Maybe a simple picture from object oriented programming will help.
The top box is the parent class (or set), the lower boxes are sub-classes.
The bottom boxes inherit all of the properties of the parent, but have unique attributes of their own. They share all of the properties of the parent with each other.
The sub class on the left has a property the one on the right does not and vice versa. The parent class has neither of the sub-classes unique properties.
In the replication example, the parent has replication as an property. One sub-class, biological has replicating replicators as a property. Another sub-class, inanimate objects, has manufacturing replication as a property. Yet they both share all of the parent's properties and maintain their own unique properties.
Why is this difficult to grasp? Seems fundamentally obvious.
![[Image: class-inheritance.jpg]](https://images.weserv.nl/?url=service-architecture.static-barryandassociates.com%2Fimages%2Fdatabase%2Fclass-inheritance.jpg)
The top box is the parent class (or set), the lower boxes are sub-classes.
The bottom boxes inherit all of the properties of the parent, but have unique attributes of their own. They share all of the properties of the parent with each other.
The sub class on the left has a property the one on the right does not and vice versa. The parent class has neither of the sub-classes unique properties.
In the replication example, the parent has replication as an property. One sub-class, biological has replicating replicators as a property. Another sub-class, inanimate objects, has manufacturing replication as a property. Yet they both share all of the parent's properties and maintain their own unique properties.
Why is this difficult to grasp? Seems fundamentally obvious.
