It's a simple order of magnitude calculation. 2^256 is greater than one billion to the eighth power, times 100,000. There are probably several possible ways you could estimate how many different objects a person could distinguish between, but I think it's unlikely you'd come up with even a single billion.
> but I think it's unlikely you'd come up with even a single billion.
One billion is really really tiny though, let's just play a game :
- Unless you're colorblind, you can easily tell ten hues apart. Let's pick two colors, one with a saturated hue, and the other with a pastel one. That's 100 possibilities.
- I'm pretty sure you can easily recognize pictures of a hundred people you've met at some point in your life. Let's pick two of them, that's 10 thousand combinations.
- can you recognize ten different road signs? Ten country shapes ? Ten animals ? Ten fictional character? Ten books cover? Ten celebrities? Just pick three categories, and you've got a thousand combinations.
Now I'm pretty sure you can tell your grandma sitting under a vivid pink UK shape next to your 9th grade math teacher staring at Bruce Willis holding a giant light blue stop sign apart from any other imaginable combinations.
An untrained[1] human brain probably cannot distinguish between 2^256 items, but it's still able to do it for massive numbers.
[1]: but maybe it's possible with training: for instance, chess professionals might be able to do it.
