Examine expressions like: “having an idea in one's mind”, “analysing the idea before one's mind”. In order not to be misled by them see what really happens when, say, in writing a letter you are looking for the words which correctly express the idea which is “before your mind”. To say that we are trying to express the idea which is before our mind is to use a metaphor, one which very naturally suggests itself; and which is all right so long as it doesn't mislead us when we are philosophizing. For when we recall what really happens in such cases we find a great variety of processes more or less akin to each other. ‒ ‒ ‒ We might be inclined to say that in all such cases, at any rate, we are guided by something before our mind.
67.
But then the words “guided” and “thing before our mind” are used in as many senses as the words “idea” and “expression of an idea”.