Defining and using terms in debate and discussion: What are the best practices?

Myself, I love the challenge of puzzling together successful and worthwhile logical concepts for the sake of consensus by means of discussion, debate and arguing. I’ve found that failure to specify a definition for key terms results too often in ambiguous communication. I’ve noticed at times participants inadvertently carrying on two separate conversations as a result of their understanding separate definitions for key terms in the dialog.

As a very simple example:
Bob: “Pass me that tool, Jim.”
Jim hands a wrench to Bob.
Bob: “Sorry, not the wrench. I meant the hammer.”
Explanation: Communication fails at first because Jim assumed that “tool” referred to a wrench. The difference in Jim’s behavior between passing Bob a “wrench” or a “hammer” was exactly the difference between Bob’s and Jim’s definition of the word “tool.”

In the same way, consider the scenario where two people are having a discussion or debate about whether atheism is a religion. Without defining the term “Religion” or “Atheist” how can the speaker’s opinion be verified and validated by his audience when he makes a claim such as: “Calling Atheism a religion is like calling bald a hair color.” (Don Hirschberg) With this phrase the way it is, there is no way to verify whether the key terms “atheism” and “religion” are congruent or not. All we see is the author’s opinion but not the reason for his opinion since the two key terms are lacking definition. Without those definitions, the statement lacks the evidence of incongruity that would provide weight for the opinion.

The problem I have with Common Definitions
There is such a thing as common or popular definitions as defined in the various dictionaries. These function as a sort of default for conversation when the definition is not specifically set by the speaker. They also serve to set the definitions for all the non-key terms. However, the problem with relying on these fall-back definitions for key terms is that sometimes dictionary definitions differ from one to the next. In any case, the speaker may have a slightly different understanding of the term rendering the common definitions useless. The speaker may not even realize that his definition is divergent from the majority. It seems clear, then, that there is no absolute definition or meaning for a term besides that which the author intends.

So, I have an idea I would like to suggest and hear your thoughts on: Let the speaker define all his key terms. Let the audience, assess the arguments validity and soundness based on those definitions provided. This way, there doesn’t need to be any debate on whether his usage of the term satisfies the whim of the audience or anything else. Instead, the argument being made can be evaluated for internal consistency according to the set definition without any ambiguity as to whether the term is being used in a more or less broad way than was specified.

Love to know your thoughts on this and other concepts in setting and using definitions in discussions and debate. Whatever helps the masses to get along!