Do molecules possess "smell" or is "smell" just a subjective sensation in our mind ?

Question

When a molecule impinges on a receptor on a nerve cell in our nose, the receptor recognizes the molecule by its shape. If the shape is 'right' the nerve cell fires and ultimately we experience a sensation of smell. But the molecule itself only has "shape" it has no "smell".

If you disagree, (ie if you think the molecule has BOTH "shape" and "smell" ) are you saying "shape of a molecule" and "smell of a molecule" are two distinct physical properties of a molecule that just magically go together? If that's not what you mean, please explain what you mean.

to The One Who Knows:
It certainly isn't true that every human experiences the same taste and smell sensations from a given substance. This is known because certain people experience NO sensation whatsoever from the same substance that other people do experience certain sensations from. So it is certainly not obvious that we all have the same sensations. Beyond this, it is simply impossible to verify (and thus meaningless to state) that all people have the same sensations. It might seem like a reasonable assumption, but to actually verify it experimentally is in fact impossible.
And another point, what about other animals other than man? I wouldn't imagine that a dung beetle has a similar smell sensation of dung as I do.

The point I am making is : All sensations are subjective products of a mind. They are not objectively existing features of the "outside" world.

Another example: The sense of pain.

When a sharp object is pressed to my skin I experience a sensation of pain. I hope it is perfectly clear that this "sensation of pain" is not a physical property possessed by the sharp object itself. Rather, the "sensation of pain" is a subjective sensation produced in my mind. And what is true for the "sensation of pain" is true of ALL sensations.

to Bekki : Although I agree that this isn't a science question, I disagree that it is just about "semantics" or "philosophy". It seems to me to be a question about actual natural phenomena ( the sensations I experience) to which science has no access.

Answer 1

I agree with the "shape" bit, however it is a bit of both. Based on most physiological tests, there are seven primary olfactory stimulants that have been found to discriminantly excite separate olfactory cells, ranging from ethereal to putrid. The intensity of the "smell" depends upon the concentration of receptors bound and the degree of excitation of the olfactory cells. Complex odors are the result of the concurrent stimulation of two or more olfactory receptors, implying that a single chemical my occupy more than one receptor site. That is "shape." "Smell" kicks in when your nervous system integrates the responses to determine the identity of the primary odor stimulus being recieved. As far as the WAY things smell however, may vary since genetics are a large determining factor here.

Answer 2

I agree with your first part and so need not justify anything about the second part. Taste and smell etc. are subjective reactions produced in our nervous systems by the molecules. But since the nervous systems are remarkably uniform in almost all human beings, the same substance tastes and smells the same to all people.

Answer 3

That smell is mostly a matter of brain processing is shown by the fact that many chemicals have a smell to some people but not for other people. The chemical is that same, but different people smell it differently. The same goes for taste, by the way. There is a genetic component to whether broccoli tastes bitter or not.

Answer 4

The shape is the property, the smell is what we make to the property. So with that, molecule don't necessarily have smell, but we observe the smell. It's like that cliché of the tree falling in the woods.

Answer 5

This is more a philosophy/semantics question than a science question. My view on it is that properties like yellowness and smelliness (and even shape) are assigned by people to physical phenomena. We say that photons are yellow if they stimulate certain cones in our eyes and their wavelengths can be measured in a certain range. We say that molecules are smelly if they trip certain receptors in our noses.

Answer 6

I don't know much about the smell of a molecule, but I do know that you're a complete douche bag.

Answer 7

A.both