Прилагательные обозначают постоянные признаки, а причастия — признаки, изменяющиеся во времени. Пример. "Плавучий маяк" — постоянный признак (расположенный на воде), это прилагательное. "Плавающий человек" — признак, изменяющийся во времени (тот, кто плавает сейчас), это причастие.
I guess this was an attempt to capture the difference between these two particular paradigms of verb forms ending in -чий and -щий, the former producing adjectives and the latter — present active participles.
Historically, both these paradigms were used to form participles — the former in Old Russian, the latter in Church Slavonic.
All participles (as a grammatical concept) had almost fallen out of use in speech by the beginning of the XVIII century, replaced by analytical constructs: крадущийся волк > волк, который крадётся etc. However, later on, in the XIX century, they experienced a revival of sorts, probably influenced by French.
Here's what happened up to that point:
Old Russian participles were repurposed as other parts of speech.
Here's their declension table for the short first person singular:
| Case |
M |
F |
| Nom |
несa, видя |
несучи, видячи |
| Acc |
несучь, видячь |
несучу, видячу |
| Gen |
несуча, видяча |
несучъ, видячъ |
| Dat |
несучу, видячу |
несучи, видячи |
| Inst |
несучемь, видячемь |
несучею, видячею |
| Loc |
несучи, видячи |
несучи, видячи |
(Gorhskova, Khaburgaev, Историческая грамматика русского языка)
The nominative forms have been repurposed as adverbial participles (деепричастия): я живу, неся свой крест (= я живу, несущий свой крест); я иду крадучись (= я иду, крадущаяся). As originally nominative forms, adverbial participles can only describe actions of subjects in the nominative (although in the modern language, they technically modify the verb of the predicate).
A relatively small number of oblique forms (around 30 or so) have been repurposed as adjectives expressing an intrinsic ability or inclination to do something:
- висячий "able to hang; designed to be hanging": висячий замок "padlock", literally "hanging lock"; висячие сады Семирамиды "Hanging Gardens of Semiramis"
- колючий "able to prick"
- гремучий "able to produce loud sounds": гремучий студень "blasting jelly", гремучая змея "rattlesnake"
All these adjectives started out as participles that would be висящий, колющий, гремящий in the modern language. Some of them have completely diverged in meaning from the original words: горячий, дремучий.
Church Slavonic participles, primarily only used to give otherwise Russian discourse the grand style, made a comeback and became Russian participles in their own right. They express the same thing as their analytical counterparts express: смеющийся человек / человек, который смеётся.
My question is: is it true that adjectives denote something constant, and participles, something temporary?
No, that's not universally true.
Participles are formed regularly from verbs and define the property of being an agent or a patient of the action expressed by this verb. Regularly is the crux here: participles are verb forms just like any other form, and all (or most) verbs are able to form them — even newly coined, borrowed or made up verbs. If we accept будлануть and курдячить as verbs, we must automatically accept будланувшая and курдячащая as their participles.
Adjectives are nominals (noun-like words) that define or modify nouns. Of course, all of them have their etymologies, and some of them are indeed derived from what used to be a participle in the past, but it's not a regular pattern anymore. You can try to form adjectives like **стрелючий ("able to shoot") or **программучий ("able to program") in modern-day Russian, but they would be taken to be clearly humorous novelty words, at most.
This distinction that you're mentioning is only relevant for parallel forms in -чий and -щий, of which there are perhaps only several dozen that have survived to this day.
