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When we tell a computer how to do something, we write a set of orders for the computer in a way that the computer can read. These orders can ask the computer to remember things, like numbers and names and places and so on. We can ask the computer to set up spots where it will remember things for us, and each such spot will have its own name. When we write down a thing for the computer to figure out, and the computer goes on to actually figure out what we are talking about, the thing can turn out to be either of two types. It can be the name of a place to store things, or it can be a thing to be stored (like a number or word or letter or a few of any of these). If it is a place to store things (which we can call a "left hand type of thing"), we could ask the computer to store other things in that place. If it is a thing that can be stored (which we can call a "right hand type of thing"), we could ask the computer to store it somewhere. The reason why we use the names "left hand" and "right hand" in this way is that we can write orders for the computer like cat should become two times two In this case, the word "cat" appeared on the left hand side of the order, before "should become" (or "gets"), while the words "two times two" appeared on the right hand side of the order, after "should become". This makes sense because in this order we use "cat" as a name of a place to store things, while "two times two" (which turns out to be the number four) is a number that could be stored so that it can be used later on. Here, we would call "cat" a left hand type of thing, and "two times two" a right hand type of thing. In some orders for the computer, the way to talk about where to store things is much more confusing (like we could say something like "right after this place", "right before this place", "ten spots after this place"), but still, if something works out to point to a place where you can store facts, then that thing is a left hand type of thing. |