Originally Posted by Captain Tom Coughlin
I think that they are intelligent, and make up a significant portion of a joined Trill's personality. They hint at that often, and I think it goes deeper than mere memory. That would suggest that the symbionts are sentient beings, which is how I've always viewed them.
That makes obviously more sense but DS9 also suggested that the personality of Dax changes quite a bit between hosts so the Dax symbiont could be more of a link between the different Daxes than an actual part of the Dax personality.
Just a crazy image I have somehow of the Trill, as I said your post makes far more sense.