I went to hear Matthew Wood, one of my favourite herbalists speak yesterday, it was just lovely to be in his company, and he is just as you would imagine him. Absent minded, rambling, and VERY knowledgeable. He spoke about the energetics of herbs, and for me personally, he gave me another perspective which I am going to integrate into my practice, though it will take me a while, and I my practice has been going that way anyway.
He uses small doses, almost homeopathic, of herbs, whereas I was taught material doses, but to do this, you have to understand the energetics of herbs and people, and be a matchmaker, to put the two together. He went through in great detail 6 tissue states - irritation, relaxation, contraction, depression, atrophy, toxicity and matched their treatment to herbal energetics and their actions such as hot, cold, dry, damp.
I had been aware of this, and read his book on herbal energetics, but hearing him made it come alive. In particular, what made sense, was his view of different depths of herbal actions - for example, cold herbs are cold in 1st degree, where they will cool you on a hot summers day eg vinegar, whey, salads. Cold in the second degree, where they will reduce fevers (febrifuges), cold in the 3rd degree where they have a sedative influence on the nervous system eg callendula or cold in the 4th degree where they act as anasthetics, put you to sleep and reduce nerve sensitivity and excitment eg wild lettuce, californian poppy. These can then given to people depending on the depth of 'hotness' they present with.