This shows me that teachers are professionals under the Service characteristic. The second of the six characteristics Shulman mentioned was Theory. Theory is the assumption that the teacher possesses the knowledge and the skills to teach others. For example I am an ELED major, a school that might higher me an myself would both have the theory that I posses the knowledge and skill to teach grade school. The third reason teaching is a profession is Practice.
Teachers are professionals because they practice in schools.
There are different types of places teachers practice. Teachers work in public and private schools, and also in state and private colleges. Judgment is the fourth characteristic Shulman presents to us. Teachers need to have very good judgment, because of the many decisions they face. The fifth characteristic is Learning from Experience.