Before Epicurus. Plato had popularized the idea that humanity lives jn the equivalent of a cave, wirh our senses deceiving us and incapable of allowing us to discover truth. Likewise the Skeptics taught that knowledge is impossible, and the various religions taught that reality is created snd controlled by god, and only through faith and prayer is any knowledge of truth possible.
Epicurus stands firmly against these opposing views, holding that Nature does equip us with faculties of knowledge sufficient for our needs. These faculties, taught Epicurus, are our bodily senses , our feelings of pain and pleasure, and a faculty of appreciating or noticing patterns known as “anticipations.”
Illusions do not show that eyesight is fallible; it is the task of reason to process the information they provide.
There are many examples of visual illusions, but we fool ourselves; misjudgments are not the fault of the senses but of our processing the information the senses provide
The man who argues that nothing can be known confesses that he himself is ignorant.
The ultimate validity of the senses cannot be refuted, because any attempted refutation depends for its proof on the senses.
If you cannot explain a seeming contradiction, it is better to accept an incorrect theory than to give up those conclusions that you have already had sufficient facts to verify to be true.
Some events in life - like Romantic Love - are intoxicating, and in order to avoid undue pain you must avoid - not the event itself - but the intoxication.
What do these faculties allow us to conclude? That is a question for Day Four