Easy Does Not Equal Simple, But Simple Is Often Easy

This language ramble focusses on a subtle, but important distinction of usage in the English language, as opposed to some computational language. I want to add some clarity to the use of the words “simple” and “easy” that might by synonyms, but then again, they might not.

The point is that these words are often used with less rigour than is helpful, thus muddying the mental waters.

Easy – Requiring Little Effort

The English word “easy” is the adjective formed from the word “ease”. This word arrived in English from the Old French word aise (or eise) meaning “comfort” or “convenience”, which in turn, was derived from the Latin word adjacēs meaning “vicinity” (this is also the root of the English word “adjacent” meaning “next to”). In modern English, easy means “exerting little or no effort”.

It is interesting to observe that one of the opposites of the word “ease” is “dis-ease” – a condition in which a person suffers from some kind of sickness that increases the amount of effort needed just to get through the day, thereby removing their ease of life.

Nowadays, the modern meaning of “easy” refers directly to the low level of effort required either to achieve a result or to maintain a state of being (hence the phrase “taking it easy“).

Simple – Having a Minimum Number of Parts

The English word “simple” is derived from the Latin word simplex which literally means “having one fold or braid”. The Latin prefix sim- means one and the suffix -plex comes from the Latin plicāre, meaning to fold, braid or weave. Hence duplex means “having two folds/braids” and complex means “to encircle or encompass” (by virtue of having many folds/braids).

It was not until 1715 that the word “complex” was first used with the modern meaning of “not easily analysed”.

We can see then that the word “simple” refers to the number of constituent parts. The lower the number of parts, then the “simpler” that thing is.

Easy, Simple and English Usage

The problem here is that in common English usage, “simple” and “easy” are often used as synonyms. From one perspective, this seems like an acceptable substitution in that any sufficiently simple system will usually be easy to understand and therefore use; however, I need to demonstrate that this is largely a one-way equality.

Simplicity often implies ease of use, but ease of use does not necessarily imply simplicity. Here, we must look carefully at what is being implied by the use of the words “simple” and “easy”.

From Complex To Simple

Knowing that complex means “not easily analysed”, it should become clear that in order to understand a complex system, you must expend a large amount of analytical effort over a prolonged period of time.

Take for instance the analytical effort Albert Einstein invested before arriving at the equation E=mc2. Not only did he need to allow his mind to abandon any ties it might still have had to Newtonian mechanics, he then had to build on the non-intuitive (at the time) ideas of Lorentz, Poincaré, Planck and others.

His now-famous equation is childlike in its simplicity, yet the amount of effort required to derive it was enormous.

This is just one of many possible examples demonstrating that reducing complexity down to simplicity requires a considerable investment of time, effort and perseverance.

The objective here is to reduce the number of parts down to a minimum; and to borrow from Albert Einstein again, “A system should be as simple as possible, but no simpler“.

From Difficult to Easy

Think about the amount of effort you put in to mastering a particular skill that you now take for granted: for instance, learning to drive. I passed my driving test 30 years ago now, and I can honestly say that I have only scattered memories of exactly how much conscious effort I had to initially apply in order to coordinate the steering, brakes, accelerator, clutch and gear-shift.

However, through repeated use of these skills, I can now drive a car without the need to apply any conscious thought towards the operation of a car’s controls. It has become “easy” in that after many years of practice, I need to apply very little effort to achieve the desired result.

At the time of writing this blog, my daughter is about to take her driving test, and it has become apparent to me that an activity I take for granted, is one she finds difficult: for instance, driving through a busy 5-way London intersection with traffic joining and splitting off in multiple directions is something that does not bother me at all, but makes her very anxious. The difficulty she is experiencing is simply due to her having 30 fewer years driving experience than I do.

But I must not allow my familiarity to lull me into the false idea that because I find something easy, that it should therefore be easy for someone else (especially a beginner). I certainly cannot remember exactly how much time and effort I had to exert whilst learning to drive, but seeing the effort my daughter is putting into it, I can appreciate that my perception of driving being “easy” is only due to my familiarity with that activity and has nothing to do with whether it is actually simple or not.

So the transition from “difficult” to “easy” requires an investment of time, effort and perseverance; with the objective being to develop skill and mastery of that task. Once this mastery has become routine, you will then perceive the task to be “easy”, but will probably have forgotten the investment required to achieve it.

Easy ≠ Simple, But Simple Usually = Easy

What simplicity and ease have in common is that both require a prolonged application of time and effort to achieve; however, where simplicity and ease are quite different is in their objective:

Simplicity is focussed on reducing the number of component parts in a system down to a minimum
Ease of use is focussed on reducing the amount of effort required to achieve a particular result down to a minimum.
Once you have achieved simplicity, you will often also have achieved ease of use. However, we should be aware of a potential confusion that can launch itself upon us from two different angles:

  1. Via the simplicity
    Once a system becomes simple, it often becomes easy to understand. Therefore, it appears self evident that a simple system is an easy system. Well yes – but with a caveat.
  2. Via familiarity
    Once you become familiar with a system, the amount effort needed to operate that system is significantly reduced; therefore, isn’t it obvious that “easy” and “simple” are synonymous?


Point 1 has forgotten (or is unaware of) the often very large investment of effort required to move from complexity to simplicity. It is certainly true that a simple system is almost always an easy system (assuming of course that the minimum number of component parts are properly understood); but only in trivial cases do simple systems start as simple systems.

Point 2 has forgotten two things: 1) the prolonged amount of time and effort invested in becoming familiar with the system, and 2) that familiarity often hides the fact that that system has not necessarily been reduced down to the minimum number of components.


If you want to your complex software system to become simple, then I can promise (with a high degree of certainty) that for any reasonably sized software system, you will need to expend a large amount of time, effort and money to reduce the complexity down to the minimum number of components.

However, once you are familiar with a software system, that familiarity can create the illusion of simplicity. In this situation, someone who lacks this familiarity will see your system’s lack of simplicity far more readily than you will.

The flip side though is that once you have gone through the blood, sweat and tears reducing a complex system down to a simple one, that system will necessarily be much easier to use than a complex one.

So ask yourself this: does my perception of ease of use come from familiarity that has been developed over a long (and probably forgotten) period of time, or does it come from the fact that the system has genuinely been reduced down to the minimum number of components?

Easy does not imply simple, but simple usually implies easy.

Chris W