So, I came to this forum with a very narrow view of "exist" and have, with the help of some of the users (and some on a philosophical forum), resolved my philosophy and physics. This may seem pedantic, tiring, or even trivial to some. However, it's vitally important. The inability to distinguish an existent from a non-existent or an entity from a non-entity is exactly what got science into such a pathetic state. Without further ado, here we are.
Concrete Entity: Shape and location
Abstract Entity: Shape
Existent: A concrete entity or a relationship among concrete entities
Existent is the more general category. It can be subdivided:
1) Independent Existent: A continuous, indivisible entity.
2) Concrete Dependent Existent: A collection of independent existents (entites) with one or more particular set(s) of spatial arrangements.
3) Abstract/Conceptual Dependent Existent: A collection of independent or concrete existents with two or more consecutive set(s) of spatial arrangements.
To saving typing/talking you can just shorten these to "independent, concrete dependent, abstract dependent".
Thus, tables and cows fall into category 2. Love, justice, and consciousness fall into category 3. It may be difficult to understand the difference between 2 and 3 at first glance. The important thing to realize is that 2 is a *static* relationship whereas 3 is *dynamic*, the keyword is "consecutive" implying time. For the sake of discussion lets assume that the atom is the fundamental constituent, the argument works whatever we call the fundamental constituent. For instance, you may refer to a particular collection of atoms as a tree. The atoms are not always in precisely the same location, but you can assign a set of locations for all the atoms such that you still identify it as a tree if all the atoms are at one of the locations you assigned it. Mathematically this could easily become outrageously complicated, but conceptually it is not hard. So if some bark gets scraped off and a few trillion of the atoms are carried to the Andromeda Galaxy you still identify the tree because you can decide that, as long as a certain minimum number of atoms remain at some minimum proximity, it is still a tree. If the tree is chopped in half you may not identify it as a tree anymore although the two pieces lie within inches of each other. Instead of a tiny fraction of the atoms being separated you're now dealing with half the atoms in the tree, which may be above your minimum number. No matter how complex, simple, lengthy, or concise your criteria, it is always static. You always look at all the atoms' location simultaneously and decide right then if it's still a tree.
On the other hand, category three is dynamic. Love is not simply a picture of specific atoms at specific locations whether they are in someone's brain or body or whatever. It takes more than a picture of two people at some proximity to understand love. There must be interaction, motion, etc. Love is not just a candlelit fancy restaurant with two people sitting at a table. It is one person talking to the other, looking at each other, thinking, planning, feeling, etc. Consciousness is the quintessential example. There is simply no single set of spatial locations of entities that results in consciousness. Consciousness involves consecutive locations, motion, interaction, etc. Justice is not simply a courtroom, it is an action or set of actions. It is a judge pronouncing sentence or a revolutionary fighting for the neglected common folk. Category three is the ubiquitous experience of everyday, our lives, our experiences.
Physicist: This is a pen
Mathematician: It's pi*r*h