Indeed, since Isaac Newton James Maxwell was the first fundamental physicist and mathematician who successfully combined countless unrelated experiments, observations and mathematical models on electricity, optics and magnetism and synthesized them into a consistent theory. Although Maxwells theoretical work and interests extended far beyond electric and magnetic fields, and included color analysis, thermodynamics, kinetic theory, and metaphysics, essentially electromagnetism is considered as Maxwells greatest achievement and legacy.
Through his formulas, observations, experiments and deductions James Maxwell revealed that electromagnetic fields move through space as waves and at the speed of light. In December 1861, before the last two parts of his On Physical Lines of Force was published, Maxwell wrote to friend that I am trying to form an exact mathematical expression for all that is known about electro-magnetism without the aid of hypothesis (Harman, 113).
In 1864, he would publish his A dynamical Theory of the electromagnetic field in which he finally represented his mutual embrace of electricity and magnetism as fields varying in time. He announced his success to George Gabriel Stokes, secretary of the Royal Society, writing that he now had materials for calculating the velocity of transmission of a magnetic disturbance through air founded on experimental evidence without any hypothesis about the structure of the medium or any mechanical explanation of electricity or magnetism (Buchvvald, 20).
This was his electromagnetic theory of light, which depended on the introduction of a new concept, the displacement current, a mathematical representation of an electrical tension in a medium (Buchvvald, 32). If that medium could be known then a physical theory of the displacement current might have been feasible, but the fact that Maxwells displacement current could act across a vacuum presented a problem.
In fact, the physical interpretation of the concept of a displacement current would turn out to be a significant problem for late nineteenth century followers of Maxwell since it depended upon the structure of Maxwells mathematics and the hypothesis of the medium as the electromagnetic ether, without specification of the physical nature of that medium. This gap in Maxwellian electromagnetic theory was particularly troublesome for many physicists like Thomson who, in his Baltimore lectures in 1884, would remark that: if I can make a mechanical model of a thing I can understand it.
As long as I cannot make a mechanical model all the way through I cannot understand; and that is why I cannot get the [Maxwellian] electro-magnetic theory (cited in Smith and Wise, 464). James Clerk Maxwell has been widely acclaimed for his method, which untraditionally was not of a mathematical or mechanical nature, but of a philosophic one. Maxwell explained that, the chief philosophical value of physics is that it gives the mind something distinct to lay hold of, which if you dont, Nature at once tells you you are wrong (Campbell and Garnett,, 306).
Maxwells philosophical approach to physics has been highly influential on later generations of physicists, particularly Einstein. Back in 1856 during his Inaugural Address at Marishal College, Maxwell described in detail the basics of his scientific method. He affirmed the physics of extended bodies as integral and probably the central conception in the exact sciences. Maxwell divided natural science into two branches: the first, those which are rational, built upon the fundamental ideas of force and mass without any appeal to experimental measurements (Jones, 71).
This branch included the sciences of mechanics, and, though not strictly correctly, astronomy and rational elasticity theory. The other branch incorporated observational sciences, which we cannot completely explain, but we can mathematically define (Jones, 72). These included phenomenological elasticity theory, thermodynamics, optics, and electricity and magnetism. Therefore, for Maxwell, final moral responsibility of a scientist lay with the individual but only in submission to the truth of the greater order.
Maxwell looked for the possibility of a great development of the will, whereby, instead of being consciously free and really in subjection to unknown laws [attraction of surrounding things, subjectively capricious internal states], it becomes consciously acting by law and really free from the interference of unrecognised laws (Campbell and Garnett, 305). These laws of right action were ideal but they were also founded in the truth and unity of the sciences, which for Maxwell meant the material sciences.