Many years ago when the world was mapped, a couple of people looked at the papers and noticed something interesting. They said (I'm paraphrasing), "Hey, it really looks like South America and Africa fit together sort of like puzzle pieces."
The educated folk likely said something in return like, "Well, it would look like that to unschooled people, but we study this for a living and obviously the continents do not move. We'd feel it, would we not? Come now, let the experts do our jobs, shall we?"
Condescension never was the best way to make a point.
We now know that the "common sense" contingent were correct and the nose-thumbing that ensued when the proof rolled in must have been epic. Situations like this where intelligent, well-read, non-professionals (or just lay persons) have made observations and been right have given way to today where people just assume that they're correct because something seems "common sense" in spite of not just authority speaking, but in the face of (sometimes literal) mountains of evidence to the contrary. This often leads to the Galileo Gambit being used by the underdog.
Ease of understanding seems to be the hinge for discussion on debatable subjects. Take the internet film Zeitgeist as an example. This film spews forth information at a breakneck speed with nary a reference source cited. All it does is make claims that people who don't know any better - and likely won't take the time to research it themselves - will find interesting and, ultimately, convincing.
It's Tower 7, man, that's the key.
Simple ideas can be powerful but make no mistake, common sense can lead us far astray as well. Every time I think of this topic, I'm reminded of an article by P.Z. Myers on Mexican Blind Cavefish. It is a fascinating read that rebuts the sensible assumption that fish who live in the dark don't need to see, therefore evolution selected against eyes, ergo they no longer have eyes. The article states:
Because hedgehog (a symmetry gene) and pax6 (a development gene controlling the eye, jaw, teeth, etc...) are negatively coupled to one another, one can be expanded only at the expense of the other, and what is going on in the blind cavefish is not selection for an economical reduction of the eyes, nor the accidental loss of an organ that has no effect: It is positive selection for a feature (more sensitive jaw and tastebuds) that is only indirectly related to the eyes.Common sense gone astray, indeed. This explanation is so much more interesting and has so much more depth to it, but it is not something that can be pitched in five seconds. You actually have to listen and pay attention in order to understand.
This idea can be slathered all over so-called "alternative" medicine. So much of "alt.med" can be explained by people who "just know" or think treatment X just "sounds good/right". What's that? There's a tiny amount of mercury in vaccines? Mercury is toxic? Well that can't be good, can it? That's just common sense.
It is an uphill battle we face to talk people away from what seems simple and obvious and towards an answer that is nuanced, subtle, and sometimes messy. Getting the general public to be comfortable with uncertainty and perhaps even (gasp!) changing their minds from time to time with the appearance of new, better evidence would bring forth an intellectual revolution perhaps unseen in history since the Enlightenment.
Not a bad long term goal, eh?