I have two purposes in mind writing this blog post:
- Bring to your attention a new Santa Fe Institute paper on technological progress. I consider it quite a remarkable paper.
- Provide guidance as to applying the findings reported in this paper.
Bela Nagy et al have recently published a working paper entitled Statistical Basis for Predicting Technological Progress. Numerous intriguing observations are made in this paper, including the following comparison between Moore’s Law and Wright’s law:
We discover a previously unobserved regularity that production tends to increase exponentially. A combination of exponential decrease in cost and an exponential increase in production would make Moore’s law and Wright’s law indistinguishable, as originally pointed out by Sahal. We show for the first time that these regularities are observed in data to such a degree that the performance of these two laws is nearly tied.
No doubt, quite a remarkable discovery and conclusion. “Time is the teacher” (i.e. Moore’s law) is for some purposes as good a predictor as “We learn by doing” (i.e. Wright’s law). The fact that Wright’s law takes into account (whereas Moore’s law does not) the number of units produced during the period of time under consideration does not really matter.
The two laws IMHO are indeed indistinguishable not in a broad sense but in quite a narrow sense. The figure of merit used for measuring technological progress in this paper is ”inflation adjusted cost of one ‘unit’”. While this choice has various pragmatic merits such as straightforward aggregation of data across different kinds of technologies, it does not capture the performance “dimension” of a technology. For example, this figure of merit can’t be used to predict future performance of a computer system that is implemented using a certain technology. Technological progress over time, no doubt, will lead to improved performance of the computer system once it is re-implemented using the later generation of this technology. But, the results reported in the paper are not applicable to making such predictions.
In summary, the paper validates the explanation of Wright’s law in terms of Moore’s law that had originally been proposed by Sahal in A Theory of Progress Functions. This validation applies to cost as the figure of merit. It does not apply to the performance “dimension” of technology.
 The authors describe the two laws in the context of the paper as follows: “Moore’s law here refers to the generalized statement that the cost of a given technology decreases exponentially with time. Moore’s law postulates that technological progress is inexorable, i.e. it depends on time rather than controllable factors such as research and development… Wright’s law, in contrast, postulates that cost decreases at a rate that depends on cumulative production…”