I think that the tarot Fool was likewise intended to be the first and lowest card in an ordered series. Given this structure, it remains to develop interpretations for each of the triads, explaining what dualism is being represented and how the third card resolves it and leads to the next higher triad. This is necessarily a speculative exercise. My own tentative interpretations follow. Although the basic triadic structure may have been given the deck by its designers, these specific interpretations are admittedly modern and personal.
Links connect to essays that explore the individual triads in greater detail.
Fool, Juggler, and Papess constitute the Physical Triad . Here the issue is one's relation to the physical environment. The Fool is the wretch, the idiot, a victim of the natural world, subject to the elements. The Juggler is the artisan and also the charlatan and thief, who works with his hands and thus dominates the physical world. The nun may also devote herself to charitable work, thus opening the next triad, that of society.