While talking about a period of time in human history, we talk about Ages: stone-age, bronze-age, and iron-age. Materials are used to categorize history, and not philosophy or religions. Going further, even silk, ceramics, papers were largely employed in human history, only the material in which human being achieved the most sophisticate technology, that were presentative to each age (?) Now, which material that our offspring will label our era?
Based on the previous criteria, there would be two candidates: either Silicon or Polymers. Silicon is considered due to its omnipresence in our life, which also represent a quasi-perfection in the fabrication method.
In Polymers, however, it is much more difficult to find a representative candidate, because of the variety of polymers, in microstructure as well as in properties.
Since the beginning of this century, there are hints that Polymers will be dominant material of the future. Metallic and semiconductor polymers have found places in electronics, while in biology they are becoming the choice of reference.
I work in Polymers, and this personal feeling clearly leans to Polymer, but time will say the final word.