Since what many call the greatest philosopher of the 20th century said that there is no such thing as an essence which is a group of essential properties or a single property, let’s prove that they exist.
- Either we give all entities a uni(Q)ue name or we (G)roup entities into categories and (N)ame all entities that belong to that category by the same name.
- We cannot give all entities a unique name.
- Therefore we must (G)roup entities into categories and (N)ame all entities that belong to that category by the same name.
- Therefore, we must use a criteria for grouping them based on something all (E)ntities have.
- All (E)ntities are entities that have (P)roperties.
- Therefore, we must use a criteria based on the fact that all entities have (P)roperties.
- Either we define an entity based on all the properties it can (H)ave, or we define an entity based on (S)ome of properties it can have.
- We cannot define an entity based on all the properties it can (H)ave.
- Therefore, we define an entity based on (S)ome of the properties it can have.
- We can either define an entity based on the properties it can (~M) have or the properties it (M)ust have.
- If we define an entity based on the properties it can have, then it’s (P)ossible that A1 has B and A2 has ~B.
- An entity cannot have contradictory properties (~P).
- Therefore, we define an entity based on the properties it must have. The name for those properties are essential properties.
Q v (G ⋅ N), ~Q, ∴ (G ⋅ N), ∴ E, E ⇾ P, ∴ P, H v S, ~H, ∴ S, ~M v M, ~M ⇾ P, ~P, ∴ M
Another way to prove the existence of essential properties is through the reductio ad absurdum. For the sake of argument let’s imagine that Hillary Clinton wins the 2016 election:
- The (P)resident of the United States is defined as a (M)an.
- (H)illary Clinton is a (W)oman and (B)rad Pitt is a man.
- All women are not men and are not (H)ermaphrodites.
- Hillary Clinton is president and Brad Pitt is not president.
- Therefore, the President of the United States is a man and not a man.
P ⇾ M, (H ⇾ W) & (B ⇾ M), W ⇾ ~M & ~H, (H ⇾ P) & (B ⇾ ~P), ∴ P ⇾ M & ~M
In other words, if we define entities based on accidental properties, then our beliefs lead to contradiction. Finally, another argument for the existence of essential properties is that they are the only way that our beliefs can avoid contradiction.
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All entities that have the same (N)ame belong to the same (G)roup.
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There would be no distinction between (A)ccidental and (E)ssential properties iff there were (P)reexisting groups where each member had the same properties as every other member except for location in space.
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It is not the case that there are preexisting groups where each member has the same properties as every other member except for location in space.
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Therefore, there is a distinction between accidental and essential properties.
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Therefore, some members of the same group can have a property that another (M)ember lacks.
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If we define membership of a group by a property that a member (H)as but another member lacks, then we have (C)ontradicted ourselves.
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We cannot contradict ourselves.
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Therefore, we cannot define membership of a group by a property that a member has but another member lacks.
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Therefore, we must define membership of a group based on a property that all members have. The name of this property is an essential property.
N ⇿ G, P ⇿ ~(A & E), ~P, ∴ (A & E), ∴ M, H ⇾ C, ~C, ∴ ~H -
An essence is a group of essential properties.
For example, we live in a world where there are a myriad of entities some of which have properties that others lack. How are we to make sense of this morass without contradicting ourselves? Further, these entities change, acquiring new properties and losing others but somehow appearing to be the same thing. If we are to explain to someone else how to identify something without contradicting ourselves, then we cannot identify it by a property that it can have and not have but rather one property or a set of properties that it must have. The name for those properties that a thing must have are essential properties and we find those properties spelled out in the definition. Say, we defined dogs as that which has eyes. After all, dogs can have the property: “has eyes.” This belief would quickly be contradicted when we discovered other animals with eyes which were not dogs. We solve this problem by singling out either one property or a small set of properties that each member of the group must have.
