Everything Is a Number
The three assumptions are on the table. From here on, this course stops assuming and starts deriving — and the first derivation is one short step with continent-sized consequences. It answers, in three lines, how photographs, symphonies and novels fit into a machine that stores only numbers.
Start with the question
Your phone holds your photos, your voice messages, this very text. But the memory lesson was categorical: cells hold numbers, and nothing else exists in memory. So where, physically, is the photo?
Watch the derivation — the first in the course, and deliberately the simplest:
1. Whatever is in the machine is in memory cells (there is nowhere else).
2. A memory cell can hold only a number.
3. Therefore, whatever is in the machine is stored as numbers. No exceptions are possible — the conclusion follows from the premises, not from observation.
The photo is numbers. The voice is numbers. This text is numbers. Not "represented by numbers somewhere deep down as a technicality" — numbers are the only form of existence anything has inside the machine.
What this means, item by item
| Thing | Its numeric existence (previewed here, derived properly in coming lessons) |
|---|---|
| Text | Each character is a number in a correspondence table; a text is a run of such numbers |
| Image | A grid of points, each point's brightness and color written as numbers |
| Sound | Air pressure measured thousands of times a second; each measurement is a number |
| Table / database | Numbers arranged under an agreed layout |
| The program itself | Also numbers — and this row of the table is so consequential it gets an entire lesson of its own very soon |