Our six senses, physical inputs and mathematical
underpinnings v1.5
We have been educated and not only taught to praise absolute scales and values as better than relative things.
No wondering the reasoning that our sensations are based on absolute metrics and thus are quite stable, quantifiable and predictable, was one of the main pillars to the claims of the scientific status of behavioural and psychological studies. After all our relationship with the outside world should be based on absolute scales of reference, right? Not necessarily. So, let us forget for a while academic textbooks, googling and common sense and look again to our sensorial skills.
We all have 6 senses responding to 4 main physical sources or inputs
Inputs Senses
light visual
gravity vestibular
pressure auditory
tactile
molecules olfactory
gustative
And for each sense there are candidate inputs too weak to be sensed up to others that would at least be painful or even destroy sensorial components. From a firefly against a bright moonlight background, to the direct sighting of the Sun, for example. All this in a continuum of physical magnitudes and sensorial levels:
minimum input inputs for everyday life maximum input
to fire a sensation that can be processed
___________|_______________________________________________________________________|____________
absolute threshold relative thresholds terminal threshold
Absolute and terminal thresholds are useful for health and safety. An absolute threshold is also praised by basic researchers because it allows a clear data cut, “all” or “nothing”. Other than that absolute and terminal thresholds are irrelevant. For understanding real life of humans and animals the relative ones are key: what is bigger or approaching or tastier, etc. And there is plenty of evidence that we are continuously calibrating each sense relative answer as we are adjusting the interplay between our sensations from different sources.
An empirical example of relative thresholds of sound loudness could be found in a previous post. Moreover, the signal to noise ratios (SNR) are quite often critical in our every day life. When we are involved in a conversation the ratio between the voice of our partner , the signal, and the surrounding noise is much more relevant than the absolute values of each of the sounds and noises we are hearing. Likewise, ratios are routinely used as main parameters in several scientific and engineering fields. Including the specification and calibration of artificial sensors or transducers for light, sound, pressure, etc.
Sound pressure waves in, electrical signals out
In fact, absolute quantities are often nor known nor needed to compute relative values. Moreover, it might be worth noting that non-absolute values, but the difference between magnitudes are also quite relevant in many natural phenomena. And, one of the seminal contributions of H. Weyl (1885-1955) for the modern physics was exactly on demonstrating (gauge invariance) that some physical relative quantities do not change regardless of the underlying absolute magnitudes; therefore, robust models in physics as in quantum mechanics, could be built without a reference scale. And our senses do rely in biological transducers adapted to the surrounding physical sources of stimulation.
In short, our senses are evolutionary refined to extract meaningful information from environmental stimulation. Also, each individual is constantly testing and adjusting his sensorial sensitivity. And more than just a coincidence or analogy all these facts might indicate a homologous mathematical ground of relative magnitudes, both in physical inputs and the senses we have to gather them.
