corresponding retarded electric and magnetic fields. This conventional procedure is logically well-structured and then one can conclude that if Maxwell’s equations are postulated from the beginning then one can derive the retarded potentials and hence their corresponding fields. End of the story.

On the other hand, the reverse procedure starting with the retarded potentials and ending with Maxwell’s equations does not seem to be simple at first sight. Suppose that by some means (which of course does not involve the Maxwell equations) we have found the retarded potentials (5). Differentiating these potentials one obtains their wave equations (8) and equation (6). Combining (6) and (8) one infers equations (10) and (11) which are then identified with the inhomogeneous Maxwell’s equations whenever the electric and magnetic fields are defined as (12). In the final step, one uses these definitions of fields to obtain the homogeneous Maxwell’s equations. This reversed procedure is conceptual and pedagogically significative as long as one can convincingly justify the existence of the retarded potentials without explicitly appealing to Maxwell’s equations. This is the most difficult problem to solve.

But there is a conceptual disadvantage in the traditional procedure. If one *postulates* Maxwell’s equations from the beginning then 