Two Is One And One Is None
What Does Two Is One And One Is None Mean?
Redundancy is an engineering term which means the intentional duplication of critical components or functions of a system or plan. Vital parts of the system should have a primary and a secondary / backup to ensure the part works even if the primary fails.
You will often find high levels of redundancy in aircraft systems around fuel, control surfaces and landing equipment. If the primary fails the backup is designed to automatically take over, ensuring the plane stays in the air or lands safely.
How Does Redundancy Work For Preppers?
The phrase “two is one and one is none” simply means that for the most important elements of survival one tool or prep isn’t enough.
You should also have a backup ready to go and ideally it should not be an exact duplicate. This is to avoid the reasons for the primary not working also preventing the backup from working.
For example, a Bic lighter is great for easy fire making but over time they can slowly leak fuel, making them almost useless in an emergency. The button can also be accidentally pressed in your pocket / bag, leaking fuel much faster and even without leakage the fuel will eventually run out with use.
If you need fire and the lighter fails, simply switch to your ferro rod, storm proof matches or Fresnel lens.
Fire
Accidental Bic lighter fuel leakage can be easily combatted with an EXOTAC Firesleeve or the cheap clever trick which secures the lighter button with a mini cable / zip tie.
Ferro rods are a great fire starting option and you could have two ferro rods exactly the same, in case you lose one, but it’s far more efficient to have a Bic lighter as a quick primary fire starting method and a ferro rod plus striker as a backup.
Ferro rods are simply a combination of Iron and Magnesium so there isn’t much to go wrong and if they get wet they still work. Some of the larger rods are capable of lighting 1000s of fires. We recommend the überleben Hexå 1/2” by 6” Ferro Rod.
Having both gives you the capability for quick but ultimately unreliable fire making and slow but almost guaranteed fire making over time.
Check out our guide to fire starting.
Water
On the move you need to have knowledge to find water, collect it, filter it and purify it for drinking.
A water filter and purifier like the Grayl Ultrapress is great as a primary water purification option but it’s also handy to have some water purification tablets with a container as a backup.
At home the weight of water is less of a concern, so you can dive into rain water collection, high volume water storage and high output water purification.
The LifeSaver Jerrycan is a great primary option but it’s also handy to have a large firesafe pot as a backup for water purification via a rolling boil for a few minutes.
Check out our guide to water collection, filtering and purification.
Location
“Bugging in” is almost always the best option. Your home is a secure place where you know the layout, you have all of your supplies, your preps and it is easier to defend than a makeshift camp in the woods.
But what if you have to “Bugout” and evacuate your home, because you have no other option? This is why some people have a bugout location as a backup.
At the extreme end it could be a fully stocked cabin in the woods but for most people it is a family or friend’s house.
The important point is to have a plan for where to go and how to get there in an emergency / SHTF ahead of time e.g. local flooding, storm roof damage, power outage, no mains water etc.
Skills
There is usually more than one way of achieving a survival goal and this is where knowledge comes in e.g.
You have a ferro rod but have lost your striker. Any 90° metal edge on a multitool will work.
A drybag is great for keeping the contents of your bag dry, but it it can also be filled with air to make a pillow or to carry a volume of water bag from a water source.
Readymade tinder for fire starting is super handy, but what if you run out? A Coke can or Altoids tin can be repurposed to turn cotton or wood into charcoal using a fire.
You haven’t got any cordage left but plastic bottles can be found everywhere. Using a knife and stick they can be turned into a surprising amount of cordage.
Try to read up on the areas of survival or watch the huge volume of prepping and survival videos on YouTube.
Do You Need Redundancy On Every Element Of Survival?
There is no need to have redundancy on every element of survival, no matter how tempting it might be.
Elements such as cordage, duck tape and cotton material are unlikely to fail on you although you can of course lose them or run out.
If you are in a group the rule can have a slightly different meaning as well, for example a family bugging out. You only need two ways of making fire across the group so each person doesn’t necessarily need a primary and a backup of the essentials.
Murphy’s Law
Murphy’s Law states that “anything that can go wrong, will go wrong”. Sooner or later it rings true.
Things wear out, break, can be put down and forgotten, get wet, or not even packed in the first place.
Starting with two preps for fire making means you are pretty likely to still achieve fire, even if one of the preps runs out of fuel, gets wet, breaks or is lost.