This is a question that needs to be asked way more often.
There's a lot of talk in the startup world about "ideas people" vs. "tech people". Here's an example post and at the end the author rightly notes that he could flip his whole argument on its head and it would still make sense. Ideas people and tech people both need each other equally.
I feel however that the discussions usually focus on the wrong things, as if to suggest that a startup basically has two challenges, (1) What to build and (2) How it's going to get built.
That's the easy part.
The difficult part is going to be (3) How to get people to use the damn thing. Startups don't live-or-die depending on how neat the idea is. They live-or-die depending on whether they can find or create a market for themselves. So often I hear terrible (or just plain non-existent) answers to the question "how are you going to get customers"…
If you're an ideas person or a business cofounder looking for a technical cofounder, you need to do your best to bring a solution to this piece of the puzzle. Don't even approach a potential technical cofounder without an answer to this.
Here's the kind of thing you want to be able to say:
I've had this idea for a while now. It's deeply connected to my current industry where I've reached senior level - but I'm now ready to strike out on my own. I've pre-sold the solution to 5 of my clients already and I have another 10 waiting in line for when we can scale things up a bit.
With the money from the 5 contracts I can pay us both a small salary which we can bump up when we sign up the other 10. I'm willing to offer up to 40% of the company to you if you do this with me
An idea and some code is called a project.
An idea, some code and a plan is a startup.