The idea is cute. If my instinct is right, most of the cards are broken in their current version, but it might be possible to work things out.
The first thing I'd do first is to think about how much a knowledge token is worth. Based on what they do, I'd say they're worth between 1 and 1,5 coin tokens (this is an uninformed guess, based solely on intuition). So, that's how I'll look at the cards.
so, I'll quickly go through all the cards and explain what problems I'm seeing.
Philosopher
$5 - Action
+3 Cards
Take 2 Knowledge tokens.
pretty sure this is too strong. with two of them, you can topdeck one each turn and still have enough left to topdeck gold etc.
Foundry$3 - Action
+1 Action
Choose one: Take 2 Knowledge tokens; or return any number of Knowledge tokens, and gain a card whose cost in Coins exactly equals the number returned.
here, the first part might be okay, but the workshop is pretty useless. since you don't get the first option, you have to pay 2 + price to gain a cord, so to get a card costing 5$, you have to pay 7 tokens, which is obviously more than it's worth.
Experiment
$4 - Treasure
$2
When you gain this, take 3 Knowledge tokens.
this looks broken too, as 3$ and 4$ are very close, and a card costing 4$ should not be strictly better than silver. I think it could easily cost 5$ and still be superior to royal seal or stash.
Surgeon
$4 - Action
Trash a card. Take a Knowledge token per Coin it costs.
The closest match here is salvager, and I'll say that this one is much better, as a knowledge token is worth more than 1$. They get better later though, and you want salvager early, so it might be more complicated.
Archive
$6 - Victory
Worth 1 VP for each Knowledge token you have at the end of the game.
When you gain this, take 2 Knowledge tokens.
Well, this one is a clear case, and unfortunately, I doubt that it can be fixed. A victory card that counts itself has already been made and turned into duke; this one does the same with the added bonuses of a) being twice as good, b) giving you a way to spend some of your future VP's in game and c) a way to boost VP when other cards that provide knowledge tokens are present. as is, you would but it over province in every game, but even if the powerlevel is right, all it can ever be is a swingier version of duke.
Surveyor
$2 - Action
+1 Action
Reveal the top card of your deck. If it is a Victory or Curse card, take a Knowledge token. Otherwise, put it in your hand.
and this one is too weak. compare it to vagrant, and you have
-> reveals victory card or curse: lab vs gain one knowledge token
-> reveals shelter or ruins: lab vs cantrip
-> reveals anything else: cantrip vs cantrip
so, case #1 and #2 vagrant is clearly better, and case #3 they're identical.
