Full Idea
Every man is led by nature to attribute to himself the free determination of his own will, and to believe those events to be in his power which depend upon his will.
Gist of Idea
Our own nature attributes free determinations to our own will
Source
Thomas Reid (Essays on Active Powers 1: Active power [1788], 5)
Book Reference
Reid,Thomas: 'Inquiry and Essays', ed/tr. Beanblossom /K.Lehrer [Hackett 1983], p.306
A Reaction
I'm happy to say we are all responsible for those actions which are caused by the conscious decisions of our own will (our mental decision mechanisms), but personally I would drop the word 'free', which adds nothing. We are not 'ultimately' responsible.