The late Sidney Coleman. Alan Guth and Andrei Linde, fathers of inflationary cosmology, at the Shelter Island II physics conference in 1983. My brother and I videotaped it, and I interviewed participants, for the American Institute of Physics archives.
The idea was only about three years old then; it's taken another 31 years to get the first really compelling observational evidence. These theorists would be the first to acknowledge the work of many others in (1) teasing testable predictions from the theory, and (2) setting up observations (in Antarctica, with an infrared sensor far colder than the landscape) to test one of those predictions.
Some answers are well worth waiting for.