It is ideas, forms, that we doubt when we doubt because it is by forms/ideas that we realize what before is only phenomena...
But phenomena "before" are merely more forms/ideas.
Scent is one of those qualities always attached to its cause as in: Smells like a rose, or stinks like crap
Have you never smelled something you couldn't identify?
I worked in a kindergarten once, and one day I caught a whiff of something I thought was hot food cooking, but when I got closer I was able to identify the smell. It was coming from a used diaper that someone was changing off an infant.
It seems to me you think that most of our reality is centered around vision, or that the major part of a human being's awareness is visual awareness. You say, "our ears are not much".
I think that audio impressions make up at least as much of the total awareness as visual impressions. There are many things that are better done by ear. Vision only covers half your surroundings at any time. Hearing covers everywhere, even surfaces we cannot see through.
To reply to the op; those who continually question their thoughts and senses are at a distinct disadvantage since they would be better served using their thoughts and senses to observe their environments for signs requiring attention
I believe that it is possible to act on one's own thoughts and sense inputs and still question these things. I agree that it doesn't serve to become mired in reflection, but that does not mean we have to just pick a belief and stick with it. I think that those who do not continually question their beliefs and their perspective on reality are at a disadvantage, because they can become hateful and mired in their doctrine as the world gradually passes beyond it. As always, a middle ground is probably the way to go. We must trust enough to act, but question enough to learn.
I suppose I would have to revert to the earliest use of the word: Pehenomenon to say with certainty, but what I gather from Heidegger and what I have read of others, phenomonon does not raise to the level of form... True forms and ideas are of the physical world, and experience of infinites is always phenomenal...
What I say of eyes is only what Aristotle says of eyes, that sight is the sense we would choose least to live without since we gain so much knowledge of life through our eyes...
Whether we are active, or reactive by nature, we must admit that formal understanding, like formal behavior limits our options... If I live in a society that has nothing better to rely upon than faith in God, then I would not challenge them, as this would endanger me, but I would hedge my bets with some science, and most of all: Alert Attention... People go down with the ships of their societies because they cannot break free, or think free of their social forms... Individualism has been at once the greatest success and most terrible failures since the middle ages... It is drummed into us, and expected, but little found except in the usual locations of art and criminality, what ever the difference between those two may be... My point is, that humanity has survived to the present through cooperation, and that sin, like individualism rise with civilization; but that when civilizations fall they often take all down with them because too few have what it takes to scoot before things get really bad, and so weather the storm of social change...The best attitude to have is one of alertness, and mild anxiety, that learns all, and accepts all, is tolerant and embracing of all that works and is respectful... If you know that history is the story of changing social forms, then you will be prepared for it... The future is achieved by those who can best visualize it, and communicate it to others...