Why do some scientists not think interphase is a phase of mitosis?

Some scientists do not consider interphase a phase of mitosis because interphase is the stage of the cell cycle where the cell prepares for mitosis, rather than actively dividing. During interphase, the cell undergoes growth, DNA replication, and preparation for division, but it does not involve the processes of chromosome alignment, separation, or cytokinesis that characterize mitosis. Therefore, interphase is seen as a preparatory phase rather than a part of the actual mitotic process.