Search function? ;)
http://www.pantheonmmo.com/content/forums/topic/1546/solo-play
http://www.pantheonmmo.com/content/forums/topic/1937/not-all-classes-should-be-able-to-solo
http://www.pantheonmmo.com/content/forums/topic/2967/solo-content
http://www.pantheonmmo.com/content/forums/topic/6052/solo-gameplay
http://www.pantheonmmo.com/content/forums/topic/7819/solo-ability
http://www.pantheonmmo.com/content/forums/topic/1566/should-you-be-able-to-solo-group-quests
From the FAQ:
1.4 Will you be able to solo in Pantheon?
Yes. While most content will be designed for groups, there will typically also be content that is soloable. Some classes may solo better than other classes.