> Your second sentence is sort-of true, but it seems to assume a lot and kinda rubs me the wrong way.

Sorry about that. I am just being direct. I don't know enough context about your idea to say, but it is what I consider a pattern.

Please do not take the below as personal criticism, my intent is genuinely to be helpful to you and others with a similar situation/mindset.

> There's plenty of demand to go around when I do cut through the noise, and plenty of customers have validated what we're doing verbally and more importantly with their pocketbooks.

"when I cut through the noise" is a slippery slope. It's not really practical for startups with limited resources to bet on. Warreb Buffet is famous for saying he doesn't look for 5-foot fences to jump over, he looks for 1-foot fences to step over. This type of situation is more of a 5-foot fence. It does not mean you won't be successful, just that your probability is lower from the market perspective.

> Do you believe that facade apps can test all business ideas?

This question is flawed. Nothing can test all aspects of an idea, and an experiment need only be designed to test the most important aspects of an idea. Landing pages can test value proposition, acquisition channels, pricing, and customers' willingness to pay (for all ideas).

> Or do you agree that there are some kinds of business ideas that you can't really test using a static app?

See my last point. You have decided your time is best spent on an idea where you believe your MVP requires significantly more investment than other ideas. You may be right or there may be a way to test it more cheaply that you haven't thought of. My point is that if you are right then you have signed up for a 5-foot fence. My concern is that people who say, "when I break through the noise" usually keep persevering without deciding on and committing to a failure criteria for this idea.

> Did Uber test their idea using an Invision mock-up?

I have to check. It was not a polished app or one built with significant time or resources.

> Can I tell if a video game will sell using a mock-up?

Technically, you can test if it will sell with a landing page and fake screenshots.

> Do you think Apple validated the market for the Pencil using mock-ups?

Apple has billions in cash and existing distribution, it is not a startup.

> Do you think Teller has a valid point that his magic tricks won't work in practice form, or do you think he's wrong?

I think it's irrelevant for startups.

> All that said, I am assuming that a "valid" business idea is one that has market potential but hasn't succeeded yet. If what you mean by "valid" is one that has succeeded, then I totally agree with you.

Technically, yes. Which is why worrying if an idea is valid is useless, one need only worry if it is invalid.

> From my perspective, there's a much larger gap between a valid idea and success than there is between an invalid idea and a valid one.

This might be the crux of the issue. There is an enormous gap between valid and invalid if you take the experimentation approach.

> Honestly, I don't really even know what an "invalid" idea is. There are plenty of bad ideas that make money, and plenty of good ones that don't, and it's extremely rare that the causes are clear enough to call the idea invalid.

Good and bad is subjective. If you set failure criteria, invalid is not.

> Success almost always has more to do with execution, timing, funding, and luck, than with the idea.

Let me get back to you on this one shortly.