Plato thought writing was a lie:

> If men learn this, it will implant forgetfulness in their souls; they will cease to exercise memory because they rely on that which is written...And it is no true wisdom that you offer your disciples, but only its semblance, for by telling them of many things without teaching them you will make them seem to know much, while for the most part they know nothing, and as men filled, not with wisdom, but with the conceit of wisdom, they will be a burden to their fellows.

Basically, reading writing (without instruction) will only make people seem like they know stuff, by parroting others, when in fact, they know not much of anything.