My argument is this: simplicity is not the absence of something, but rather, the presence. A simple home features a few pieces of furniture and no overflow of items or clutter. You can say it is simple because of its lack of clutter, but in essence, it is simple because of what it has, and only what it has. Life is like this. Look at your daily routine.
A life is simple based on what it has. Rising time. Coffee time. Interactions with people. Phone calls. A long run. Make your list of what you have to measure simplicity.
Don't make a list of what you don't. We do not look at a piece of artwork and say "Oh, this landscape is lovely because it does not have a vacuum cleaner in it."
We say, "Oh, this landscape is lovely because of the colors in the sky and the trees on the horizon." We notice what it has and then remark on its simplicity, its beauty.
Simplicity is something everyone can appreciate. What makes it special is that every person has a different version of simplicity.
Years ago, I thought that simplicity was something you could define clearly, to a standard. You could measure everything against it. "He has achieved simplicity in his work life, but not his home life."
But simplicity is not a destination, or an end point, or a grade on a test. Simplicity is mutable and set against the backdrop of life, which is also mutable. A goal of simplicity at 15 is different than at 45 and a goal of simplicity at work as a creative director is different than the goal of simplicity at work for a family physician.
My argument is that simplicity is the presence of things: tangible and intangible. It is up to the individual to determine whether they are living it or not. It is up to the individual to revisit the concept of simplicity in life throughout their life, as life changes and so does simplicity.