In the Summa Theologica, Prima Secundæ Partis, it is asked
"Whether man's happiness consists in pleasure?"
I think there are three objections, which I'm obviously paraphrasing here, so I don't want any philosophical nuts knocking down my door.
The first objection is that happiness DOES consist primarily in pleasure. The reason being that happiness is not desired for something else, but other things desire happiness. The second objection talks about the appetite. Something about how delight absorbs man's reason and causes him to hate other things (okay, I'm REALLY paraphrasing here!!). But still, man's happiness consists in pleasure. Objection 3 states that desire is meant for good. "Therefore happiness, which is the supreme good, consists in pleasure" (that is directly from the Summa).
To me, it looks like happiness, or a form thereof, is derived from pleasure.
St. Thomas answers that BODILY pleasure can't result from perfect good. Bodily pleasures result from good gotten from sense. Then he goes on to say something about man being a rational soul, and complete happiness can only be found if your soul's happy, and therefore, "bodily" pleasure does not equal happiness.
St. Thomas replies to the objections as such (again, from memory, so VERY paraphrased):
Reply to Objection 1. Delight is desired.
Reply to Objection 2. Everybody wants sensible pleasures, because the senses are perceptible.
Reply to Objection 3. Every delight results from some good, and some delight results from supreme good.
I had a discussion with my sister on Saturday, and it just got me thinking all about philosophy and what people believe. St. Thomas had a good point, but it seems to me that he goes back and forth a bit. He says that bodily pleasure doesn't equal happiness--he's right, but wrong at the same time. I think bodily pleasure brings a KIND of happiness. It's a euphoric happiness, a passionate happiness. A glow, if you will. It may not be lasting, but for that very moment, aren't you happy? Happiness doesn't have a timeline to it, last time I checked. Everybody needs some passion in their life.