In Inception, in the beginning dream scene, Mal remarks that a painting looks like Arthur's taste. Cobb replies that, "Actually, the subject is partial to post-war British painters."
What subject is that?
Any other insight into the significance of that turn of dialogue? The subject being partial to post-war British painters doesn't seem to exclude Arthur's hypothetical taste for it.
The Subject is the person whose subconscious is of an interest to the group. From Wikia:
The subject's role is to populate the dream space created by the dreamer with projections of his or her own subconscious.
In this particular case, the subject is Saito. The group inflitrates his mind to extract information from it, which they believe is in his safe. Cobb is saying that the pictures are there because Saito likes them, not because of Arthur.
In the original screenplay it's made explicitly clear that Saito is the 'subject'.
Mal sips champagne as she studies a painting by Francis Bacon.
MAL: Looks like Arthur's taste.
Cobb is looking down through the window at the GUARDS patrolling the castle at ground level.
COBB: Actually, Mr. Saito is partial to postwar British painters.
Cobb explains a little later how the dreamer/subject work together in tandem (willingly or unwillingly) to create a dream-share.
COBB: Sure-you are the dreamer, I am the subject. My subconscious populates your world. That's one way we get at a subject's thoughts-his mind creates the people, so we can literally talk to his subconscious.
