What is a single-word synonym for "train of thought" that would cover exposition to someone else and internal philosophising?

I am seeking a single word to denote a character's train of connected thoughts, both when they are expounding a view or explaining something to another person and when they are analysing in their mind a set of circumstances or a problem.

Solution 1:

ideation

dictionary.com

the process of forming ideas or images.

brainwork

dictionary.com

1. work or effort consisting principally or largely of mental activity, thought, imagination, etc., as opposed to physical or manual work.
2. the effort of thought, reasoning, planning, or the like; ordered or directed thinking:

cerebration

Oxford dictionaries

The working of the brain; thinking.

ratiocination

Oxford learner's dictionaries

the process of thinking or arguing about something in a logical way

deliberation

Oxford learner's dictionaries

1. [uncountable, countable, usually plural] the process of carefully considering or discussing something

contemplation

Oxford dictionaries

1.1 Deep reflective thought

rumination

Oxford learner's dictionaries

1. the act of thinking deeply about something; deep thoughts about something

cogitation

dictionary.com

1. concerted thought or reflection; meditation; contemplation

2. the faculty of thinking

Solution 2:

Reasoning - The action of reason; esp. the process by which one judgement is deduced from another or others which are given. (OED)