zompist bboard

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A grammar needs examples that use part of the lexicon.

An entry in the lexicon is often not complete without information about grammar.

Why not both at the same time?

I don't think it's possible to make a "good" conlang without iterating between the two.

Without a lexicon, you can't really make sentences or check how various affixes react to their respective roots. Without grammar, you have no working derivational morphology and your lexicon can only be very rudimentary.

I can only agree with the posts above and would like to add that, given that you derive your conlang from a protolang, also sound changes go hand in hand with grammar and lexicon.

However, it's still possible to toy around with first random words, ideas, prototypes in the form of word roots without paying too much attention to grammar. Sooner or later you will have to deal with mentioned elements though, it's inevidable. If you plan to design your very first conlang I recommend reading various tutorials/howtos first, like the language construction kit, it may be very helpful to get a grip of it.

Good luck.

In a priori languages (sometimes called philosophical languages) the system is prior, no need lexicon...
In fact no need to lexicon at all...

That's a posteriori "from the later", which means it is based off of a natural language. a priori means "from the former", but it refers to languages which are not based off of currently existing ones (song pre-existing lexicon). Many conlangs are in between the two extremes, but they tend to be labeled by the extreme their closer to. If the phonology or orthography is based on a real language it usually is considered to not count as a posteriori - the influence has to be in syntax, morphology and/or lexicon. When I use the terms, I usually refer specifically to the basis of the lexicon, but I've found that other people have broader definitions.

In those a priori (philosophical) languages, 1sense=1sign=1sound...
The system is the triple equality, you can work about it using meaning or writing or phonology...
The lexicon is the product...

Nobody uses "a priori" to mean a philosophical language, but rather as a conlang that isn't derived from a natlang (though the precise details do vary)

All the pre-internet books did...
But the acceleration of the sliding of meaning is not the subject of the post ...
Let's talk, if you want, about philosophical language (even if scientifical would be more appropriate)...
Those are centered on the production of lexicon, but no lexicon is really required to make the job...

I have no idea how you got the impression that Wikipedia claims what you say it does, all it says is that philosophical languages are a subset of a priori languages.

We'll have to open a new thread for that...