Many of the basic terms and concepts of critical thinking are also used in the "Boolean logic" of web search engines and other examples of database management. George Boole (1815-1864) was an English mathematician who devised a binary system of symbols for the analysis of logic. A binary system is one in which all the variables are either true or false, or in which they all have the value of either zero or one. Since computers are also binary systems, Boolean algebra seems a perfect fit. But phrases like "Boolean logic" and "Boolean searches" are really misnomers. There's no such thing, in fact, as "Boolean logic"--Boole did not create a system of logic, but a written system to express logic. And, in general, his system is not even used by the web search engines that are usually described as conducting "Boolean searches."
Yet such is the tyranny of jargon, that we will give in and use "Boolean" as a synonym for "logical"!
"Boolean" expressions, then, that are widely used in search engines include such logical terms as:
Consider this example: You want to search the web for information about the American novelist John Gardner, the author of The Sunlight Dialogues and other novels. Unfortunately, there is another contemporary novelist by the name of John Gardner, who has published many more titles, mostly mysteries and thrillers, and who has chosen to continue the James Bond series after the death of its originator, Ian Fleming. Now imagine various Boolean expressions that might help you limit your search results, and the problems those limitations have.
NOTE: With most search engines, putting several words in quotation marks means they are treated as a unit. Therefore, searching for "John Gardner" returns any page where the words "John Gardner" appear in that order (but not instances such as "Gardner, John" or "John C. Gardner"). Searching for John Gardner, without the quotation marks, will find all pages with the words "John" or "Gardner" ("or" because that's what is assumed unless another limiter is specified), in any order (including "Gardner, John" and "John C. Gardner," but also including "Annie John" and "Gardner McKay" as well as the sentence, "The gardner wants to use the john," unless letter case--capital or lower-case--can be specified).
Your activity for this week is to use Digital's search engine Alta Vista, and devise a "Boolean" string to return to largest number of accurate hits, when searching for John Gardner, the American novelist who wrote The Sunlight Dialogues. On Alta Vista's "Advanced Search" page, you can use "and," "or," and "not," but not "xor"; you can also use "near" (so that searching for "Gardner" might return "Gardener"), though I suspect that will not help you much for this assignment. In general, "and" takes precedence over "or," so to control your "Boolean" associations, you can use parentheses, as in:
(A or B) and not (C or D)
Without any parentheses, the search engine would understand that as A or (B and not C) or D, a very different expression.
When you are ready, hit the button below to link to Alta Vista. You'll want to
start with relatively short, simple strings, and to check out the accuracy of the results you
get (by visiting some of the sites), before creating more complicated strings. After you have
created your best search string for John Gardner, report the exact string you used, and the number
of hits it generated, to me.