Choose 7 tarot cards
The number seven has a long history in symbolism: the seven planets of classical astrology, seven as a combination of three and four, themselves archetypal numbers, seven pillars of wisdom, the seven lower stations of the Tree of Life, seven openings in the human head, seven chakras, and of course, seven days in the week.
One particular aspect of seven relates it directly to the Tarot. The Greek letter pi stands for a ratio that exists in all circles between the circumference and the diameter. No matter how large or small the circle, the two will always work out to the same fraction, 22/7. And the Major Arcana with the Fool comes to twenty-two, just as without the Fool it reduces to seven. Also, twenty-two times seven equals one hundred and fifty-four (154 adds up to ten, linking it to the Wheel), and one hundred and fifty-four divided by two, for the two Arcana, comes to seventy-seven, the entire Tarot with the Fool again set aside.
He best reasons for the division into three groups lie within the Major Arcana itself. First, consider the picture symbolism. Look at the first card in each line. The Magician and Strength are both obviously cards of power, but so is the Devil. The Magician and Strength are linked by the infinity sign above their heads, while the Devil bears a reversed pentacle. If you look at the Devil’s posture, one arm up, one arm down, you will see the picture is in some ways a parody of the Magician, with the torch pointing down instead of the wand pointing up. In some decks card 15 carries the title of ‘Black Magician’. (In many decks Justice, not Strength is number 8. If you look at the posture of the figure injustice you will see an even closer resemblance to the Magician and the Devil.) The same kind of vertical correspondences apply all the way through the three lines.