The Hi, I'm Peter Adamson, and you're listening to the History of Philosophy Podcast, brought to you with the support of the philosophy department at King's College London and the LMU in Munich, online at

W.W. History of Philosophy.net. Today's episode, seeing is believing, Nicholas of Otakort's

skeptical challenge. Is having knowledge more like being pregnant or more like being hungry?

What I mean is that pregnancy is an all or nothing affair.

It's like being alive or being located above the equ by contrast, admits of degrees,

taking in everything from Winnie the Poos hankering for a little something

to the ravenous and permanently unquenched appetite of the cookie monster.

If knowing is like this, then you could have more or less certain knowledge of things.

You would presumably be prepared to say, for instance, that you know how old you are, but if pushed, you might admit that, though you do know this, you aren't as absolutely certain about it as you are about say the fact that 2 plus 2

equals 4. After all one could devise remotely possible scenarios according to

which your actual age is different. Perhaps in your first year of life, you were mixed up with another baby who had a different birthday.

Or perhaps your parents are spies who falsified your birth certificate.

If you start taking such scenarios really... who falsified your birth certificate.

If you start taking such scenarios really seriously,

you might conclude that you don't really know how old you are after all.

Then you would be starting to think that knowing is like being pregnant.

Real knowledge would have to have the highest degree of certainty,

and if this sort of certainty is absent, then knowledge too would be lacking.

Often it is the skeptic who insists that knowledge is like this.

The philosopher who leaps to mind immediately is Descartes.

In his meditations, he famously subjects all his beliefs to rigorous doubt,

inspecting them to see whether any of them rise to the level of absolute certainty.

...