Agnosticism requires the belief of the measurable facts in front of you. There is not evidence for a God. There is no evidence for there not being a God. It is the most logical position.
You can say that requires belief but it shows a misunderstanding of the word belief. Its like saying you believe you breath air. Or you believe you drink liquids. Or you believe in the gravity that attaches you to this planet.
That sort of belief with evidence is not the same as belief without evidence. It is logical to belief we breath because we can see and measure it. It is not logical to have exactly the same level of belief in something we do not know is there, we cannot see and we cannot measure.