For consideration this afternoon.

Locke writes

If the signification of the names of mixed modes are uncertain because there be no real standards existing in nature to which those ideas are referred and by which they may be adjusted, the names of substances are of a doubtful signification for a contrary reason, viz., because the ideas they stand for are supposed conformable to the reality of things, and are referred to standards made by nature. In our ideas of substances we have not the liberty... to frame what combinations we think fit to be the characteristical notes to rank and denominate things by. In these we must follow nature, suit our complex ideas to real existences, and regulate the signification of their names by the things themselves, if we will have our names to be the signs of them, and stand for them. [ECHU Bk. III.VIII.11]

Conglomerate that in your thinking, if you will, with Grice remarking on his own work, giving this account of an argument in "The Causal Theory of Perception":

statements to the effect that somebody was having a sense-datum, or had a sense datum or was having a sense-datum of a particular sort, are to be understood as alternative ways of making statements about him which are also expressible in terms of what I might call phenomenal verbs like "seem" or, more specifically, like "looks," "sounds," and "feels."

[The view just given]may run into trouble. It seems to me to be a plausible view that the applicability of phenomenal verbs is itself to be understood as asserting the presence or occurrence of a certain sort of experience, one which would explain and in certain circumstances license the separate employment of a verb phrase embedded in the phenomenal verb-phrase; for it to look or seem to me as if there is something red before me is for me to have an experience which would explain and in certain unproblematic circumstances license the assertion that there is something red before me. It will be logically incoherent at one and the same time to represent the use of phenomenal verbs as indicating the existence of a basis, of some sort or other, for a certain kind of assertion about perceptible objects and as telling us what that basis is. ["Retrospective Epilogue" in Studies in the Way of Words, sec. Strand One.]

Compare now with Locke, again, ibid sec. 17, about "gold":

I think all agree to make it stand for a body of a certain yellow shining colour; which being the idea to which children have annexed that name, the shining yellow part of a peacock's tail is properly to them gold. Others finding fusibility joined with that yellow colour in certain parcels of matter, make of that combination a complex idea to which they give the name "gold" to denote a sort of substances; and so exclude from being fold all such yellow shining bodies as by fire will be reduced to ashes... Another by the same reason adds the weight... [N]o one can show a reason why some of the inseparable qualities, that are always united in nature, should be put into the nominal essence, and others left out: or why the word "gold," signifying that sort of body the ring on his finger is made of, would determine that sort rather by its colour, weight, and fusibility, than by its colour, weight, and solubility in aqua regia... For by what right is it that fusibility comes to be a part of the essence signified by the word "gold," and solubility but a property of it? ...[N]o one has authority to determine the signification of the word "gold"... more to one collection of ideas to be found in that body than to another.