  This article discusses the relationship between emergence and reductionism
from the perspective of a condensed matter physicist. Reductionism and
emergence play an intertwined role in the everyday life of the physicist, yet
we rarely stop to contemplate their relationship: indeed, the two are often
regarded as conflicting world-views of science. I argue that in practice, they
compliment one-another, forming an awkward alliance in a fashion envisioned by
the Renaissance scientist, Francis Bacon. Looking at the historical record in
classical and quantum physics, I discuss how emergence fits into a reductionist
view of nature. Often, a deep understanding of reductionist physics depends on
the understanding of its emergent consequences. Thus the concept of energy was
unknown to Newton, Leibnitz, Lagrange or Hamilton, because they did not
understand heat. Similarly, the understanding of the weak force awaited an
understanding of the Meissner effect in superconductivity. Emergence can thus
be likened to an encrypted consequence of reductionism. Taking examples from
current research, including topological insulators and strange metals, I show
that the convection between emergence and reductionism continues to provide a
powerful driver for frontier scientific research, linking the lab with the
cosmos.
