This video by San Jose police officer Leroy Pyle provides an excellent demonstration of the difference between “semi-automatic” and “automatic” firearms:

“The Truth About Semi-Auto Firearms”

In particular, Officer Pyle does an excellent job of showing that two guns can have nearly identical inessential cosmetic features (such as the material the stock is made of), but differ in this one essential feature (semi-automatic vs. automatic), making them fundamentally different guns. Conversely, two guns can have the same essential features (i.e., both be semi-automatic), but one can be made to look very menacing and the other very innocuous simply by changing a few inessential cosmetic features.

In my experience, there are even some Objectivists who lack this basic understanding of the difference between automatic vs. semi-automatic weapons.

This is a nice real-life example of the importance of good epistemology, and in particular of defining by essentials. And we can see the dangers of failing to define by essentials when policy makers talk about banning “assault weapons”, which is a bogus concept created grouping together firearms based on these inessential cosmetic features, rather than the essential ones.

Even now, there are some Republican Congressmen (not Democrats) who wish to reinstate the expired “Assault Weapons Ban” based on precisely this bogus concept. And given the incoming Obama Administration, this bill may become law.

As a corollary, this is also a concrete example of why a proper defense of one’s political freedoms depends on upholding a proper rational epistemology — and more generally a proper objective philosophy. Fortunately, that epistemology and that broader overall philosophy is already available to us — we just have to be willing to use it.

(Video link via Howard Roerig.)