Since the beginning of the study of psychology, scientists have been arguing about the topic of whether therapy should be considered an art or a science. There is very strong evidence to support both theories, and that is why no real decision has been made. This topic is very individual to each person studying counseling and therapy and for the most part, just "swept under the rug". However I feel that when teaching the skill of counseling and therapy to others therapy should be considered an art rather than a science.
In my personal opinion, therapy is an art because therapy is personal and individual. Something that cannot be studied perfectly should not be considered a science. Even though therapeutic interventions cannot be offered [ethically] without having been supported by research, the studies that have been conducted cannot tell us how individuals have personally benefited from that therapy. Also, the average/mean benefits from group therapy are different than the score of each individual person in that group. .
If therapy is a science, we should be able to come up with specific interventions and theories that will help people. However the fact of the matter is, is that what works for one person may not work for all people, or even two people with the same disorder. Can two people even have the exact same disorder or problem? I believe that the answer is, no. For this reason therapists must take on an eclectic point of view. They need to establish what is most effective for that individual client, use therapeutic factors, and select aspects from different theories to be able to help.
There are also therapeutic skills that cannot be taught easily. Things like warmth, empathy and the therapeutic relationship/alliance can be taught, but only when the therapist truly feels that empathy and warmth does it start to have an effect on the client. Chemistry needs to be present between the therapist and client for there to be change and improvement.