by Lazarus Black
Both. But the distinctions between are rarely discussed amongst those espousing one over another. In fact, they are each normally described by their opponent with derision and bile. They are seen by some as extremes at either end of the same scale of story-telling techniques.
I don't. They are two different techniques that must integrate correctly to tell the best story. Eschewing one over another is just refusing to use both hands.
The Two Hands
Outlining: A plot is the series of events that occur through a story, from beginning to end - hopefully in a manner where most questions are answered and problems are solved. These events, called plot points*, measure the progress of the story and some argue that no plot points equal no story. Outlining is listing these plot points in sequential order of reading. An outline may be as simple as the inciting event and the conclusion. Or it may be hundred of points long. In this way, the plot is structured before most of the words have been written.
Exploratory Writing: Writing directly from the imagination as inspiration arrives. That inspiration can come from any process, especially plot points and outlines.
What is the Difference in How They are Used?
Plotter: A Plotter is a writer who plans out their story, point-by-point, from beginning to end, in an outline of some form. They then fill in the gaps using those points as inspiration for exploratory writing between them. I've never heard a Plotter argue that they never use exploratory writing.
Pantser: The term is an abbreviation of "Writing by the seat of your pants". This version prefers exploratory writing without using use plot points for inspiration. Instead, using only what was written beforehand to "write into the dark" - meaning unknown conclusion - until something inspires them to stop. Pantsers let their imagination flow in the moment on a wing and a prayer, often claiming to never adhere to a plot (to the point of insinuating they are better writers because of it). But that definition would be redundant to Stream of Consciousness writing that is already exploratory writing without considering plot points - even eschewing them in some cases.
Can't We All Just Get Along?
Due to some awkward perception in and out of the writing community, there is some superiority believed about those who "don't plot" to the point that even those who do will deny it. But after a lot of practice, an author may be able to internalize a preferred plot structure and manage its outline entirely in their head and heart. So when they sit down to write from start to finish, they may not imagine that they've plotted at all. And the outside observer may come to the errant conclusion those authors don't plot at all. And there are ways to manage a flexible outline that, again, can look and feel like there was no structure.
There is a similar situation in the art community where some people believe drawing a human being without a model for reference is somehow a rare and superior skill. The reality is that some artists have memorized the human body enough to replicate it to their own preference. They don't use a model any more - but they built one in their head to always use later. But that skill alone doesn't make great art. In fact, that skill has been used a crutch by artists to avoid exploring more body types and emotional expressions.
Unfortunately for those hailing pure Pantsing (Stream of Consciousness) as the epitome of the art-form, market research is against them, as the overwhelming majority of readers do not enjoy works without a structure.
Structure?
A plot is just how the story progresses. Plot-points are the milestones, where things change in the story (e.g., reversals). Without change, the written words are not a story, but merely a description.
The structure is the purpose and order behind the plot-points — how, when, and why the events occur in the order that they do. Just as structure keeps a building from collapsing, it also keeps a reader engaged in the story from beginning to end. Plot-points include clues and discovery and foreshadowing and revelation and so much more. Those are easier to manage in an outline and easy to forget or entirely omit without one.
Which is why authors like Neil Gaiman explain that one way to write is in multiple drafts.
"The point of the first draft is to get the story down. The point of the second draft is to rewrite the story as if you knew what was going to happen all along." - Neil Gaiman (paraphrased)
This method enjoys the entire exploratory writing process, but then recognizes that it could be so much better if the plot-points were in some kind of structure. Obviously, this is easier if one can write from an internalized plot structure, and exasperatingly difficult if one cannot.
So, a writer needs to do both. Back and forth. Alternating between methods until the story is perfect.
More practice means fewer drafts (usually).
What About You?
As for me? It depends on the story.
Sometimes, an idea comes for the beginning middle or end as a powerful plot-point I want to base a s tory around. If I know one of them, it's pretty easy to figure out what the other two should be (because I focus on reversals).
Sometimes, I only have a character or a theme or a scene in mind. In those cases, I will sit down and do exploratory writing until a plot-point emerges and captures my imagination. Then, leap away from it and build out my outline.
For each plot-point, I write what that point changes in the story. What was the story before and what is the story afterwards. This before-after pairing tells me what the scene should be. I write the before part and then explore all the fun details and character parts aiming towards the after part. Then I move to the next pairing and the next. Over time, there may be deviation, but I'll see it and address it. Maybe the deviation is better than the original outline and I have to update it. This results, I feel, in a perfect blend of structure and organic experience to both write and read.
Every author has their own method. I know authors who are horrified at mine. LOL. But I find as much enjoyment in constructing my plot-points as in parleying Chandleresque quips between foils.
Do what works for you.
* e.g., Reversals, revelations, introductions, etc.