In novels, stream of consciousness goes inside the hero’s head and you can read what he’s thinking. You don’t have that in television, and so I thought that if I took a perfect person and divided him into three parts, I could have the administrative, courageous part that would be the Captain; the logical part who is the Science Officer and the humanistic part with the Doctor. Then when something comes up, the Captain could say, ‘I don’t know, fellas. We must do it,’ and Spock would say ‘However, the logical thing is…’ and the doctor would say, ‘Yes, but the humanity of it,’ and I could have them talking about it without having stream of consciousness, and it worked.

Gene Roddenberry (via leighway)