system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Binary. How are a bunch of 0s and 1s able to make everything I know and love?
gpt
At the lowest level (almost), binary logic runs due to the actions of transistors. Transistors in digital logic circuits are used mostly as switches. You want the transistors to be either all the way OFF (no current flow) or all the way ON (lots of current flow). And you can use the output of one transistor to control the input of other transistors, so you can construct a complicated circuit by wiring them up in certain ways.  

Using just a few transistors, you can build very simple logic circuits to implement binary digital logic (called "Boolean" logic after the guy who invented it). It turns out that you can build any digital logic function with a combination of just a few simple circuit types, such as AND/OR/NOT (you can actually do everything with just one, but no one really does that). By combining those simple circuits, more complicated circuits can be made (such as an adder, a multiplexer, etc.). You can use those circuits to make even more complicated ones. Like a CPU.  

It's like if you had a bunch of little Lego blocks, and you could use those to make larger Lego blocks, and you could then use those to make even larger Lego blocks, and so on.   

The different parts of the PC have different functions, with the CPU acting kind of as the main brain and control center. It gets program instructions and data sent from the hard disc to the memory and then to it, manipulates the data as dictated by the stream of instructions, and sends data out to where it is needed.  And that stream of instructions are computer programs (or an operating system, or a BIOS) that are just instructions encoded in binary form. They are also built up in a hierarchical manner, like building Legos with Legos.   Likewise, the communications between the chips in a PC (and between PCs via the internet) are also built up in layers, with simple things made into more complicated protocols, which are then made into more complicated communications.    
  
The programs do things to manipulate the input/output devices of the computer. For example, they will display an image on the computer screen, which is simply an area divided up into very small pixels, each made up of three colors, and each color assigned a brightness.  This is essentially an array of numbers, and computers are good at doing things with numbers. Other things can also be represented with numbers, such as sounds. Basically, if you can find a way to represent something as a number, you can make a computer manipulate it.
  
**TL;DR** - Legos.