I assume you are talking about Democritus. Even today, there is no satisfactory explanation for the question, "what is an electron?" We know how it behaves but we still don't know what it is composed of, modern quantum mechanics notwithstanding. But this is not the topic. The question was about whether time exists. Einstein's method was to treat time as another spatial dimension, constructing his model of the universe in four dimensions, so-called "spacetime"(t,x,y,z). This is absurd and has led to some of the greatest minds of the last century believing in time travel, wormholes and a host of other purely mathematical constructs. What is time?

"What has been has indeed objectively been and is no more. What will be, objectively is not and has not been (and, in fact, is not even fully determined, according to quantum indeterminacy). All physical systems ride the universal wave of becoming. Any awareness (ours or that of other intelligences) of past and future reflects the objective wave of becoming. There is no problem of "the arrow of time." There simply is no arrow of time, as if time could go one "way" rather than another. That metaphor is an unfortunate result of spatializing time. The picture of time as a line along which one might travel in one direction or the other is a conceptual disaster. Time is becoming. Becoming is change. The undoing of a change is also a change. There is no "unbecoming."

"Does the impossibility of motion in spacetime invalidate Einstein's relativity? The answer depends on whether one takes spacetime to be physically existent (as relativists do) or as an abstract, non-existent, mathematical construct for the historical mapping of measured events. If one chooses the former, one is obviously a crackpot or a fraud, or both. If one chooses the latter, then general relativity is to be seen as a mere math trick: the physical mechanism of gravity is still out there and it is incumbent upon physicists to find it."

"What about gravity, you say? Well, spacetime physicists understand doodley-squat about the true physical mechanism of gravity. It is dishonest and counterproductive for relativists to teach young people that, unlike Newton, they know what gravity is. All they have is a mathematical description of it and a hopelessly misleading and misinterpreted one at that. By now the reader should realize that there is no such thing as spacetime and that gravity does not have anything to do with the curvature of a physical spacetime. There is something else out there that causes bodies to fall, without a doubt, something physical, something material. Over the last century or so, relativists have steadfastly and sometimes deviously rejected any suggestion that space is not empty and that there is a need to invoke some sort of material substance or aether to explain phenomena like gravity. Given that spacetime is a fictitious math construct, it is obvious that it cannot possibly account for gravity. However, acknowledging one's ignorance is the first step toward acquiring knowledge. So all is not lost. Back to the drawing board!"

"People often talk about the passage of time. They say that time flows or changes. However, logically speaking, it is a fallacy that time changes. Clocks change, physical processes change but time is invariant. Why? Because, again, 'changing time' is self-referential. The truth is that nobody has ever observed time changing. We only use the changes in our clocks to derive unchanging time intervals. The nasty and shocking little truth is that time does not change, a million wormhole and time travel fanatics wearing their little Klingon and Ferengi outfits notwithstanding.

"The above may come as a shocking revelation to many but it is a logical fact, one that makes a lot of celebrated time travel and wormhole physicists look rather silly. "

http://www.rebelscience.org/Crackpots/notorious.htm