I attended a 3-hour lecture/seminar/symposium several weeks ago. While I am unable to disclose the location of the event, the subject matter covered, and the types of attendees; I will preface this discussion with stating that the attendees were typically 50+ years of age, highly educated, multilingual, of both genders, and from different nations. No, it wasn't a Toastmasters meeting. About 15 minutes into the lecture, the speaker began to use the term, "common sense." Forty-five minutes elapsed and the audience began to notice that phrase being used about every 5-8 sentences. I look around the room and noticed that my fellow attendees began to look at one another with a furrowed brow each and every time the lecturer used that phrase. After about an hour, I finally spoke out and asked the lecturer to define the phrase, "common sense" in the context in which he was using it. He was very succinct with all the terms and phrases he had so far used; however, that one appeared to me to be nebulous at best. He gave a long-winded explanation that ultimately culminated in "...what every body knows." After the explanation, he spoke another 15 minutes before using that phrase again. The speaker was American. So am I; however, the individual seated to my left, also American, looked at me, nudged me with his elbow and asked what the speaker meant. No one-NO ONE-questioned the speaker's last three sentences that preceded that phrase. I quickly raised my hand, politely interrupted, and asked the speaker if he meant to state common knowledge instead of "common sense." He said it was the same thing. I stated that it was not the "same thing." The speaker asked me to elaborate. Well, since I had already interrupted the lecture, AND it was already construed as a diatribe based on the tone of the speaker's voice, I promptly offered a delineation of the difference. "Common sense," as it is frequently used by Americans, is a misnomer such as the phrase, "near miss." "Near miss" should be NEAR hit or collision as frequently used in the context of automobiles. I stated that "common sense" refers to what everyone knows. Well, if it is known by "everyone," as the speaker alluded, then it should be termed as common knowledge. The speaker, amused by my seemingly superfluous interruption, chuckled coyly and stated, "that's what I just said." I asserted that if something is common knowledge, then everyone in this room should understand most of what you have spoken about the previous hour. I then asked a show of hands how many people have, so far, understood what the speaker has said-so far. I counted 17 attendees. With a restricted attendance of 100, that's 17%. I continued to offer that common knowledge has many factors such as age, culture, gender, nationality, ethnicity, religion preference, political party affiliation, method of upbringing, education just to name a few. Even if the sample population had ALL those aforementioned factors in common, not all will comprehend common-knowledge, care to understand them, or even care to simply know about them. I undermined the speaker's lecture; however, it was eminent to me that it was not headed the direction he intended based on the audience's reaction. He struggled with his notes for a few minutes and resumed speaking. He avoided that phrase for the remainder of the lecture and it was clear that his discussion never gained momentum. I attempted to approach him to continue the discussion after the lecture but he quickly darted away.