'Two principles'
Note from The Achievement of France in
Part 1 of Reflections On The Revolution

It did not suit Burke here to add to the spirit of gentleman (i. e. honour) and religion, a third great impulse that has guided human affairs, viz. Liberty.

NB. Grieve misses Burke's point that the two principles (honour and morality) are restraints upon behaviour; the spirit of liberty is merely a resentment of restraint. — Philip Atkinson