I'm in the middle of Philebus right now, in which Plato claims that pleasures and pains can be true or false to the extent that they are "based upon realities" (40D). Socrates manages to convince his debate opponents, who by this time in Plato's works are becoming less and less of real people and more of cardboard stand-ins to tell Socrates "yassuh"--or maybe all of Athens was tired of Socrates by this time and agreed merely to shut him up. I, at any rate, am unconvinced.
Plato talks quite a bit about hope and dread as pleasure and pain, so let's use these as examples. I can look forward to winning the lottery, say, and I can plan what I will do with my millions. (Since it's me in this example, I will probably fill a notebook with lists, perhaps color-coded.) But I'm not going to win the lottery, not even if I enter it--that hope, that pleasure is not at all based upon reality. But it's still pleasure. I will still gain satisfaction, however temporary, from my detailed million-dollar budget. When they announce the winning numbers Saturday night, it will become immediately apparent to me that my pleasure was based on a false reality. That doesn't mean it wasn't pleasure.
Likewise, if I panic--as I often do--and fear that I'm going to exhaust my meager resources and overdraw my checking account, the pain and the terror this causes me is no less painful and terrifying for being built on a (usually) false assumption. No, the pain is real, and the reality of the pain (to reiterate, as opposed to the reality of the basis of the pain) only adds to the reality of my pleasure when I check my account balance and find an acceptable number of electronic dollars. Pain and pleasure, emotionally speaking, exist whether or not they are attached to legitimate, that is to say, real, objects. Plato's suggestion to the contrary is an attempt to bend emotion to the intellect--an admirable attempt, but one that's not actually going to lessen emotional pain.
The argument gets stickier when we're talking about physical pain, so let me talk briefly about the physiological and psychological bases for physical pain. (I am no neuroscientist, so bear with me.) The June 30 issue of the New Yorker features a piece called "The Itch," which deals with a young woman who has an itch with no physiological basis. That her pain is not based on a physical reality does not stop her from seeking real comfort and pleasure--she scratches her head so much and so deeply that
One morning, after she was awakened by her bedside alarm, she sat up and, she recalled, "this fluid came down my face, this greenish liquid" . . . Only in the Emergency Department at Massachusetts General Hospital, after the doctors started swarming, and one told her she needed surgery now, did M. learn what had happened. She had scratched through her skull during the night--and into her brain.M.'s itch, it turns out, is caused by nothing in particular, a variation on "phantom limb pain," in which a person whose arm or leg has been amputated nevertheless feels pressure and, oftentimes, pain on the affected area. I can't think of any better example of real pain caused by nothing in the realm of reality.
Unless it's this: When I read "The Itch," I began itching wildly all over my body. The power of suggestion caused a real pain in me based on nothing in reality. One could, I suppose, respond that I was responding to something unreal. But then there's Samuel Hafenreffer's 1660 definition of "itch," which has apparently not been improved upon in the intervening years: "An unpleasant sensation that provokes the desire to scratch." Unreality begets reality.