  To ensure progress in astronomy over the coming decades, the key questions
are "what facilities will we build, and when?" Toward this end, the Association
of Universities for Research in Astronomy (AURA) recently commissioned a study
on future space-based options for UV and optical astronomy. The resulting study
- "From Cosmic Birth to Living Earths" - concluded that a space telescope
equipped with a 12-meter class primary mirror would make fundamental advances
across virtually all of astrophysics, including finding and characterizing the
atmospheres of dozens of Earth-like planets. This ambitious telescope concept
is referred to as the High Definition Space Telescope (HDST). In a recent arXiv
white paper, Elvis (2015) critiqued a subset of the findings of the AURA study,
focusing on the detection and characterization of rocky exoplanets in the
habitable zone. In this response, we clarify these issues to confirm that HDST
would play a transformative role in the study of terrestrial worlds. Its
capabilities for studying exoplanets would be truly unique, even in 2035, and
would complement HDST's broad and deep range of exciting astrophysics.
