It is controversial whether the mind is physically reducible or not. If the mind is physically reducible, it must share properties with the physical world. To find out how the mind can be characterized, an “additive property” is used to describe the mind. The additive property is shown where many causes result in one effect. The additive property is shown in the biological domain when the senses process received input. It is also shown in the intellectual activities of daily life. In the physical world, there is no cause without an effect. The additive property of events is not satisfied in physical domain. If the mind is physically reducible, the additive property of the mind should not be satisfied. Because the additive property is shown in the mind, the mind cannot be physically reduced in terms of relationships of cause and effects.