Quine:

Meaning, let us remember, is not to be identified with naming. Frege's example of 'Evening Star' and 'Morning Star' and Russell's of 'Scott' and 'the author of Waverly', illustrate that terms can name the same thing but differ in meaning. The distinction between meaning and naming is no less important at the level of abstract terms. The terms '9' and 'the number of the planets' name one and the same abstract entity but presumably must be regarded as unlike in meaning; for astronomical observation was needed, and not mere reflection on meanings, to determine the sameness of the entity in question.

...A felt need for meant entities may derive from an earlier failure to appreciate that meaning and reference are distinct. Once the theory of meaning is sharply separated from the theory of reference, it is a short step to recognizing as the business of the theory of meaning simply the synonymy of linguistic forms and the analyticity of statements; meanings themselves, as obscure intermediary entities, may well be abandoned.

I've quoted that enough but never used the most obvious example: 'Evening Star' and 'Morning Star',  'Palestine' and 'Israel'.

repeats: It makes no sense to refer to formal logic as philosophy. no fucking sense at all.