In Chapter 2 we learned how to skate the circuits. Now we can use those skills to work with digital representations.

# Binary Logic

In the world of binary there are only two states, false and true, zero and one. We represent everything else by combining these values together.

When we work with digital electronics, zero and one are represented by low and high current. The low signal is just above zero volts (~0.5V) and the high signal is conventionally 5 volts.

In binary logic, not only are there just two possible states, but all computation is broken down into binary operations, involving exactly two inputs.

To perform binary logic we use Boolean algebra, which has three essential operations: AND, OR, and NOT.

Imagine signaling with our hands, thumbs up or thumbs down. Thumbs up is equivalent to 1, logically true, electronically high. Thumbs down is equivalent to 0, logically false, electronically low.

These are the only two ways we can express ourselves in binary, nothing in-between.

The hand positions, thumbs up or thumbs down, will be the inputs to our binary logic.

Let’s say our friends go to the grocery store together…

We can think of the AND logic as a very simple form of voting.

In democratic societies, voting is how we choose political representation.

The artist Francis Alÿs once said, “sometimes doing something poetic can become political and sometimes doing something political can become poetic.”^{1}

The poetry of building a computer together becomes political when we begin choosing how to represent the world with zero and one.

The AND operation can also be represented as a Venn diagram, showing all the possible input configurations and colored only at the intersection of two circles, A and B.

We can also write AND as a truth table, like the one above. Truth tables enumerate each condition and the resulting output.

Based on what we learned from AND logic, can you guess what this next diagram represents?

Here every shape is colored *except* the intersecting region, telling us the output will be true except when both A and B are true. This is the exact opposite of AND, so we call this logic NAND for “NOT–AND.”

Binary lets us use other logics too, OR, NOR, XOR, XNOR. You can see the symbols for those gates and how they act in different situations in the chart below.

Let’s take a moment to look this over and convince ourselves the Venn diagrams match the truth tables.

NAND is special because combinations of NAND can turn any input into any output. NOR has the same property, which is why we call NAND and NOR *Universal Gates*, they let us make any logic we want!

Here’s how we can build a NAND circuit, like the ones on the left side of the diagram above, using the components we learned about in Chapter 2, transistors and resistors.

This circuit looks a lot like the negative logic circuit we made earlier, except we now have two NPN transistors next to one another.

When either of the two switches are turned off, current is unable to pass between the ground and +5V, so electricity will prefer to go through the LED to complete the circuit. Only when both inputs are switched on will current be allowed to flow directly to ground on the other side, bypassing the LED and displaying an output voltage of zero.

When building electronics, we use Boolean logic so often that it would be impractical to make a circuit like this every time, so we use abstractions of these components instead, integrated circuits (IC) which package each binary logic into a standard chip.

# Binary Numbers

By taking zero and one to mean *false* and *true*, we’re able to build a system of logic around that representation. But what if we now use zero and one to represent other numbers?

We’re used to thinking about *decimal* notation, which starts with 0 and counts up 1, 2, 3, 4, 5, 6, 7, 8, 9… but then something happens at 10, we carry into the next digit.

Another name for decimal is *base-ten*, because we increment 10 times before we say those numbers make up a group.

Binary numbers also start from 0, but since there are only two symbols, zero and one, every other count forms a group. So the number 2 in decimal is written 10, “one, zero.”

11 in the binary number system is equal to three in decimal, and 100 is equal to four. Every time we add 1 + 1, we carry that group into the next digit.

There’s something familiar here…

A number system is also a structure for repetition and abstraction.

# Absence Presence

Now we’re starting to see how all the bits of information stored in computers can be made of zero and one. We worked out how to represent logic and numbers digitally, what about language?

Written language is composed of symbols—letters, spaces, punctuation. If we want to represent the letter “A” with zero and one all we need to do is pick a number, say 01000001, and agree that any time we see 01000001, what we actually mean is “A.”

To do that, we make a big list of every character we might want to use and assign each a unique number. Then we share that list and refer to it whenever we communicate. The ASCII standard is one such list. That number, 01000001, is the 8-bit encoding for “A” in ASCII.

This seems simple enough. What’s not so easy is understanding how encoding language into binary affects how how we communicate. While thinking about this, I wrote a program to translate the alphabet into binary numbers and then draw the words with a pen plotter onto a piece of paper.^{2}

The numbers in this image represent the word “Absence” in ASCII. The first row is “A,” like above, the second row, 01100010, is “b,” the third row is “s,” and so on.

