D.1. The Limitations of Economic Laws: The laws of economics can only be applied to the study of behaviour, given the set of means and ends. The laws of economics do not and cannot explain the given means and ends themselves. (From 1.2.1).
E.1. From 1.2.1 we know it is out of scope to discuss why someone has altruistic ends, or selfish, why someone has a certain set of means. Not only so, it would be irrational to try to apply the conclusion of the premises to the premises. The premises being the given ends and the given means, and the conclusion being the Laws.
The 'If X is Y, and Y is Z, then X is Z' is a logically valid argument, and now to try to explain X is Y or Y is Z using X is Z is nothing but a futile endeavour, something logicians are not interested in doing. Hence, it is the limitation of Laws of Economics that they, being deductions, cannot explain the changes in given data, although they always need, as inputs, the changes in data but neither they need to nor they can explain why these changes exist.
Reference: Chapter 04 of Robbins, L. (2007). An essay on the nature and significance of economic science.