Causation is not symmetrical for things and properties {causation relation}. If x causes y, then y cannot cause x. If x causes y, x properties are rarely y properties.
Things can always be near, or happen simultaneously with, other things {companionship relation}. This prevents the first thing from having some properties.
Correlation is symmetrical for things but not properties {correlation relation}. If x correlates with y, then y correlates with x. If x and y correlate, x properties are rarely y properties.
Identity is symmetrical for things and properties {identity relation}. If x is identical to y, then y is identical to x. If x and y are identical, all x properties are y properties, and all y properties are x properties {Leibniz's law}.
Objects related by symmetry can be congruent except for one asymmetry {incongruence relation}, such as left-right pairs and clockwise-counterclockwise pairs.
Opposites {opposites relation} have a property that can have two values, share most relations and property values, and presuppose each other.
Relations {physical relation} can use different objects and still be the same relation. Physical relations do not affect physical objects.
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Date Modified: 2022.0225