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Comment by function_seven | Hacker News Reader

This begs the question the video is trying to answer. Imagine you have no experience or knowledge of what electricity is or how it works. Then you learn the bare basics. You might have this same question, "how does it 'know' which path has the least resistance?"

The pepper demonstration in the video is a good analogy to show how the resistance information of every possible path (or, really, stub) is "back-propagated" to the branching point. No, it's not a perfect description of what is really going on, but I dare say there's no such thing. Just better and better models.

If I have a wire that connects from (+) to (-) on a battery, and a dozen wires that branch off of (-) and go nowhere, how does the current "know" not to waste time trying each of those stubs? This video explains that.

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> This begs the question the video is trying to answer. Imagine you have no experience or knowledge of what electricity is or how it works. Then you learn the bare basics. You might have this same question, "how does it 'know' which path has the least resistance?"

You're still saying "path of least resistance" though.

A very important part of the answer is that it doesn't find it. All paths carry electricity.

So "take all paths" isn't begging the question, it's correcting the question, and "weighted by resistance" isn't begging the question, it's giving a pretty easy answer to anyone that understands the concept of "resistance" in a non-electrical sense that some paths let things through more easily than others.

And if you have a bunch of stubs, the electricity does go onto them. It just gets stuck at the end.

It sounds like you missed the point of what parent was trying to say. As one of those people who was in the exact situation the parent mentioned, your concise and incrementally more correct explanation wouldn't have helped me when I had the same question.

It may not have helped you but it wasn't begging the question either.

Or in other words, the comment had multiple points and I chose to respond to one of them.

>but it wasn't begging the question either.

Yeah, I think you're correct here. I'll clarify what I meant:

The title statement is "How electrons find the path of least resistance", and what I replied to said, "They take all paths weighted by resistance".

The underlying question remains: how do the electrons "know" what the weights are? When a new charge carrier enters the maze, how does it "know" that "turning left" will be an easier trip than "turning right"? How do most of them end up taking the express lane?

I guess the original comment wasn't meant to answer this question, but rather rephrase it to be a more accurate question in the first place. I misread it as an answer.

I don't really look at it the same way, though.

From my point of view, finding the path of least resistance does require some kind of "knowing", but taking every path doesn't take some kind of "knowing".

The electrons just push. Like you can push something across a surface with varied friction. Or you can try to walk down paths with different amounts of obstructions. And when they get through faster, they make room for more faster.

Why resistance exists and varies is a valid question, but it's not one that everyone will have. Some people need that explanation, but some people just need "It takes every path with equal vigor."

So the original comment was an answer to the question. Not the answer everyone needs, but a valid answer for many people.

Also a nice comparison is how lightning does actually find a single path, because the current flow makes the air it touches more conductive in an aggressive feedback loop.

> The underlying question remains: how do the electrons "know" what the weights are? When a new charge carrier enters the maze, how does it "know" that "turning left" will be an easier trip than "turning right"? How do most of them end up taking the express lane?

Question: when you observe water flowing on a flat surface do you see the water droplets freely separating from each other all over the surface until it's kind of evenly distributed or do you find the droplets tend to kind of follow or stick to one another?

For example, imagine you have nice trickling stream of water and that stream comes near a droplet, does the droplet join the stream or does the stream miss the droplet?

Does the new "charge" in the maze join with an existing stream or is it starting with a neutral maze and has to find the exit again?

It doesn't need to know that it needs to turn left or right, it just needs to go with the lazier option which happens to be the less resistant one.

it doesn't know. it 'samples' or whatever inadequate word you wish to use.

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