The word “Absence” comes from a poem I wrote during Occupy Wall Street, “Absence is Presence with Distance, Silence is Noise without Character.”

Occupy Wall Street meant something different to everyone. But for me, it was a moment of clarity. When I saw markets as cybernated circuits, that use computation and capital to feedback into themselves.

From the Greek “kybernetike,” for “governance,” cybernetics is the technology of feedback and control. The Financial Crisis revealed that we weren’t in control, it was capital that was governing us.

Occupy’s message was clear, but its form wasn’t. Transgression was fleeting, yet, for a moment I saw that a new kind of public space was possible.

I wrote the poem in Occupy’s final days, when the presence of protest was no longer allowed in Zuccotti Park.

On November 16th we were evicted by armed police and the park fenced at every corner. I rushed to my studio and made a robot from scrap wood and electronics, then brought it back to Zuccotti to protest in my place. A protest of one, in an empty park.

“Absence is Presence with Distance” is a message that uses the language of zero and one to bring the state of absence closer to the state of presence. If presence is *somewhere*, then distance is only an anticipation.

There’s a big difference between *something* and *nothing*, between *somewhere* and *nowhere*, between *sometime* and *never*. It is the difference of *being*.

What is it then, to be digital?

Alexander R. Galloway says “digital means the one divides into two.”^{3}
Not the digital computer—the digital being—the binary states of absence and presence.

If all we have is zero and one, we must cut one into two, so as to exist in-between.

If absence is 0, and presence is 1. The act of shortening the distance is the act of coming into presence, is the division we make, the cut, the scar, the imprint of our existence.

We are the scars of creation.^{4}

The creation of presence

—of being there

for one another.

# The Poetics of Presence

Zero and one can seem puzzling at first.

As we repeat and abstract it’s easy to get lost.

Like a Dan Graham installation, mazes of see-through mirrors and glass.

The path through is uncertain,

but then we change our perspective, *and…*

Underneath there’s simplicity. A logic that builds on itself—from a single transistor, to the scale of a city.

Clarity is the first step to poetry, but we’ll need something else.

*In the space of poetics, we find presence.*

We’re all different, so it’s hard finding closeness with others. Loneliness is everywhere, always. And those who’ve experienced nearness to death will know…

that feeling of emptiness.

The state of complete absence, forever near us,

so near we can’t see.

But the inevitability of death is something we all share. Our existence contingent on this finitude. Our time to live together and be present.

And the moment after death, in the time of mourning, we find one another’s presence.

In those moments of interdependence, zero stands for one, and one for zero. In those moments of presence, time and space are uncomputable, unphotographable, unarchivable—we feel the gap between thought and experience.

We find each other in a conversation which cannot be written or translated. “Dasein is becoming: it is not-yet. The structure is not that of life: The maturing fruit comes to completion, while Dasein is always in incompletion. Being by existing, Dasein is already its end, already its not-yet…”^{5}

I’d like to interpret Stiegler’s words into my own, “Presence is becoming, it is to be its not-yet. Presence is already its end, already its not yet.” That’s the uncomputability of presence—the poetics between zero and one.

Taeyoon Choi is an artist, educator, and activist based in New York and Seoul. His art practice involves performance, electronics, drawings, and installations that often form the basis for storytelling in public spaces. His projects were presented at the Whitney Museum of American Art and Los Angeles County Museum of Art. He co-founded the School for Poetic Computation where he continues to organize sessions and teach classes.

“Zero & One” is the third of seven chapters from *Handmade Computer*, a book written by Taeyoon Choi and edited by Sam Hart. Chapters will be released bi-weekly during the summer of 2017.

Alÿs, Francis. The Green Line, (2004).

^{↥}I used Plottr.js by Michael Simpson, who began working on the library at the School for Poetic Computation.

^{↥}Galloway, Alexander.

*Something About the Digital*. Chaos as Usual, (2011).^{↥}Levin, Janna.

*How the Universe Got Its Spots: Diary of a Finite Time in a Finite Space*. Princeton, NJ.: Princeton University Press, (2002).^{↥}Stiegler, Bernard.

*Technics and Time, 1 The Fault of Epimetheus*. Stanford, CA.: Stanford University Press, (1998).^{↥}