It seems to be popular in Europe to read with only the 22 trump cards and leave the pip and court cards aside. This is surely a pre-20th-Century form of cartomancy that antedates the lofty assumptions of Jungian thought and its psychological archetypes. I’m not familiar enough with Joseph Campbell to say so conclusively, but my suspicions are that his approach to the “Hero’s Quest” (our “Fool’s Journey”) was more anthropological and scholarly than supportive of the tarot’s worldview. The historical archetypes portrayed in the early trumps were culturally and religiously Medieval in origin and embodied aspects of life that were familiar to most people of the time, if only from the festival processions that featured mock-ups of the cast of characters similar to parade floats (see Cherry Gilchrist’s Tarot Triumphs). The pip and court cards were used for “trick-taking” card games as well as for gambling, and the introduction of the trumps at a later date added another dimension to the games in that those higher-ranking cards in a player’s hand could “trump” (or beat) the lesser cards held by other players, thus taking tricks (and probably coin) away from them during play. Divination was apparently an outgrowth of that more commonplace usage sometime in the 15th Century.
In the modern 78-card tarot deck, the trumps (aka Major Arcana) are sometimes considered to be a fifth “suit” apart from the familiar four of Wands, Cups, Swords and Coins (or Pentacles). Thanks to the co-opting of Jung’s and Campbell’s ideas, they are felt to be of greater importance than the other 56 cards in the deck, representing the likelihood of major events or significant developments when they appear in a reading. I liken them to typing in ALL CAPITAL LETTERS, which comes across as shouting when done in text communication; the more trump cards that show up in a spread the more clamorous the conversation becomes (and on rare occasions the ruckus is even justified). I found it interesting when talking to European readers that their tendency is not to accord the trump cards unique qualities that are vastly superior to those of the rest of the deck, such that when reading with a trumps-only pack the bar is set no higher when it comes to expectations for something momentous to happen.
Coming from a background in late-20th-Century divination, one must learn to modulate the influence of trump cards such that they speak more directly to ordinary circumstances. This is easier said than done since so few of them have counterparts in today’s culture. When was the last time you saw an Emperor? We must fall back on the less exalted symbolism: the Emperor can represent a father figure or the need to accept responsibility of some kind. In over four decades of practice I’ve found that trump cards very seldom represent earthshaking events anyway, despite their reputation, so I’m perfectly content digging out the less consequential meanings and using those in my interpretation as a starting point. At most, I consider them to show the broader “lay of the land” or background theme of a reading within which mundane events take place. There are also spreads where I leave them out of the deck entirely when examining routine, day-to-day circumstances.