Why are the objects from and to separated (why not work directly with first and second)?

Separately highlighting the from and to objects instead of working directly with first and second is justified by several reasons:

1. Clarity and semantics — from and to explicitly reflect the direction or role of the object in the operation, whereas first and second are just ordinal labels.

2. Flexibility and extensibility — if the logic depends on the direction (e.g., conversion, copying, data transfer), using from and to simplifies understanding and modifying the code.

3. Error avoidance — working with first and second can easily lead to confusion about the order, which may cause bugs. Explicit names reduce this risk.

4. Support for clean code principles — the code becomes more readable and maintainable.

Example:

public void transferData(DataObject from, DataObject to) {
    // Clearly shows that data is copied from 'from' to 'to'
    to.setValue(from.getValue());
}

Unlike:

public void transferData(DataObject first, DataObject second) {
    // Not obvious who is the source and who is the recipient
    second.setValue(first.getValue());
}

Thus, highlighting from and to improves readability and reduces the likelihood of errors.