Frege On sense and Reference - question about something Frege says about Sense vs Ideas

Question

Frege says in On Sense and Reference that "The same sense is not always connected, even in the same man, with the same idea." (pg 26). What does he mean by this? I do not see how this can be possible.

(note that my understanding of an idea (as used by Frege) is similar to a memory, since both are mental pictures, so to speak.)

If I am considering the horse Bucephalus, if I saw the horse and thus acquired some sense of Bucephalus, and also then an idea of the word Bucephalus, how would those ever come apart? If they can in some significant way, surely I can think about, consider, play around with (etc) the sense without any idea. But how could I ever assert anything about Bucephalus without any idea of Bucephalus? I could say it was a strong horse, but I could only know that myself if I looked and got an idea of the horse. Otherwise, if someone asked "how do you know that" I would have to say "because I saw it" if I want to be fairly certain about my assertion. But then I am just deferring to an idea after all. Why? Because in saying something about what you see, you say something about what you can immediately see in your perception or an idea, but what you immediately see in your perception just is an idea once you consider it. What else would an idea or mental picture be? If you say sense has nothing to do with seeing and thinking, then what is "sense"? I thought it was a mode of presentation, which has to do with seeing and thinking, which seems to require ideas? Or, if sense is the thought expressed by a sentence, what does this thought amount to if it is not, in any way, an idea?

In short, how does idea and sense come apart? Frege says "Such an idea is often saturated with feeling; the clarity of its separate parts varies and oscillates" but the extent to which an idea itself is impacted by emotion and a loss of clarity is very much exaggerated it seems. That is, if the thought expressed by some sentence s was "that Aristotle was hairy" then it seems such an expressed thought means nothing without the existence of an idea, since if you had a different idea you would have a different sense (maybe that "that Aristotle was slightly hairy"). At least there seems to be a strong correlation.

I do not even see how to understand his claim here, that sense is different from idea, and more importantly for this post, how the same person can have the sense of something and an idea of it and those two be separate. An example of such being possible would be appreciated!

Answer 1

I think the easiest way to grasp this is by using Frege's 'morning star' paradox. The paradox involves a simple naïve observation of two objects:

• The morning star (a), brightly visible in the early morning sky
• The evening star (b), brightly visible in the late evening sky

Now, we know from scientific investigation that the morning star and evening star are both the planet Venus (c). We also know that propositions a=a, b=b, and c=c are true, from simple identity. But the proposition a=b (or a=c) is clearly not a simple identity. One can know about a without knowing about b and vice versa; one can know about them both without knowing they are the same thing. Proposing a=b implies something more than simple identity, and thus something more than simple denotation.

The way Frege addressed this is to separate sense, idea, and denotation, to wit:

• The sense is the simple observation (in this case, the simple observation of two separate 'stars')
• The idea is the mental representations that attach to these two simple observations. The names 'morning star' and 'evening star' are part of the idea of each of these things, along with any factual, mythological, sociological, metaphorical, etc content that pertains separately to each 'sense'
• The denotation is the underlying real object that each of these ideas points to, in this case the planet Venus.

Frege is trying to clear up a logical problem in which two apparently different denotations are factually (if unknowingly) the same denotation. Analytic philosophy of that period was working on the presumption that denotation was one-to-one connection between a mental object and a physical object — a presumption that really helped in the construction of logical propositions — and Frege was trying to preserve that by incorporating senses as a kind of indirect denotation or denotation by proxy. Russell didn't much like the approach, but his argument against it was fairly weak, so…

Answer 2

See Gottlob Frege, The Thought. A Logical Inquiry (1919):

I call a thought something for which the question of truth arises. So I ascribe what is false to a thought just as much as what is true.

Therefore two things must be distinguished in an indicative sentence: the content, which it has in common with the corresponding sentence-question, and the assertion. The former is the thought, or at least contains the thought.

[it is] ecessary to recognize an inner world distinct from the outer world, a world of sense-impressions, of creations of his imagination, of sensations, of feelings and moods, a world of inclinations, wishes and decisions. For brevity I want to collect all these, with the exception of decisions, under the word " idea ".

No other person has my idea but many people can see the same thing. No other person has my pain. [...] every idea has only one bearer; no two men have the same idea.

I now return to the question: is a thought an idea? If the thought I express in the Pythagorean theorem can be recognized by others just as much as by me then it does not belong to the content of my consciousness, I am not its bearer; yet I can, nevertheless, recognize it to be true. However, if it is not the same thought at all which is taken to be the content of the Pythagorean theorem by me and by another person, one should not really say "the Pythagorean theorem" but " my Pythagorean theorem ", " his Pythagorean theorem " and these would be different; for the sense belongs necessarily to the sentence. Then my thought can be the content of my consciousness and his thought the content of his. Could the sense of my Pythagorean theorem be true while that of his was false?

Thought (like sense, the ‘thought’ (Gedanke) is a special Sinn: the Sinn of a sentence) is the "conceptual content" of a linguistic expression: something that is communicable, i.e. intersubjective. Frege says: "the apprehension of a thought - thinking." And: "In thinking we do not produce thoughts but we apprehend them. [...] The apprehension of a thought presupposes someone who apprehends it, who thinks. He is the bearer of the thinking but not of the thought

See Sense and Reference (1892): "The referent and sense of a sign are to be distinguished from the associated conception [Vorstellung]. If the referent of a sign is an object perceivable by the senses, my conception of it is an internal image, arising from memories of sense impressions which I have had and activities, both internal and external, which I have performed. Such a conception is often saturated with feeling; the clarity of its separate parts varies and oscillates. The same sense is not always connected, even in the same man, with the same conception. The conception is subjective: One man's conception is not that of another."

In conclusion, thoughts [senses], like numbers, are abstract objects that live in the outer world, while ideas [conceptions] live in the mental world and are subjective. We have our own ideas but we think thoughts that are not our own.

See also Gregory Currie, Frege on Thoughts (Mind, 1980).

---

Added Dec,12

Maybe we can try to disentangle the issue about the mental vs the objective with a reference to later Wittgenstein and the so-called Provate language issue. See PI:

§253. "Another person can't have my pains." —Which are my pains? What counts as a criterion of identity here? [...] §256. Now, what about the language which describes my inner experiences and which only I myself can understand? How do I use words to stand for my sensations? —As we ordinarily do? Then are my words for sensations tied up with my natural expressions of sensation? In that case my language is not a 'private' one.

Thus, in a nutshell, we can communicate each others because we have shared meanings and not because we transfer "inner" ideas.

From Frege's point of view: we communicate because there are shareable contents that are different from unshareable mental acts and ideas.