How does the Time Traveler introduce his bold idea

The narrator recounts the explanation of two difficult ideas by a man he refers to as the Time Traveler (hereafter known as "TT") to an after-dinner group. The group includes a Psychologist, a Medical Man, a Provincial Mayor, and a few other men. The TT explains that Time adds a fourth dimension to the three dimensions of space. We overlook the fourth dimension because "our consciousness moves along it." He argues that Time, therefore, is a dimension of space. The Medical Man believes the difference between Space and Time is that one cannot move in Time and "get away from the present moment." The TT counters that we are always doing just that, "passing along the Time-Dimension with a uniform velocity."