When you cast a spell, Inexorable Tide’s triggered ability is put on the stack on top of that spell and will resolve before the spell resolves (Ruling [2011-01-01]). Inexorable Tide’s trigger will proliferate when it resolves, which can add a +1/+1 counter to Evolution Witness only if the Witness already has at least one +1/+1 counter at that moment because proliferate chooses permanents that already have counters . If Evolution Witness has no counters, you can activate its Adapt ability in response to the Inexorable Tide trigger to put two +1/+1 counters on it; that will cause the Witness’s “Whenever one or more +1/+1 counters are put on this creature…” triggered ability to trigger. After that trigger(s) resolves, Inexorable Tide can resolve and proliferate again, adding another +1/+1 counter and causing another Witness trigger (if the Witness now has counters) (Ruling [2011-01-01]).
Step 1
You cast a spell. Inexorable Tide’s triggered ability is created and put on the stack on top of the spell (Ruling [2011-01-01]).
Step 2
Priority is given after the spell is cast and the Inexorable Tide trigger is on the stack. You may activate Evolution Witness’s Adapt ability in response to the Inexorable Tide trigger if you have the mana and priority; the Adapt activation is an activated ability and goes on the stack above the Tide trigger.
Step 3
If you activate Adapt in response and it resolves, it will put two +1/+1 counters on Evolution Witness (its Adapt text). Because one or more +1/+1 counters were put on the creature as that effect resolved, Evolution Witness’s triggered ability (“Whenever one or more +1/+1 counters are put on this creature…”) is created and put on the stack; that triggered ability will target a permanent card in your graveyard when it’s put on the stack.
Step 4
Those Witness triggers (from the Adapt resolution) will resolve in last-in-first-out stack order, and when each resolves it will return the targeted permanent card from your graveyard to your hand (assuming the target is still legal).
Step 5
After any responses are finished and the Adapt-triggered Witness ability is on the stack, eventually Inexorable Tide’s trigger will resolve (Ruling [2011-01-01]). When it resolves, you proliferate . Proliferate can add a +1/+1 counter to Evolution Witness only if Evolution Witness already has at least one +1/+1 counter at that moment, because proliferate chooses permanents that already have counters .
Step 6
If proliferate adds a +1/+1 counter to Evolution Witness, that is another event of one or more +1/+1 counters being put on the creature, so Evolution Witness’s “Whenever one or more +1/+1 counters are put on this creature…” triggered ability will trigger again and go on the stack (targeting a permanent card in your graveyard when the trigger is created).
Resolution
If you cast a spell, Inexorable Tide’s trigger is put on the stack and will resolve before the spell resolves (Ruling [2011-01-01]). Proliferate only affects permanents that already have counters, so if Evolution Witness has no +1/+1 counters when Inexorable Tide resolves, that proliferate won’t add counters to it; if you activate Adapt in response to the Inexorable Tide trigger and it resolves first, the two +1/+1 counters from Adapt will cause the Witness’s return-from-graveyard triggered ability to trigger once, and then when Inexorable Tide resolves it can proliferate and add another +1/+1 counter (causing another Witness trigger) if the Witness now has counters (Ruling [2011-01-01]).
