Newtonian physics treated space and time as absolute inertial reference frames. Space and time was independent of all that it embraced and in that sense, absolute. Space and time was isomorphic, and together with the particle theory of nature formed a mechanistic universe and static concepts that go along with it. Kant used Newtonian physics of space and time as intuitions. The sensorium (reference frame) was transferred from space and time itself (or even God) to the mind of the subject. Thus, the intellect imposes its laws upon nature and not nature upon the intellect. Kant believed our thought imposes Newtonian concepts on our experiences. Independent of experience our minds are organized to think about the world in the Newtonian framework. Scientific knowledge was considered a priori knowledge of synthetic truths.
This is what accounted for deductive methodology—using fixed premises and drawing one’s conclusions from these premises. Kant believed that one could not know the Ding an Sich by pure reason. The subject is limited to the fixed categories of the mind and one shapes the apprehensions through these categories. Kant used these space and time intuitions as necessary. It proved inept for scientists to follow Kant’s use of Newton’s ideas as permanent features of the intellectual landscape having based their philosophy on his model of the universe.
In 1865 James Clerk Maxwell had unified electricity and magnetism by developing his equations of electromagnetism. It was soon realized that these equations supported wave-like solutions in a region free of electrical charges or currents, otherwise known as vacuums. Later experiments identified light as having electromagnetic properties and Maxwell’s equations predicted that light waves should propagate at a finite speed c (about 300,000 km/s). With his Newtonian ideas of absolute space and time firmly entrenched, most physicists thought that this speed was correct only in one special frame, absolute rest, and it was thought that electromagnetic waves were supported by an unseen medium called the ether, which is at rest in this frame.