I was thinking about something similar recently. Thought is a manipulation of something, yes, but not only of symbols. Thought is basically a manipulation of qualia (basic sensations, such as red, the sound of a french horn playing a specific note, anger, or pain). Words are sets of qualia. For me, at least, they are linear strings of various sounds. When I think, I hear the words in my mind. It is possible that others may think differently- perhaps they see the words instead. The point is, that language, sounds standing for meanings, is not the basic mode of thought. The most basic way of looking at thought is that it is the manipulation of sets of qualia which can possibly represent other sets of qualia. This is crucial: there is no such thing as abstract meaning. The only things a person can experience are qualia. A mind cannot perceive meaning as anything other than a set of interrelated experiences. As it relates to the topic of this node, first, mental symbols are sets of qualia, and second, if these symbols are dereferenced, they lead, not to some intangible meaning, but to more sets of qualia.