How does tarot work?

Had a talk with an old friend about Tarot recently. She asked how I did it and I started with logistics,  a tarot deck,  78 cards (more than a playing card deck),  I always start with the same layout (the Celtic Cross) and do the readings, responding to how the cards fall, in what order.  

But how does it work? 

The body is made up of water and energy,  with a bit of calcium and thickener for the organs and bones.  What we know about the body is growing in leaps and bounds,  but what we know about mind and spirit is much more circumscribed.

I don't know how the energy of the body attracts some cards and repels others.  Because I do so many readings,  I see the magic of it all the time. Does it work because we both want it to?  I've read for real sceptics and had very accurate readings.   I gave her the example of the reading I did recently with the man drawing justice reversed and it turns out he was in the middle of a court case that was not going well.  How did he draw that card and not another?  I don't know that.  

But I do see it time and again.  People with money problems have their pentacles reversed,  people with pain in the hearts draw the three of swords. And equally importantly, people who are in good places relationship wise, don't draw the 3 of swords.  They draw the 2 of cups or the Lovers.  

I believe in psychic phenomena,  so I see evidence of it all the time.  It's hard to have a clear explanation,  but I say,  sometimes you sit next to someone on the bus,  someone you have no interaction with,  and you can see if they are happy or sad,  excited or bored.  The cards take it a step further,  happy about love,  bored with work,  or excited about work,  sad about past love. 

And that's what you go to a tarot reader to see - the pattern and how it is reflecting your life.