Probabilities

Thread originally posted on the Aeclectic Tarot Forum on 24 Aug 2001, and now archived in the Forum Library.

Kimon	24 Aug 2001
Hello, as I am not a gifted person in maths and maybe someone here is... Some years ago a friend calculated by whatever formula how many possible cards combinations are possible with 78 cards. Out came a truly monstruous number which I dont remember any more. Does someone know how you calculate this? Just for curiosity´s sake. Thanks, Kimon

raeanne	24 Aug 2001
If I remember my math correctly, the formula is 78 times 77 times 76 times 75 times 74 times 73 times. . . all the numbers, all the way down to 1. It is something like 1.132428 x 10^115. (Approximately 1 with 115 zeros after it.) Big number, indeed!

nexyjo	25 Aug 2001
it would depend on how many cards are in a reading too. luv and light, nexy

Kimon	25 Aug 2001
Hello, thanks for the formula; and yes, you are right, it would depend also from the cards in a spread; the formula says it for two cards I guess. Greetings and thanks again, Kimon

Talisman	25 Aug 2001
Good question Kimon. And thanks, raeanne, for working out the answer. Makes my head hurt to think about it. As someone said, a bazillion here, a bazillion there, pretty soon it adds up. So, with a number followed by 115 zeros, without factoring in all the number of cards in a spread as nexyjo suggests, and if each card represents a range of possibilities, why are reversed cards needed at all? I am neither for or agin reversed cards. With my ancient Aquarian deck, the book I had recommended reading reversed cards so I always did. With the Robin Wood deck, in her wonderful book she says why bother, so I don't use reversed cards. And I don't believe readings with the RW deck have any less depth than with the A deck. Still, with all those googleplex numbers, it should be amazing that cards so often repeat. But it isn't. Actually, in real life, it seems coincidences abound. In fiction if a writer uses coincidences to resolve plot problems it is unsatisfying and amatuerish, but in real life coincidences happen ALL the time. I'm sure there is a field of math that covers this, and raeanne could probably explain it. So, shuffle-mix-shuffle the cards and lay them out again, but don't be surprised if the same cards come up. Must be a message there, huh? Oh, how I wish I could really read that message. But in spite of those 115 zeros, the coincidence doesn't surprise me. Talisman Who counts on his fingers.

nexyjo	26 Aug 2001
i studied statistics in college. though i've forgotten as much as i remember. one thing i do remember is that it is statically probible that coincidences will happen, in the context of a random draw. it would be improbible that each card you pulled was evenly spaced in timing. it's much more probible that you get "clumps" of similar, or the same item in a set. luv and light, nexy

magnwa	26 Aug 2001
Interesting.. I never thought of reverses, since I don't use them. Let's look at a 10 card spread, allowing reversal's 156 * 154 * 152 * 150 * 148 * 146 * 144 * 142 * 140 * 138 (As each card pulled out uses one meaning, and eliminates the possibility for another meaning to show up.) 4.67 x 10^21 The number 467 with 19 zeroes after it :) *chuckles* Reversals aren't needed mathematically, but they can help, I suppse. I don't even wanna know how many possibilities exist if you use a 78 card spread.. Let's look at a 20 card one though.. That previous number * 136 * 134 * 132 * 130 * 128 * 126 * 124 * 122 * 120 *118 5.05 * 10^40. *smiles* Reversals add. That's 505 with 38 zeroes following it doggedly. Magnwa

purplelady	27 Aug 2001
math makes my head hurt! 8-) .

Jimilyn	01 Sep 2001
Quote: purplelady (28 Aug, 2001 03:39): math makes my head hurt! 8-) . Mine, too, purplelady! We don't have an emoticon showing the little smiley guy with an ice pack on his head. :p But that's what math does to me much of the time. ;) Maybe that's why I'm getting confused about my personality, soul, and shadow cards. Only I can do the math...but I've been told about 3 different ways to add up the numbers and 2 different ways to tell which is soul and personality. :D So maybe it's not always math that puts the ice pack on my smiley's head. LOL Jimilyn

The Probabilities thread was originally posted on 24 Aug 2001 in the Talking Tarot board, and is now archived in the Forum Library. Read the active threads in Talking Tarot, or read more archived threads.