What does a dictionary definition do?
Too many people seem to think that the purpose of a dictionary is to create a authoritative log of words and their meanings. These people think that the dictionary is an exhaustive of words used in whatever language they are cataloging. Each entry is a supposed unalterable absolute. The thought is that what is written in the dictionary is what a word means, has always meant, and will always mean. This is not what dictionaries do.
When you look at print dictionary (the things that I used to look words up in when I was a kid), you are struck with the smallness of it. Even the giant dictionaries that you used to find in the public library that looked like giant tomes of ancient prayers and incantations were noticeably finite. And when you looked at the entries for individual words, you would find the entries to be no more that 3 or 4 lines on a multicolumn page. We all know that words have a multitude of meanings and there is no way that these few lines on these few pages could not possibly hold every use for every word. Online dictionaries have constraints on them as well although their constraints come more from the time and dedication of the dictionary’s writers than from the space allotted in the pages of a book. Therefore, it is not possible that a dictionary could hold all possible uses of every word, nor do they even try.
A dictionary is a tool that helps speakers of a language understand that language as it is being spoken at the time of the writing of the dictionary. So what a dictionary does is report how a word is being used at the time of the writing of the dictionary. And even then dictionaries cannot include all of the different uses and connotations of each word, so the dictionary writers record the most common uses of the word. The writers know that their definitions are not exhaustive, and they assume that their readers know this too. Dictionary writers assume (often incorrectly) that dictionary readers will use their definitions as a starting point to help suss out additional meanings and connotations of the words.
So if the dictionary entries offer such a narrow definition of a word, why do so many people defer to the dictionary when defending their position in an argument?
When inexperienced writers or debaters defer to the dictionary definition of a word they are trying (and failing) to make themselves sound authoritative on the subject that they are exploring. But when an experienced writer or debater defers to the dictionary his or her intent is use the overly specific definition to distance him or herself from a subsection of the subject that he or she wants to be distanced from.
Oftentimes, the intent of using the dictionary definition is to ignore that a part of a words meaning exists. For example, a feminist might sight the dictionary definition of the word feminism (The theory of the political, economic, and social equality of the sexes [http://www.merriam-webster.com/dictionary/feminism]) to distract people from some of the distasteful parts of the movement by asserting that they simply do not exist because the definition says that they do not exist. But as this video shows the fringes of the movement still exist even though the given definition does not allow for them.
(I do not agree with this man’s point of view regarding feminism in general, but the video shows that crazies do exist within the feminist movement.)
Of coarse, socialism, Islamism, men’s rights movement and many other movements use this same tactic to fool people into believing that only good comes out of their movement.
But why is it wrong to ignore the bad that can come out of a movement?
Assuming that the person doing the arguing for his or her movement of choice is out to make a positive difference in the world, using this tactic makes you seem dishonest and your movement seems dishonest by association. And when people believe you and your movement to be dishonest they will not take your movement seriously. If people do not take you or your movement seriously you will not be able to make positive change in the world.
So when arguing for a movement or ideology you should acknowledged that there are negative associations and show how your branch of the movement is working to fix these problems rather than simply ignoring that the problems exist in the first place.