What Is Entropy and Why Does It Matter for Tarot?
Pick up a physical tarot deck. Shuffle it. Feel the cards bending against each other, slipping past one another in ways you cannot precisely control. The oils on your fingertips, the micro-tremors in your muscles, the angle of each card as it falls -- every single variable is governed by physics so complex that no computer on Earth could predict the outcome. That shuffle is irreducibly unique. It has never happened before and will never happen again.
Now open a tarot app on your phone and tap "shuffle." What happens behind the screen is profoundly different -- and if you care about the integrity of a reading, that difference matters.
Entropy: The Universe's Measure of the Unknown
In physics, entropy is a measure of disorder -- or more precisely, a measure of how many possible microscopic arrangements could produce the state you observe. A cup of hot coffee has high entropy: the water molecules are careening in countless unpredictable directions. An ice crystal has lower entropy: its molecules are locked into an orderly lattice. The second law of thermodynamics tells us that entropy in a closed system always increases. The universe, left to its own devices, trends toward unpredictability.
This is not a flaw. It is the fundamental creative force of nature. Every snowflake, every coastline, every fingerprint exists because entropy ensures that physical processes never repeat themselves exactly. When you shuffle a tarot deck by hand, you are harnessing this force directly. Your hands are entropy engines.
Entropy is not chaos. It is the universe's guarantee that what happens next has never happened before.
How Computers Fake Randomness
Computers have a problem. They are, by design, deterministic machines. Give a processor the same input and it will produce the same output, every time, without exception. This is what makes them reliable. It is also what makes them fundamentally incapable of producing true randomness on their own.
When most software needs a "random" number, it uses what is called a pseudo-random number generator, or PRNG. A PRNG is a mathematical formula that takes a starting value -- called a seed -- and produces a long sequence of numbers that look random. They pass statistical tests. They appear unpredictable. But they are not. If you know the seed and the algorithm, you can reproduce every single number in the sequence, from the first to the billionth.
The most common PRNG you encounter on the web is Math.random(). In most browsers, this function uses an algorithm called xorshift128+, which generates numbers by performing bitwise operations on a 128-bit internal state. It is fast, efficient, and entirely predictable. Every "random" number it produces was already determined the moment the seed was set.
For video games, simulations, and A/B tests, this is perfectly fine. For tarot? It raises a question worth sitting with.
The Problem with Predictable Divination
Tarot has always been rooted in the idea that the shuffle matters. Whether you understand that metaphysically, psychologically, or simply as ritual, the act of shuffling is where the reading begins. The reader's hands, their energy, their intention -- these are not incidental to the process. They are the process.
If a digital shuffle is generated by a deterministic algorithm seeded by the system clock, then your reading was effectively decided by what millisecond you happened to tap the screen. Two people opening the same app at nearly the same moment could receive identical readings. The "shuffle" is an animation played over a predetermined outcome. It looks like randomness. It is a performance of randomness.
If you could rewind time and tap the button at the exact same millisecond, you would draw the exact same cards. That is the definition of deterministic -- and the opposite of what a shuffle is supposed to be.
This is not a theoretical concern. It is how virtually every tarot app on the market works today. And for many people, that is acceptable. But for those who believe the shuffle should mean something -- that the cards you draw should be genuinely unpredictable -- it is a gap that no amount of pretty animation can bridge.
Three Sources of Physical Entropy
Entropic Tarot takes a fundamentally different approach. Instead of generating numbers from an algorithm, it harvests real physical entropy from three sensors on your device, each capturing a different kind of unpredictability.
Microphone: Electromagnetic Noise
Your device's microphone does not just pick up sound. Even in a silent room, the analog-to-digital converter captures faint electromagnetic fluctuations -- thermal noise from the circuitry itself, interference from nearby electronics, subtle variations in voltage. These signals are genuinely random at the quantum level. Entropic Tarot samples this raw noise floor and extracts entropy from it, turning the hiss of your phone's own electronics into fuel for your shuffle.
Camera: Thermal Noise from Silicon
Your phone's camera sensor is made of silicon, and silicon is made of atoms that vibrate with thermal energy. Even with the lens cap on (or pointed at a dark surface), the CMOS sensor registers faint signals caused by electron excitations -- random thermal events at the atomic level. These manifest as the subtle grain you see in low-light photos. Entropic Tarot captures frames from the camera and harvests this noise, extracting randomness that originates in the physical behavior of matter itself.
Touch: Microsecond Timing Jitter
When you touch your screen, the timestamp of that event is recorded with microsecond precision. The exact moment your finger makes contact -- down to the millionth of a second -- is influenced by the speed of your neural impulses, the elasticity of your skin, the micro-vibrations of your hand. No two taps are ever identical at this resolution. Entropic Tarot captures the precise timing of your interactions and uses the jitter between them -- the tiny, unpredictable variations -- as a third source of entropy.
Mixing It All Together: SHA-256
Having three entropy sources is valuable, but raw sensor data can have biases -- a microphone might favor certain frequencies, a camera sensor might have a few hot pixels. To solve this, Entropic Tarot combines all three streams through SHA-256, the same cryptographic hash function that secures blockchain transactions and military communications.
SHA-256 takes any input -- no matter how biased or structured -- and produces a 256-bit output that is statistically indistinguishable from perfect randomness. Change a single bit of the input and the output changes completely and unpredictably. By feeding microphone noise, camera noise, and touch timing into SHA-256 together, the app produces a seed that is:
- Physically grounded -- derived from real-world phenomena, not formulas
- Unpredictable -- no algorithm can reproduce it, because no algorithm generated it
- Unique -- the combination of three independent sources at that exact moment will never recur
This seed then drives the card selection process, ensuring that each reading emerges from genuine physical unpredictability rather than computational theater.
Shuffling Until It Feels Right
There is a tradition in tarot that predates any app or algorithm. When you shuffle a physical deck, you shuffle until it feels right. There is no fixed number of shuffles. No timer. You shuffle until something -- intuition, instinct, a felt sense you may not have words for -- tells you to stop.
This practice has always been, in a sense, about entropy. The more you shuffle, the more disorder you introduce. The more your hands interact with the cards, the further the deck moves from any prior arrangement. You are not following a recipe. You are participating in a physical process that trends, inevitably, toward the unique and the unrepeatable.
The tarot tradition of shuffling until the cards "feel right" is an ancient intuition about entropy: the longer you engage with physical matter, the more irreversibly unique the outcome becomes.
Entropic Tarot was built to honor this. When the app harvests noise from your microphone, grain from your camera, and timing from your touch, it is doing digitally what your hands do physically -- gathering unpredictability from the real world and letting it shape the cards. The entropy is not simulated. It is not approximated. It is actual. It comes from the same physical universe that your hands move through when they shuffle a deck on a quiet evening.
The question was never whether digital tarot is "real." The question is whether the randomness behind it is. And the answer, for the first time, can be yes.