A horse walks into a bar. The bartender asks the horse if it’s an alcoholic considering all the bars it frequents, to which the horse replies “I don’t think I am”. POOF! The horse disappears.
This is the point in time when the philosophy students in the classroom begin to giggle as they are familiar with the philosophical proposition of cogito ergo sum “I think therefore I am”.
But to explain that concept beforehand would be putting the Descartes before the horse.