These fallacies occur because the author mistakenly assumes that the whole is nothing more than the sum of its parts. However, things joined together may have different properties as a whole than any of them do separately. The following fallacies are category errors:
Because the parts of a whole have a certain property, it is argued that the whole has that property. That whole may be either an object composed of different parts, or it may be a collection or set of individual members.
Examples: (i) The brick wall is six feet tall. Thus, the bricks in the wall are six feet tall. (ii) Germany is a militant country. Thus, each German is militant. (iii) Conventional bombs did more damage in W.W. II than nuclear bombs. Thus, a conventional bomb is more dangerous than a nuclear bomb. (From Copi, p. 118)
Proof: Show that the properties in question are the properties of the whole, and not of each part or member or the whole. If necessary, describe the parts to show that they could not have the properties of the whole.
Because the whole has a certain property, it is argued that the parts have that property. The whole in question may be either a whole object or a collection or set of individual members.
Examples: (i) Each brick is three inches high, thus, the brick wall is three inches high. (ii) Because the brain is capable of consciousness, each neural cell in the brain must be capable of consciousness.
Proof: Show that the properties in question are the properties of the parts, and not of the whole. If necessary, describe the parts to show that they could not have the properties of the whole.