JoeTheJuggler
Penultimate Amazing
- Joined
- Jun 7, 2006
- Messages
- 27,766
That's not logical at all.In space there is no sound signal to be perceived, but there is gravity. Which the crew of the ISS don't "sense". Because humans don't have any native sense for gravity, if humans could "directly sense gravity", the ISS crew could do so as well. But they cannot, which disproves the assertion. Yawn...
Since we can't see a single photon, does it follow that we can't directly sense light? What about sound below a certain decibel level? If I can't hear that, does it follow that I can't directly sense sound?
I'm sure there are minute changes in temperature that I can't sense. Does it follow that I can't sense changes in temperature?
Humans can directly sense gravity and linear acceleration. I showed you the statement from Wiki's article on otoliths. Now I'll quote my old A & P textbook (Human Anatomy & Physiology, 3rd Ed. Elaine M. Marieb):
There's a lot more. I tried to trim it a bit.Transducing Gravity and Linear Acceleration Stimuli.
Let's look more closely at the "happenings" in the maculae that lead to sensory transduction. When your head starts or stops moving in a linear direction, inertia causes the otolithic membrane to slide backward or forward like a greased plate over the hair cells, bending the hairs.
<snip>
Likewise, when you nod your head or fall, the otoliths roll inferiorly, bending the hairs of the maculae in the saccules. When the hairs are bent toward the kinocilium, the hair cells are depolarized and step up their pace of neurotransmitter release. As a result, a faster stream of impulses is sent to the brain. When the hair cells are bent in the opposite direction, the receptors are hyperpolarized, and neurotransmitter release and impulse generation decline. In either case, the brain is informed of the changing position of the head in space.
<snip>
Thus, the maculae help us to maintain normal head position with respect to gravitational pull.
Gravity is a natural phenomenon, like radioactivity. But that says nothing about our senses for these. I don't get your point.
My point is that the following isn't accurate:
As I said, we can sense changes in linear acceleration and changes in the orientation of our head with respect to the center of mass of the Earth. We can directly sense gravity.We don't observe gravity. We observe that we are falling down when jumping from the roof.
And that the existence of gravity is not analogous to the existence of God. As I suspected, that was how this came up in this discussion--an attempt somehow to liken our "belief" in the existence of gravity to belief in the existence of God.