Response to Siearra/Is Priori Knowledge Important

The post by Siearra titled "Is Priori Knowledge Important" posed a few topics for me to discuss.  She brought up the issue of right and wrong of good knowledge and not good.  She asks, "How, as human beings, are we supposed to know what knowledge we come across is good or not?" It is interesting to consider the subjective input each individual has, and how will that impact the classifications of good/evil.  Plato had an objective view that all humans posses one inherent opinion of good knowledge and would therefor recognize it immediately.  
Siearra's grand question of what is the difference between right and wrong can be answered simply according to Plato; with an objective base each person will do what society deems acceptable and "right" taking into account the ways their actions contribute to society and the attainment of reason. There is no room of subjective classifications or moral confusion.