Two is One and One is None | The Power of Redundancy

There are plenty of quotes that endure in the prepping and survival communities, but one of the most notable is Two is One and One is None. It’s not just a catchy phrase either- it is an excellent mantra to live by when the stakes are high. This makes sense when you understand what it means and where it came from. It is a quick phrase that embodies the importance of redundancy in planning, preparing, capability, and gear.

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“Two is One and One is None” Meaning

Two is One and One is None means that you should expect and plan for at least one thing to go wrong. It refers to assets: weapons, equipment, survival gear, plans, and even people.

This means that it is a pessimistic view that things will work out, and that makes sense considering the quote is loosely based on Murphy’s law. Murphy’s law, of course, states that anything that can go wrong will. This is why the numbers are one less – you are meant to assume that one thing will go wrong, break, go missing, etc.

Even the most careful plans and robust equipment need backups.

When you add backups to your supplies, plans, people (anything, really) it is called redundancy.

Redundant Gear and Supplies

Our friends across the pond use the word ‘redundancy’ as another word for getting fired, but redundancy isn’t always negative. There are two main definitions of redundancy:

  1. British: the state of being no longer employed because there is no more work available.
  2. Engineering: the inclusion of extra components which are not strictly necessary to functioning, in case of failure in other components.

Obviously, we are focusing on the engineering definition here and are not talking about getting anyone fired.

The engineering definitely of redundancy exactly explains what ‘Two is One and One is None’ means. In military and survival situations, you will want additional supplies, plans, and skilled people in case of failure ‘in other components.’

Some of the best gear and supplies to stock up on for redundancy are tools that align with The Five Pillars of Survival. This is why fire starters are suggested alongside lighters in almost every survival kit. Food and water are other areas where multiple supplies are included- so that one failure doesn’t cause catastrophe for your survival plan.

Redundant Capability and Skills

In the same way that extra supplies can give you redundancy in a survival situation, you can have skill and capability redundancies. This can be either you learning redundant skills (like knowing how to create and use a bow drill and a fire plow) or teaming with prepper groups that have people with skills that overlap.

In my opinion, the better option is to learn redundant survival skills yourself since that is in your sphere of control and gets you closer to self-sufficiency (a common prepper goal). There are unlimited survival skills to learn and it’s almost always a good idea to pick up new ones even if they are redundant.

Prepper communities and groups are great, and it is always a good idea to consider the skill sets of people in your groups to ensure you have redundancies in place. If you only have one HAM operator in your group, you may end up in a bind when it comes to communicating in an emergency.

“Two is One and One is None” Quote Origin

Two is One and One is None is an old adage attributed to the US military, and specifically to the Navy Seals. It is tough to pinpoint the exact start of the quote, but it has been referenced for at least half a century. A few people have claimed that it started with the Army Rangers, but the saying is more engrained in current Navy Seal culture laying doubt to this claim.

The idea, however, has been around for as long as people have been preparing. Soldiers and survivalists typically carry multiple knives. Hikers carry extra days’ worth of food, in case something goes wrong. Teddy Roosevelt is known to have had at least half a dozen eyeglasses on him when he led the Rough Riders into battle. All of these are redundancies in action and demonstrate the ‘two is one and one is none’ philosophy.

One of the oldest examples is right out of the bible.

Bible Reference

In the book of Ecclesiastes in the Bible you can find some guidance about two vs one:

“Two are better than one, because they have a good reward for their toil. For if they fall, one will lift up the other; but woe to one who is alone and falls and does not have another to help. Again, if two lie together, they keep warm; but how can one keep warm alone?” – Ecclesiastes 4:9-12

Most people interpret this verse from Ecclesiastes as God placing people in their lives to assist them, and to refuse assistance is to refuse God (or God’s will).

Even if you think some are reading a bit far into that verse, it’s still plain to see that it states in plain text that two is simply better than one.

Redundancy with Versatile Equipment

One of the easiest ways to get redundancy with your equipment is to use versatile equipment. Multitools are a great example of this. A multitool can be the redundant option for a knife, scissors, pliers – lots of different equipment all at once. It may not be the best option for any of those functions, but its versatility makes it great for weight and as a secondary option.

It is almost always better to have your redundant gear accomplish the goal as your primary gear but in a slightly different way. This is in case the primary failure is due to a shortcoming of the equipment itself. We can go back to the example of fire steel being a backup to a lighter.

Quote Variations

You’ll find a few variations of the main quote running around out there, including:

  • One is None and Two is One – Just a few people misquoting or swapping the order around.
  • One is None, Two is One, Three is … – Some people ask ‘well what about higher numbers?’ The answer here depends on what we are talking about. If it’s ammo, then it’s still not enough. If it is flashlights in your pocket, then you are a flashlightaholic and a borderline hoarder.
  • Three is Two, Two is One, One is None – In reverse order, sometimes people will start at even higher numbers. This can lose some of the impact/meaning if you start at too high of a number since you are only subtracting one.

Whatever way you want to say it, as long as you understand the meaning of the quote then anything goes. Intent trumps semantics any day.

Adding Resource Dispersal

When you have redundancies (or anything that you may rely on, for that matter) another important consideration is resource dispersal. Spreading out your resources reduces the chance that they’ll all fail on you at once. This is another military practice that works its way into emergency preparedness.

If you keep all of your survival gear and long-term food storage in one area, and that area gets destroyed (say by fire, flood, theft, etc..) then you are out of luck. If you store your supplies in multiple spots and one of them gets destroyed, then at least you have the other supplies. It’s more likely that some of your supplies will be destroyed, but significantly less likely that all of them will be destroyed. You can see how this works in tandem with the ‘two is one and one is none’ philosophy.

You can learn more about resource dispersal and how to actually implement it in our full write-up: 3 Ways to Use Resource Dispersal to Improve Your Chances when SHTF

The Final Word

Two is one and one is none is a solid quote and a great philosophy to keep in mind for preparedness. You might encounter some preppers that argue the semantics, or even call it a fallacy- but they’re just overcomplicating it or being controversial. The philosophy holds water in every situation if you don’t box it in and take it literally.

If you haven’t started prepping yet, then what are you waiting for? Get started prepping now. If you don’t know why you should be prepping, we have you covered as well: Why You Should Prepare for Emergencies. Here are a few other good reads you may be interested in:

Keep exploring, stay prepared, and be safe.

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Two is One and One is None

Rusty Collins

I am an engineer, Air Force veteran, emergency manager, husband, dad, and experienced prepper. I developed emergency and disaster plans around the globe and responded to many attacks and accidents as a HAZMAT technician. I have been exposed to deadly chemical agents, responded to biological incidents, and dealt with natural disasters. Check out my full story here: Rusty's Story

2 thoughts on “Two is One and One is None | The Power of Redundancy

  • About 12 years ago I mentioned Two is One & One is None when one time I bought extra Iced Tea mix (after the store was out the week before) to my wife. I explained how we used 2=1 & 1=0 while I was in the Navy (not SEALS but I was a Rescue Swimmer). She thought that was great thinking. When we started prepping during the Obama Dictatorship she kept that phrase in mind every time we went shopping. Even today we still use that phrase.

  • In many engineering designs I used the “belt and suspenders”design phlosophy where-in if one failed the other prevented you from losing your Pants. This has parallels to your ‘two is one and one is none’ philosophy.


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