Does Wesley C. Salmon beg the question?

In Wesley C. Salmon's book 'Logic' (2. ed. 1973), he has a chapter entitled 'Logic and Language' in which he in paragraphs 'Definitions' describes language sprog as a conventional entity exemplified with the word cat. But is there a logical circle here? Salmon writes on p. 122:

"The meaning of a word is not a natural attribute which man discovers; meaning is given to a word by people who agree to let it have that meaning. For example, there is no intrinsic characteristic of the word 'cat' which makes it refer to feline animals; it does so because English-speaking people have adopted a convention to that effect. This is not intended to suggest that people once sat down at a conference table and formally decided the meanings of words. For the most part, these conventions, like many other conventions, have grown gradually and informally over a long period of time. As language continuous to grow and develop, these conventions are still subject to change. The important fact is that other conventions could have been adopted without being false or incorrect. […] A word has meaning if there is a convention establishing its meaning."

But if this is the case, the only evidence of anyone having 'adopted a convention' is that 'cat' now means what it does. The explanation seems to be circular: i.e. the concealed argument is: 'They must have adopted a convention because otherwise I cannot explain the regularity with which they agree about the meaning of 'cat'.

Kind regards,
Søren

I don't see a problem with this. I would paraphrase his argument as follows:

Words don't have intrinsic meaning, therefore, meaning is extrinsic, or established by convention.

At best, I would say one can argue that he can use more support for his premise, but perhaps he did elsewhere in the book.

I hope Salmon is not suggesting that word ‘conventions’ are singular, mutually exclusive and need be accepted by all. Multiple and unrelated definitions (meanings) of words have grown tremendously over the last fifty years. It has become ‘camp’* (my generation’s (Brit.) example; Millennials embrace a different usage) to co-opt the meaning of mundane words to elicit salacious meanings, perceptible only to certain sub-groups. Take a walk through The Urban Dictionary for beaucoup examples. Interesting question: how large does a sub-group need to be (i.e., accepting a selective word meaning) to allow for a Salmon ‘word convention’?

* “Something, esp. in art, decoration, theater, etc, so naively stylized, artificial, affected, old-fashioned, and inadequate to good modern taste as to be highly amusing and inviting to parody”