How Can I Know Anything?

In this blog, I plan on focusing on the complex phenomena that are revealed through data science, but before I can investigating phenomena, there's a fundamental philosophical question I have to answer before I can answer any others:
How can I **know** anything? How can I be sure that an explanation is correct or a statement is true? 
Or, put less philosophically: How can I be sure that I'm not about to embarass myself and waste my time by being confidently wrong?

Philosophically, it's very difficult to know anything for a certainty. Philosophical skepticism holds that there's always the posibility that an unknown unknown is deceiving us, so it's impossible to be certain and someone could always poke a potential hole in any theory. Yet from our lived experiences, it's obvious that we know things. We know that we won't fall through the floor when we get out of bed, so clearly philosophical certainty isn't a very useful way to understand the world. Evolution has provided a much more pragmatic way to gain knowledge, and we start using it at birth.

When a baby keeps dropping things from their highchair, they're demonstrating my favorite answer to that question. We aren't born with knowledge of gravity or object permenance, so when that baby first discovers that objects fall downward when pushed off the ledge, they observe something interesting. The baby doesn't have a theory to explain the observations, but by collecting a lot of observations, they develop intuition. Their intuition improves with new observations (eg. both my red and blue sippy cups fell down when I let go of it), and they can make predictions (eg. my green sippy cup will fall down when I let go of it). Sometimes, we encounter unexpected observations (eg. the balloon went up when I let go of it) that force us to refine our intuition (eg. sippy cups go down and balloons can go up).

We use this same learning pattern through our entire lives; when we recognize a familiar scenario, we can use our prior experiences to make predictions, and if we recognized all the important aspects of the scenario, we can safely assume that our prediction will be correct. Stated more directly, we assume that reality is consistent. This is the fundamental assumption behind data science, and as long as reality remains consistent, we'll be able to predict the future if we can recognize the important parts of the present and find relevant observations from the past.