As 'jedoch' arises as the combination of 'je' and 'doch', I am wondering how to deduce the fundamental meaning of 'jedoch' from those of 'je' and 'doch'?
It's literally "all though"
"Je" means as much as "every", often in relation to time but not only. It is a short particle, that has a lot of meanings depending on the speaker, context and perspective.
"immer doch!" as a colloquial interjection is used differently, in an affirmative tone, "of course any time", but it shows how doch is understood. It opposes any possible doubt.
Regarding the comments to the question:
Aufhören: whence Aufhorchen, means to listen up, quite literally, which often requires to stop doing anything else.
Cargo: carrus + -icō (lt. carrico, to load) ... from Gaulish karros, from Proto-Celtic *karros (“wagon”). -ico is "From -ō suffixed to words with stems ending in -ic (including -icus), which was reinterpreted as part of the suffix.", where -ō is "suffixed to the roots of verbs, forms masculine agent nouns". So, yeah, it's got some bastardization going in.
I guess the question stems from the Wiktionary entry for jedoch.
My etymogological dictionary states that je meant always, forever (Old High German io, eo). In compounds such as jedoch, jeder, jeglich, immer, the original meaning has been lost and is not recognizable any more.
I'm just guessing. If je means always, forever, as stated in the answer above, it reinforces the concession and means something like "but despite of everything" or "but always taking into consideration".
Note that several synonyms of jedoch (see http://www.dwds.de/?qu=jedoch) have a similar component:
- trotz allem
The English however works in the same way.
Note that jedoch and doch are also similar in meaning, namely introducing a concession. So while Robert and the others aren't wrong (you can't always guess the meaning of a German word by dissecting it into its components), there still is a logic link.
The word "jedoch" is not deciphered by the parts "je" and "doch". In my opinion is also not originating or tied with from "jeglich", "immer" or so on. "Jedoch" means the contradiction/negation of a earlier sentence/part/intention or statement in a conversation/discussion:
"Ich würde gerne etwas essen, jedoch habe ich keinen Hunger" "Ich würde gerne mit zum Schwimmen kommen, ich habe jedoch keine Zeit".
Jedoch is something like the rejection of an earlier intention, perhaps better translated with the english "but" like in the sentence: "I would like to go to the cinema, but i have no spare time".