Theory and hypothesis are not interchangeable. Hypothesis precedes theory. Always. Had he said "theories" he would be saying something completely different. It's another stage of scientific process altogether. In order: Hypothesis, empirical observation, theory, demonstration, new theoretical stage or field.

The bizarre CS idea of using "plain English" as a propagandic thrust to infantilize complex scientific theory is suspect. Let's eschew the idea. "Plain English" is Orwellian dumbing down.

There is a general agreement which links ontogeny and phylogeny, details working memory, its relationship to the allocortex, and subsequent episodic memory. So the neural correlates have been worked out.

The working memory and episodic memory papers in the last few years have isolated the correlates, we a have a fairly empirical neurobiological description of memory function and process.

What we're lacking now are the molecular mechanisms.