Thoughts exist within a world of references and intentions. Content analysis of “wandering” thoughts has shown that such “stimulus-independent” thoughts are largely goal-directed and future oriented (Baird et al, 2011). Thoughts can be conversational and goal-directed at the same time. Imaginary conversations are like rehearsals; we silently speak to ourselves when planning. Even when we are rehashing past conversations, what may start as an act of memory often becomes elaborated, with what we shoulda, coulda, woulda said, if only we had thought of it at the time. This is one way the social animal prepares for future interactions.
Benjamin Baird , Jonathan Smallwood, and Jonathan W. Schooler (2011) Back to the future: Autobiographical planning and the functionality of mind-wandering. Consciousness and Cognition Volume 20, Issue 4, 604–1611