What does this mean?
"defend yourself without a firearm"?
The reason I say this is to be careful of your words, keep in mind politics. There is plenty of people that would like to restrict firearm possession in general, or in various locations, and say things like it does not interfere with your right to self defense.
This is untrue because defense against a firearm without a firearm is quite difficult, and many bad guys will still have firearms where they are not supposed to. As will the few who are allowed to have guns in such locations who either lose that firearm to someone else, or go postal themselves (as both LEO and security personnel sometimes do.)
As for self-defense without a firearm being a requirement, that is unfair. It certainly is smart and should be encouraged, but there is a number of people that even trained would not be very good without a firearm, and can still benefit from having one. Take a disabled person, perhaps one that cannot walk, maybe has other injuries, yet can still manage to use a firearm.
Now the less proficient one is at retaining their firearm the more important it is that they keep it unknown that they have a firearm to take.
It is unfortunate that one must often identify themselves as someone that carries a firearm to defend and promote the right, or be silent and see the right dwindle and be lost or heavily restricted.
The same people that should probably not announce to everyone that they have a firearm can often be the people that are best served by a firearm as an equalizer. Being an ideal example of just why firearms are so important for self defense.
We had a great video on here of a guy shooting a gun and reloading with his feet. While this would be dangerously stupid for most people, the guy lacking arms has resulted in him developing extremely good dexterity with his toes.
http://www.youtube.com/watch?v=tlMz2sCDCA4
He certainly could at least take up a defensive position and defend himself.
I have heard of and seen similar cases of people who have lost limbs, or been born without them, learning to use their legs and feet as hands.
So yes the ability to defend yourself without a gun is a very important skill. As is retaining a firearm.
However it should not be viewed as a requirement, but rather an additional useful skill.
One thing you will find with a percentage of strong, healthy, body builders, martial artists, and some fitness nuts is a distaste for an equalizer.
These people that put so much work into being strong, healthy, and capable, like the perceived advantages they have in a physical altercation.
Any 'moron' can just as easily kill them with no skill, experience, wisdom, discipline, etc by using a firearm.
It drops the value of what they have down a few pegs. This causes some of them to despise that guns exist or are available, or be less enthusiastic that other people have them.
However guns exist, they will exist, and a good percentage of violent criminals encountered will be armed with them. This requires someone to also have a gun to defend themselves, even if they are one of the most physically capable.
If you do not have a gun you cannot really effectively and reliably defend yourself as an individual from many of the most common attacks, those made by criminals armed with a gun.
Now one should not rely on a gun as a magic talisman. A gun does not keep someone safe. It is a tool that gives one the means to project pieces of metal.
Mindset along with other skills are more important, and prevent the need to even use a gun most of the time, and leave one in a better position if they do need to use one.
Being good at physical self-defense increases ones odds of success, both with and without a firearm, and is a valuable skill.