Is teaching an art or a science? I think this centers around the idea - are there natural teachers? Can you learn to teach? How does one become an effective teacher?
I think of teaching as more of an art. It's a form of individual expression that can be approached and executed in so many different ways. At the same time, I feel there are some scientific elements as well - rubrics, formulas, grading systems, and the like. Also, I think teaching can be "gotten down to a science" in some instances such as when a teacher teaches the same class for many years and really has found a method that works for that particular class in terms of execution and student success.
I do think some people have more of a knack for teaching than others and seem more natural at it. I think people who are considered "natural teachers" are those who have strong interpersonal, empathetic, and listening skills. Having these skills allows them to communicate effectively and to also see students' perspectives about the subject matter at hand. I do think people can learn to teach, but I think it comes more easily to those that have these skills.
Like most professions, becoming an effective teacher takes practice. I also think the willingness to try new ideas and approaches to teaching helps, along with being flexible. Effective teachers seem to be those that can strike the balance between the needs of the class and individuals in the class. There should be individual attention when needed, but not at the expense of the entire class.