When you start a company, you’re not working with a business plan. You’re working with a stack of guesses.
You guess that people want what you’re building. You guess they’ll pay for it. You guess they’ll switch from whatever they’re using now. You guess you can deliver it at a cost that makes sense. You guess they’ll find you, trust you, and come back.
These aren’t small details. They’re the whole foundation for your startup. It may sound logical, but when you internalize this as a startup founder, it completely changes your viewpoint on what to do and your perception of the risks you’re taking.
The Lens Shift
Most founders I meet talk about their ideas like they’re describing reality. “Parents will love this.” “Small businesses need this.” “People will definitely pay $10 a month.”
But that confidence is premature. Those statements are just theories…beliefs. And belief is fine for getting started, but it’s dangerous for making decisions.
But, when you see your startup as a bundle of guesses, everything shifts. You stop building like you know and start building like you’re learning. You stop defending your assumptions and start testing them. You become less attached to being right and more focused on finding out what’s actually true.
What You’re Really Building On
Think about Airbnb. Their entire business rested on one massive guess: people would sleep in a stranger’s home instead of a hotel. That wasn’t obvious. It wasn’t proven. It was a guess about human behavior that most people thought was wrong.
Or Uber. The foundational assumption was that people would get into a car with a stranger instead of calling a licensed cab. Again, not a fact. A guess.
The difference between those companies and the thousands that failed isn’t that they had better guesses. It’s that they knew they were guessing, and they tested those guesses before building everything else.
Not All Guesses Are Equal
Here’s where it gets practical. You can’t test everything at once, and not every assumption matters the same amount.
Some assumptions are like the foundation of a house. If you’re wrong, the whole thing collapses. “People will buy this or pay for this” is a foundation guess. No paying customers? No business.
Other assumptions are like the paint color on the house. If you’re wrong, you just change it. “Users will prefer the blue logo to green” is a paint color guess.
The trap is spending months on the paint color while ignoring the foundation.
I see founders obsess over features, pricing tiers, brand names, and color schemes before they’ve proven anyone actually wants what they’re building. They’re decorating a house on ground they haven’t tested.
Name What You’re Betting On
You can’t manage what you can’t see. So the first job isn’t testing. It’s naming.
Sit down and ask yourself: What has to be true for this idea to work?
Write each one down as a simple statement:
“Restaurants will pay to list on our platform”
“People will trust us with their financial data”
“We can deliver in under 30 minutes”
“Parents will order this weekly, not just once”
Now look at your list. Which ones are actually backed by evidence (data you can point to, behavior you’ve seen, patterns that are proven)? Those are facts.
Which ones are things you believe but haven’t confirmed? Those are your guesses.
The honest answer is usually: almost all of them are guesses.
That’s not a problem. That’s the normal starting point for every new thing. But once you can see them clearly, you can start testing them strategically.
Test the Foundation First
Once you’ve named your guesses, you need to test them.
Start with the assumptions that would kill your idea if they’re wrong. Test those before you build the full product. Before you quit your job. Before you spend months on things that only matter if the foundation holds.
This is where experiments come in. Put up a basic landing page to see if anyone tries to buy. Sell your product at a popup market to see if anyone wants it. Deliver your service once to see if the numbers actually work. You’re not trying to prove you’re right. You’re trying to find out what’s true.
Building Smarter
The risk in startup land isn’t that you’re making guesses. Every founder does. The risk is building on those guesses like they’re proven facts.
Because if you’re wrong (if the guess you built everything on turns out to be false) you’ve spent months or years and potentially a lot of money going in the wrong direction.
When you see your startup as a bundle of guesses, you build differently. You test earlier. You stay flexible longer. You catch the wrong assumptions before they become expensive mistakes.
And maybe most importantly: you stop defending what you hoped was true and start discovering what actually is.