What is meant by “nature” or “essence”?
I am not a trained philosopher, so any input on here for this topic from a philosopher is appreciated. However, I like to take challenging concepts and explain them so that almost anyone can understand them.
In order to do that, I often find that foundational concepts have to be explained first.
This idea of essential traits and accidental traits is one of those foundations.
In the most basic sense, an essential trait can be said of something that if that trait were to change, would change what that something is.  An accidental trait is one that can change without changing what something is.
To illustrate:
I can draw an object.
What is this?  A circle.
 
 
But what if I draw one on the other side of the page?  Now what is it?
Still a circle, because LOCATION is an accidental trait of a circle.  Its location can change without changing that it is a circle.
 
Now I draw a blue one.
Now what is it?
Still a circle. Why?  Because COLOR is not an essential trait of a circle.  COLOR is an accidental trait.  Changing color does not change what it is.
 

 
Circles can have a lot of different accidental traits.
Now, I am going to draw one more circle.  This time I am going to draw it with four corners.

 
Now what do I have?
A circle with corners?
No.  Now we have a square.  Why?
Because ROUND is an essential trait of a circle.  If you change it’s ROUNDNESS, you change what a you have when you are dealing with circles.
There are other things for which shape does NOT change what they are, so shape is not an essential trait.
This is a circle.  One of the simplest concept we can tackle.
Imagine if we decided to discuss the essential traits of a chair, or a world or humankind or an individual person, or even God?
 
The compiled traits of essential traits is correctly called that thing’s “Essence” or “Nature”. Something’s “nature” is the compilation of traits that are “essential” to it.  “Nature” is another word for this concept.
 
Any of us could debate for hours the essence of God, or even something as simple as a chair.  We could also debate where essence comes from. These are questions that divide the metaphysical views of philosophy, like “postmodernism”.
 
It should be apparent that many of the conversations that we think are political are actually conversations about essence.  Is a fetus a living human being with the rights that come with being human?  What is a male or female?  What are the essential traits of “marriage”?  What is the definition of “consent”?
In theological articles, this has importance… does God even have accidental traits?  Could The Trinity have been “broken” when Jesus was on the cross?  What does it mean that “God is Love?”  Think about how this concept is vital for conversations about the nature of suffering!
I except that many of my other articles will reference back to this one.