73.      
　　In this argument the author reasons that a sequel to a popular movie will be profitable because the original movie was profitable and because books based on the characters of the movie are consistently bestsellers. This argument is unconvincing for several reasons.

      In the first place, a great deal of empirical evidence shows that sequels are often not as profitable as the original movie. For example, none of the "Superman" movie sequels even approached the success of the original movie. Accordingly, the mere¹ fact that the first movie was successful does not guarantee that movies based upon it will also be profitable.

      In the second place, a movie's financial success is a function of many elements in addition to well-liked characters. Admittedly, the fact that the books based on the characters of the original film are bestsellers bodes² well for the movie's commercial prospects³. However, unless the original cast and production team are involved in making the sequel, there is a good chance it will not be financially successful.

      Finally, another important element in creating a successful movie is the script. The transformation⁴ of a popular book into a popular movie script is a difficult process. Examples of best-selling books that were not made into successful movies are
commonplace. Obviously, the success of the sequel that Vista⁵ is planning will depend in great part on the screenwriter's ability to capture the elements of the story that make the books popular. Since the difficulties inherent in this process make it hard to predict whether the result will be a success or a failure, the conclusion that the sequel will be profitable is presumptuous⁶.

      In conclusion this is an unconvincing argument. To strengthen the argument, it would be necessary to provide assurances that the original cast and production team will be involved in the project and that the script will capture and develop the particular elements responsible for the books' popularity.

74.       
　　The conclusion of this letter is that consumers are not truly benefiting from advances in agricultural technology. The author concedes that, on the average, consumers are spending a decreasing proportion of their income on food. But the author contends that this would happen without advances in agricultural technology. The author reasons that demand for food does not rise in proportion with real income, so as real income rises, consumers will spend a decreasing portion of their income on food. This argument turns on a number of dubious⁷ assumptions.

      First of all, while asserting that real incomes are rising, the author provides no evidence to support this assertion; moreover, it might be false. Even if salaries and wages go up, this fact may not indicate that real income has increased proportionally. Real income takes into account any effect inflation might have or, the relative value of the dollar. It is possible that, when salaries and wages are adjusted for inflation, what appear to be increases in real income are actually decreases.

      In addition, the author assumes that increases in real income explain why, on the average, consumers are now spending a decreasing proportion of their income on food. But no evidence is provided to show that this explanation is correct. Moreover, the author fails to consider and rule out other factors that might account for proportional decreases in spending or food.

      Finally, the entire argument turns on the assumption that benefits to consumers from advances in agricultural technology are all economic ones—specifically, ones reflected in food prices. The author ignores other likely benefits of agricultural technology that affect food prices only indirectly⁸ or not at all. Such likely benefits include increased quality of food as it reaches the market and greater availability of basic food items. Moreover, the author cannot adequately assess the benefits of agricultural technology solely⁹ on the basis of current food prices because those prices are a function of more than just the technology that brings the food to market.

      In conclusion, this letter has provided little support for the claim that consumers are not really benefiting from advances in agricultural technology. A stronger argument would account for the benefits of technology other than the current price of food, and would account for other factors that affect food prices. To better evaluate the argument, we would need more information about whether real incomes are actually rising and whether this alone explains why consumers now spend a proportionately smaller amount of income on food.