Science is about the external world: measurement, controlled experiment, data collection, empiricism. It tests hypotheses against the hard reality of repeatable experiments with objectively measurable results. Those who practice it are called scientists or empiricists.
Reason, by contrast, is internally generated. It’s building mental models of the world, starting with your internal sense for what is right and pure, from which further truths can be deduced. Those who practice reason are called rationalists.
Adam Wiggins of Heroku breaks down science vs. reason and how it affects business decisions in a startup -- and I was struck by how there are similarly very entrenched camps that are highly product (PG / YC-style / build something people want) oriented vs. highly metrics (Paypal mafia / Andrew Chen / Slide+Zynga) oriented.
When you build a product, you've got to have a worldview on what people want and what is useful and good. That's product sense. But once it is out in the world, you need to iterate and use empiricism to understand how your creation is doing. That's analytics.
As with science and reason, product and metrics are distinct things that happen to be extra valuable when used in conjunction.