ABSTRACT
We discuss scientific realism in relation to modern cosmology, especially primordial cosmology. This is the cosmological investigation of the very early universe: where “very early” means, roughly, less than 10−11 seconds after the Big Bang (!). We first state our allegiance to scientific realism, and then take up two issues which illustrate that familiar philosophical threat to scientific realism, the under-determination of theory by data – on a cosmic scale.
The first issue concerns the difficulty of observationally probing the very early universe. The second issue concerns difficulties about confirming a cosmological theory that postulates a multiverse, that is, a set of domains (universes) each of whose inhabitants (if any) cannot directly observe or otherwise causally interact with other domains.
For these issues, it will be clear that much remains unsettled as regards both physics and philosophy. But we will maintain that these controversies do not threaten scientific realism.
