A force is an influence or a potential set into action. If you’ve ever moved your body or anything else, you have experienced a physical force to do so, originating in your muscles. A wood splitter uses hydraulic force. A lawn mower uses the force of expanding gases to spin its blade. A refrigerator uses magnetic forces produced by electricity to turn a compressor and chill the interior.
A deadly force is one that might potentially produce an injury leading to death. There are many such forces, found in many places, from wood splitters to lawn mowers to the movements of our own limbs to the voltage in our power lines. Usually, these deadly forces do not produce such injuries, because we recognize that they must be employed carefully, and under strict control. On the other hand, accidents also happen on a daily basis, and they sometimes lead to death.
You choose to use deadly force when you mow your lawn, drive your car, or shoot a firearm. They are all comparable. In matters of self defense, however, that deadly force is employed in a way that’s likely to stop an attack upon you. Coincidentally, such a use of deadly force is also likely to injure your assailant. Since it is deadly force, there is also a chance that your assailant may die from his injuries.
In order to be prepared to defend yourself when seconds count, you should take some time now to think through your willingness to apply deadly force during those seconds. In the course my wife and I attended at Front Sight, there was a lecture on moral and ethical decisions relating to the use of deadly force.