One aspect of rationality is acting optimally (reasonably) on given data. In startups, you often need to act on little data, because when you wait for perfect information, the opportunity is gone. Unknowns can still be handled rationally, but need to be treated probabilistically. From this point of view, I really like the Lean Startup method, because it provides a framework to addressing the unknowns: lay out your plan, identify the greatest unknown, test it efficiently, rinse and repeat.
One aspect of rationality is acting optimally (reasonably) on given data. In startups, you often need to act on little data, because when you wait for perfect information, the opportunity is gone. Unknowns can still be handled rationally, but need to be treated probabilistically. From this point of view, I really like the Lean Startup method, because it provides a framework to addressing the unknowns: lay out your plan, identify the greatest unknown, test it efficiently, rinse and repeat.
Re: biases and startups: