Upon reflection, I plead guilty to Michael Brady's charge that I chose badly, too rhetorically, when I said our first thought when we encounter a new and complicated subject can be "weightless". For examples I conveyed that in Philosophy 101 at Brown when the problems of "cause", "belief", and "meaning" were introduced, my first thoughts were light-weight, trifling, thin, meager. Michael opined that I should have said 'light-weight' to begin with. I accept his correction.
My basic point was that our alleged particular "thoughts", our "idea-notions", are, among other things, transitory. They evolve as we think about them more, they pick up more, call it, substance. In the last few days, we've seen this on the forum as the subject of "essence" was introduced and then elaborated on. Mando has said he wants his sculptures to "express the essences" of their subjects' William wrote: "Define essences". Saul, who is good at projecting a tone of finality, replied with one line: "the minimum it takes for a thing to be differentiated from another thing" When it was pointed out that this is ambiguous. "E.g. do you mean differentiate a tiger from a lion, or one tiger from another tiger?" Saul's first notion proved not to be final; he "evolved" his definition a bit: "the essence of something [is] the minimal conditions that allow us to distinguish it from another thing (of a different kind or order)." In response to this, it was pointed out to Saul: "My name and address differentiate me from anyone else in the world. Would you call them my "essence"?" To which Saul advanced his definition by adding the (undescribed) notion of "significant": "If that combination is the most significant difference we might identify then I would say yes" Saul then elaborated: "I do not think there is any essential difference between one human and another." Saul, at this point in his developing idea, feels the "essential" thing is a matter of what he calls "kind" (roughly what Kripke et al term "natural kinds".) And it went on like that, with Saul refining his original notion. Saul is not alone in this. Any pertinacious thinker will find his new ideas evolving if he thinks on them long enough. My point: We have a tendency to talk of "THE concept of XXX" as though everyone who thinks of XXX conjures the same notion in the mind, or "my idea of" as though it is something fixed in our consciousness. In fact all notion is transitory - morphing like a writing cloud.
