Economics theory in textbooks is conducted on the basis of nice graphs. They are usually not given quantity graduation on the axes. Often a table of economic relations is used which are not based on actual measurements but imagined up to show a theoretical point. The supply ‘curve’ is an example. Often a nice straight line that sometimes intersects the origin of the graph and even occasionally indicates a quantity of supply when the price is zero. The graph shows a relation that the price is determined by a fixed amount plus a factor multiplied by the quantity of supply. Reverse engineering this, the total cost of production is based on the price multiplied by the quantity of production so it becomes the sum of the fixed amount multiplied by the quantity of supply and the production factor multiplied by the square of the quantity of supply. That the cost of supply depends on the square of the supply quantity seems nonsensical.
A different graph is presented in the chapters on marginal costing in competitive markets with a curve that is close to a parabola of average costs price against quantity. When I reverse engineer to get the total cost of production the first part of the downward part of the curve gives a cost curve close to reality with the cost being the sum of a fixed cost and a variable cost multiplied by the quantity of production. But then reverse engineering the rest of the upward trending curve gives a sharply rising variable cost. One graph I have just reverse engineered shows the variable cost rising to about eight times the initial variable cost. As the material resource and services cost part of the variable costs should not change, there is an exaggeration of the labour part of the variable costs. Economic textbooks depend on believing that the productivity of labour declines at scale but surely not by a factor over eight.
The cost structure of producers is something that a scientist could obtain but economists depend on assumptions rather than a scientific approach.
I have a thought that economics is more like a religion than a science.