algorithms are turning those numbers into commands to light up a few pixels on my screen so that I can see what I write. And of course, matters get increasingly complicated from this point forward as I send a file to you through the air and over some wires and your machine receives the signals and you pull up the document and read it. The algorithms in ordinary laptop computers are like complicated factories of routines, all performing their narrow operations so as to produce overall effects that we take for granted—until, that is, something goes wrong and a file won’t load and we curse the machines for being so stupid!
When we turn to the internet to search for the things we are interested in, armies of algorithms take in the information we give them and search for other collections of stored information that “match” what we are looking for (at least according to the programming of the algorithms). The algorithms, of course, do not know what they are doing; they are mindlessly following recipes which (if all goes right) end up with results that satisfy us. Since we cannot count on the algorithms to have any common sense or to know what they are doing, the programmers of the algorithms have to rely on certain tricks that will get the algorithms to do what we want. Search algorithms will look for the websites that most people have ended up going to when they typed words similar to what we typed; they will rank websites according to how popular they are by some measure or other; they may even take a peek at your own history to try to gauge which sites are more likely to satisfy your interests. It is far from foo