# Paradox of 'more quantity means greater satisfaction' in consumer behavior

I am trying to understand consumer behavior in microeconomics. Consider a market basket of food and clothing. Utility / Satisfaction of 200 gram food + 2 shirts is always supposed to be greater than that of 100 gram food + 1 shirt, because 'more is better'. So the 1st combination lies on an indifference curve that is outward with respect to the 2nd combination.

But, just in theory, if my basket consists of only 1 item (food). At some point more of food will be less of utility - I can't keep on eating more and more. In Krugman's book there is an example of a utility function that actually rises, plateaus and then starts dipping, which is intuitively right, but then violates 'more quantity is more satisfying'. In Pindyck's book this scenario is carefully avoided, and the discussion jumps straight into indifference curves.

It looks like an indifference curve is impossible without at least two items (since there is a question of marginal substitution also - how can one substitute with only 1 item?). But would it not be true that even with 2 items the utility function should rise, plateau and dip, and so, some indifference curves with more quantity of both items should lie inward of another one with less? (Think 2 items - burgers and soft drinks - I have 2 burgers with 2 bottles, then 3 + 3, 4 + 4, etc., .. at some point lets say 5 + 5, will be less satisfying, and so the 5 + 5 indifference curve will be below the 4 + 4 one. A diagram in Pindyck implies that 4 + 4 will always be on a shaded quadrant below the quadrant of 5 + 5 - this is non-intuitive.)

Could someone explain what appears to me like a paradox?

• How is 'more quantity means greater satisfaction' a paradox, in consumer behaviour or anywhere else? Sep 25 at 20:14 In that case utility function will have general properties that $$U'_x>0$$, $$U''_{xx}<0$$, $$U'_y>0$$ and $$U''_{yy}<0$$ where $$x$$ and $$y$$ are some composite goods such as let's $$x$$ could be basket of produced goods and services and $$y$$ basket of some natural goods such as air quality etc.