Since we start the day in one state (focused) and finish in another (free-associating, unfocused), the two must be connected. Over the day, focus declines–perhaps steadily, perhaps in a series of oscillations.
Which suggests that there is a continuum of mental states between highest focus and lowest. Your “focus level” is a large factor in determining your mode of thought (or of consciousness) at any moment. This spectrum must stretch from highest-focus thought (best for reasoning or analysis) downward into modes based more on experience or common sense than on abstract reasoning; down further to the relaxed, drifting thought that might accompany gazing out a window; down further to the uncontrolled free association that leads to dreaming and sleep–where the spectrum bottoms out.
Low focus means that your tendency (not necessarily your ability) to free-associate increases. A wide-awake person can free-associate if he tries; an exhausted person has to try hard not to free-associate. At the high end, you concentrate unless you try not to. At the low end, you free-associate unless you try not to.
Notice that the role of associative recollection–in which one thought or memory causes you to recall another–increases as you move down-spectrum. Reasoning works (theoretically) from first principles. But common sense depends on your recalling a familiar idea or technique, or a previous experience. When your mind drifts as you look out a window, one recollection leads to another, and to a third, and onward–but eventually you return to the task at hand. Once you reach the edge of sleep, though, free association goes unchecked. And when you dream, one character or scene transforms itself into another smoothly and illogically–just as one memory transforms itself into another in free association. Dreaming is free association “from the inside.”
At the high-focus end, you assemble your thought train as if you were assembling a comic strip or a storyboard. You can step back and “see” many thoughts at once. (To think analytically, you must have your premises, goal, and subgoals in mind.) At the high-focus end, you manipulate your thoughts as if they were objects; you control the train.
At the bottom, it’s just the opposite. You don’t control your thoughts. You say, “my mind is wandering,” as if you and your mind were separate, as if your thoughts were roaming around by themselves.
If at high focus you manipulate your thoughts “from the outside,” at low focus you step into each thought as if you were entering a room; you inhabit it.That’s what hallucination means. The opposite of high focus, where you control your thoughts, is hallucination–where your thoughts control you. They control your perceived environment and experiences; you “inhabit” each in turn. (We sometimes speak of “surrendering” to sleep; surrendering to your thoughts is the opposite of controlling them.)
At the high-focus end, your “I” is separate from your thought train, observing it critically and controlling it. At the low end, your “I” blends into it (or climbs aboard).
The cognitive continuum is, arguably, the single most important fact about thought. If we accept its existence, we can explain and can model (say, in software) the dynamics of thought. Thought styles change throughout the day as our focus level changes. (Focus levels depend, in turn, partly on personality and intelligence: some people are capable of higher focus; some are more comfortable in higher-focus states.)