It's important to understand that meditation is a constantly changing process, and as such, our brain is going to be in varying states throughout. At times, the act of meditation could lead us to being in a more receptive, less intellectually critical mindstate.
In fact, a lot of teachers will tell us that this is EXACTLY where meditation leads. They won't say that it's a less intellectually critical mindstate, they'll call it "being free of opinions" or "emptying your cup" or "thinking non-thinking."
Let's be clear. I'm not implying that being free of the continuous machinations of the intellect is a bad thing, because it's actually quite nice at times. But there are some dangers involved. The first is that people who are overly ambitious will strive to cultivate being in this "balanced state" at all times, and may actually create a scenario where they are less mentally aware and less in touch with reality as opposed to more in touch with it...
There are some dangers with spirituality and meditation. People should be aware that you are playing games with your own perceptions, with reality, with your mind. To varying degrees you may become more likely to take on new beliefs in a state where you are either less aware and discerning, or perhaps just confused by a new experience that you can't process on your own...
For myself, I'd almost rather just sit and meditate and put absolutely NO descriptions, religious connotations or other mental constructs onto what it is that happens in these times.
And Brad Warner says:
The general public doesn’t really have a clue as to what a Zen teacher is. So the model they usually chose to base their assumptions about what a Zen teacher ought to be is that of a religious instructor...
And so the idea has come down to us a hundred and some years later that Zen is a religion. I’m aware that there has been considerable debate about this. But mostly the debate has been framed in terms of the question: “Is Zen a religion or a philosophy?” I used to side with the faction that said it was a philosophy. But I’m not so sure this is even the right question anymore.
It has occurred to me lately that Zen is not a religion or a philosophy, but might better be seen as a form of art.
I side with the "Zen Buddhism is a religion" folks; if a religion is not first and foremost a set of behaviors to which one applies skill, regardless of institutions, deities, and funny clothes, then what good is it?
For medical benefits? That seems somewhat unnatural in the same sense that people in armies don't fight and die for their country, they fight and die for their brothers and sisters so they may live.
Furthermore, if your practice is only on your cushion, it's not even like an artificial flavor versus the real flavor. You have a verisimilitude of practice, sometimes. But it's like having the keys to a Ferrari but only driving it out of the garage and into the driveway and claiming you "drive" a Ferrari. No, this needs to be done as much as one can, in every situation. And only you can be there to do that, and when you're there doing that, there is no brainwashing.
Now on to the bigger question, as raised by Gniz: having great faith and great doubt does not mean great faith is invested in your teacher and great doubt is invested in everything else that might run counter to what your teacher says. In American Rinzai temples in the tradition established by Soen Shaku we chant from the Mahaparinirvana sutra:
Atta DipaViharathaAtta SaranaAnana SaranaDhamma DipaDhamma SaranaAnana Sarana
You are the light
Rely on yourself
Do not rely on others
The Dharma is light
Rely on the Dharma
Do not rely on others
Any teacher which ain't teaching this, to get slightly fundie about it, is not teaching a Buddhism as taught by Shakyamuni.
Suspension of opinions includes opinions about the teacher. If he's on a pedestal you're light years away. And if you can't see your closeness to Pat Robertson, Mother Teresa, Pol Pot, Ben Stein, Sean Hannity and Michael Moore, you're not there yet either.
Regardless of what an unscrupulous teacher might say, and they are there, in this practice you cannot check your brains at the door.
This is embedded in the structure of the most fundamental of Zen koans; e.g., Case 39 (see here for another translation and commentary) of the Mumonkan says:
CASE 39. UN-MON AND TRAP INTO WORDSAs soon as a monk stated Un-mon, "The radiance of the Buddha quietly and restlessly illuminates the whole universe", Un-mon asked him, "Are these you are reciting not the words of Chosetzu Shusai?" The monk replied, "Yes, they are." Un-mon said, "You are trapped in words!" Afterwards Shishin brought up the matter once more and said, "Tell me, how was the monk trapped in words?"Mumon's Comments:A fish meets the fishhook in a rapid stream,
If you are able to grasp Un-mon's unapproachable accomplishments and follow through the monk's corruption (of being trapped into words), you will be the leader of humans and Devas. If not, you cannot even save yourself.
Being too greedy for the bait, the fish wants to bite.
Once his mouth widely opens,
His life is already lost.
Yunmen (Ummon) is saying the student is "trapped in words" or has "misspoken" in response to his student quoting another's poem. The context as to why the student quoted the poem is not given but clearly what was expected here was the student's expression of his understanding. That's why you can read all the koan commentaries you want til the cows come home (just when do they come home?) but a reputable teacher won't confirm anything unless it's truly, authentically your expression of your understanding, and if he doesn't, you're going to understand anyway.
So no, Gniz, nothing to worry about. Just keep going.