Fallacy

5 Composition and Division
Related to faulty analogy is the fallacy of composition; this is to assume that what holds true for each member of a class standing alone will hold true for all members of the class taken together. Since a whole sometimes does and sometimes does not exhibit the characteristics of its parts, it is not possible to assume that parts and whole will share the same characteristics in any given case. Illustrations are easy to produce. Someone might argue that since each member of the Supreme Court possesses his own personal prejudices, the decisions of the Court as a whole are bound to be the product of these personal elements. In fact, the very reason for group decisions is that a pooling of knowledge makes for sounder judgment than any individual member of the group is apt to produce. Incidentally, the fallacy of composition sometimes turns on the ambiguity of "all." Often "all" means "each instance." Thus the sentence, "All residents of these pueblos are Pueblo Indians," translates into "Each person, if he's a resident of these pueblos, is a Pueblo Indian." But sometimes "all" provides a way of talking about a totality (or Gestalt) that cannot be taken as simply a sum of its parts. No one would suppose that when Caesar wrote, "All Gaul is divided into three parts," he meant "Every instance of Gaul is an instance of tripartite divisibility." Whether or not the word "all" actually occurs in reference to a totality, there is danger in assuming that what is true of the whole is true in the same way of each of the parts, and, conversely, that what is true of the parts is true of the whole.
EXAMPLE COMMENT
A lobbyist points out, "A tariff on meat will benefit the stockgrowers, a tariff on coal will benefit the coal miners, a tariff on toys will benefit the toy manufacturers, a tariff on any commodity will benefit the producers of that commodity. Therefore, a tariff on all commodities will benefit everybody who produces any commodity -- and that is the whole country in one way or another." Since producers are also consumers, tariffs on everything may well bring more total costs than total benefits. Also, multiplication of tariffs inspires retaliation and creates other complications which cut down international trade and threaten domestic production.
An economist writes, "Each individual will further his own economic interest to the best of his ability. The result is that all individuals together -- society as a whole -- thereby achieve the maximum possible economic advancement." This cardinal assumption of Adam Smith's laissez faire economics is nowhere maintained in pure form today. Experience has shown that while the efforts of individuals seeking their own welfare contribute to the economic advancement of society in some types of production, they lead to duplication and waste in other areas. Consider the result of unregulated, competitive exploitation of an oil field.

The fallacy of division lies in assuming that what holds true for all members of a class taken together is necessarily true for each alone. This assumption is the converse of composition. Of course, what is true of all is often true of each, but not necessarily so. For instance, a general may strive to preserve the fighting efficiency of his army as a whole by giving orders which will result in the fighting efficiency of some units being destroyed. Less melancholy examples can easily be adduced.
EXAMPLE COMMENT
A city alderman proposes, "The City revenues have fallen off. I propose a 20 per cent across-the-board cut for all City Departments. We'll just have to get along with four-fifths of the service we've been used to." It is incorrect to assume that a 20 per cent budget cut will result in services differing only proportionally from the previous standard. Possibly reduced financial support will result in proportionate reduction of service in some departments, other activities may become unfeasible, and still others may not be noticeably affected. Further, the effects may be qualitative as well as quantitative. Street sweeping may be quantitatively reduced, while the City Engineer may quit and a competent replacement be unobtainable.
A famous lecturer says, "The credence given to Marx's economic interpretation of history is extraordinary. Why, Marx's own life denies his theory. Born the son of a lawyer with a comfortable place assured to him for the asking, still he chose the hard and penniless life of a political exile. If economic motivation had so little appeal for Marx himself, how could he believe all history to be determined by the economic motivations of mankind?" The lecturer's observation is thought provoking. Marx's own life does indeed provide a striking instance of a man whose primary motivations were non-economic. Even if Marx's point is right that all society organizes itself along the class lines of economic interest, it would be an instance of the fallacy of division to suppose that what is true of all taken together, need be true of each individual. Economic motivations might be a least common denominator sufficient to determine class interests even though no one person was primarily motivated by them.

EXAMPLE	COMMENT
A lobbyist points out, "A tariff on meat will benefit the stockgrowers, a tariff on coal will benefit the coal miners, a tariff on toys will benefit the toy manufacturers, a tariff on any commodity will benefit the producers of that commodity. Therefore, a tariff on all commodities will benefit everybody who produces any commodity -- and that is the whole country in one way or another."	Since producers are also consumers, tariffs on everything may well bring more total costs than total benefits. Also, multiplication of tariffs inspires retaliation and creates other complications which cut down international trade and threaten domestic production.
An economist writes, "Each individual will further his own economic interest to the best of his ability. The result is that all individuals together -- society as a whole -- thereby achieve the maximum possible economic advancement."	This cardinal assumption of Adam Smith's laissez faire economics is nowhere maintained in pure form today. Experience has shown that while the efforts of individuals seeking their own welfare contribute to the economic advancement of society in some types of production, they lead to duplication and waste in other areas. Consider the result of unregulated, competitive exploitation of an oil field.

EXAMPLE	COMMENT
A city alderman proposes, "The City revenues have fallen off. I propose a 20 per cent across-the-board cut for all City Departments. We'll just have to get along with four-fifths of the service we've been used to."	It is incorrect to assume that a 20 per cent budget cut will result in services differing only proportionally from the previous standard. Possibly reduced financial support will result in proportionate reduction of service in some departments, other activities may become unfeasible, and still others may not be noticeably affected. Further, the effects may be qualitative as well as quantitative. Street sweeping may be quantitatively reduced, while the City Engineer may quit and a competent replacement be unobtainable.
A famous lecturer says, "The credence given to Marx's economic interpretation of history is extraordinary. Why, Marx's own life denies his theory. Born the son of a lawyer with a comfortable place assured to him for the asking, still he chose the hard and penniless life of a political exile. If economic motivation had so little appeal for Marx himself, how could he believe all history to be determined by the economic motivations of mankind?"	The lecturer's observation is thought provoking. Marx's own life does indeed provide a striking instance of a man whose primary motivations were non-economic. Even if Marx's point is right that all society organizes itself along the class lines of economic interest, it would be an instance of the fallacy of division to suppose that what is true of all taken together, need be true of each individual. Economic motivations might be a least common denominator sufficient to determine class interests even though no one person was primarily motivated by them.