## We don’t know what we don’t know.

We can keep learning, and get closer to knowing everything, but we can never be certain that there’s nothing left to learn.

Mathematically, a tangent is an angle’s sine divided by its cosine. A graph of the tangent function starts at 0, increases to infinity, drops instantly to negative infinity, increases until it returns to 0, then starts all over again. A straight line touching the rim of a circle at only one point is also a tangent. All four sides of the blue squares in Professor Tangent’s logo are tangents to the inner green circle, a pictorial representation of the professor’s occasional tendency to "go off on a tangent". A "tan gent" is also what the cultured professor becomes after a few days of lounging on the beach.

## The tangent function

As the angle (represented by the X axis) approaches 90°, the value represented by the Y axis approaches infinity. This is called an asymptote. Just past 90°, there is another asymptote in the negative direction. What happens at exactly 90°? Like the concept of infinity, it’s not defined precisely. We can only really know what happens as we get close - and we can get very close. It’s kind of like filling pages with 9s - the number keeps getting bigger (and closer to infinity), but no amount of paper is sufficient to actually reach infinity. Learning is a similar process.

## Okum Taylor

A close friend of the professor, Okum Taylor lacks a rigorous academic background, but the professor respects Okum’s abundant common sense, practical analysis and ability to simplify seemingly complex issues.

## Who thinks up all this stuff?

Many people. Some of these ideas may be thousands of years old and are probably unattributable. Beyond that, why be concerned? If anything here isn’t reasonable, convince us and we’ll change it. If it is legitimate, crediting a particular individual won’t make it any truer, and could diminish the contributions of others who may be unknown. Think of it as stone soup for the soul.

If I have seen further, it is by standing upon the shoulders of giants.
Sir Isaac Newton

Many ideas grow better when transplanted into another mind than in the one where they sprang up.
Oliver Wendell Holmes

Learn from the mistakes of others - you can’t live long enough to make them all yourself.
Martin Vanbee

The secret to creativity is knowing how to hide your sources.

## How we attribute quotes

Attributing quotes can be particularly troublesome and unreliable. Often, there’s no practical way to trace the ultimate source, or to know what the exact words really were. We select quotes that are interesting, important, or clever on their own. If nothing else, an attribution means that we wish we could take the credit, but someone else thought of it first.