I put one point into Linguistics but I cannot seem to use any curses yet.
I don't know if you can curse with one point, but I could use Vrosk Omn Charname and see their stats (similar to the awareness perk in fallout, though less specific) and Maen Lumen for torch light. I have 3 points in it and I'm using all the words of power in Erlein's handbook (davi, shoar and grafitus), some stealing with vrosk rife. I haven't tried using curses yet, I imagine some will work with 3 pts, but a lot wont.
So I found a riddle imp in the cave in Lumen Targ, but even with a point in philosophy, I have no choice except to fight it? I think it should ask some sort of riddle?
I could only fight him with 1 point in philosophy, not sure about
Ninjerk's experience. The entire reason it asks you who steps forward is so that you can choose the character who you think has the best aptitude(s) for the dialogue.
Philosophy also lets you steal stats from your companions via one time use Imps in a Jar. You can get one in Lumen Forten if you have 1 point in philosophy, but you can only steal Perception I believe. It takes more points in philosophy to steal other attributes.
On another note, I'm a keyboard-heavy player and this new patch is making combat a lot of fun. Not having ranged guys occasionally go ape-shit and charge into combat reduces the tedium. I still wish the Stop All button only worked for the character selected (FYI it affects the entire party regardless of selection) and was hotkeyed, but it's fun. The power curve at low levels seems very 1-2nd ed. AD&D-ish, where one level makes a huge difference. I just cleared out the encampment of 4 named bandits outside Lumen Targ at level 3, where it was impossible at level 2. It was a good low level encounter, had a nice positioning element and the enemies used spells as well as melee and ranged.