A startup is like a science experiment because its product design is a hypothesis about its market and its product is the experiment to test that hypothesis. And you the entrepreneur are the scientist conducting an experiment.
The difference is, if you control all of the other variables in an experiment, you can always predict the outcome after you've proven the hypothesis in a science experiment. However, market behaviors change over time and so the experiment can never control enough variables to be right 100% of the time. That's why I like the business world. Change is fun!
In a startup, most of the time you do not even know what the variables are that can affect the outcome; so you have to guess and hope for the best. The learning comes from examining the outcome and then discovering all the variables you never even knew existed - so you go back and change your hypothesis or product to deal with the new variables. And so it goes...