According to the following sources, sensations originate after association, so what happens before it?

Wordnet - the faculty through which the external world is apprehended

Etymology - 1610s, "a reaction to external stimulation of the sense organs," from French sensation (14c.) and directly from Medieval Latin sensationem (nominative sensatio), from Late Latin sensatus "endowed with sense, sensible," from Latin sensus "feeling" (see sense (n.)). Meaning "state of shock, surprise, in a community" first recorded 1779.

and sense means: Application to any one of the external or outward senses (touch, sight, hearing, etc.) in English first recorded 1520s. Meaning "that which is wise" is from c. 1600. Meaning "capacity for perception and appreciation" is from c. 1600 (as in sense of humor, attested by 1783, sense of shame, 1640s).

I've always understood the process of [sense organs receive stimuli and transfer that 'information' to the brain for processing] as Sensing, and the information conveyed is a Sensation. In other words, sensations happened before getting to the brain, whereas the brain makes sense of them by association. What 'sense' the mind makes of it is a perception, which Association causes, not sensing, which happens beforehand. The word 'information' is being used loosely, since whatever's transmitted from our eyes and ears are different and have no meaning yet, with this understanding of sensations.

So if I've been wrong all of this time, then what is the process called that I've wrongly called sensations? The reason it's important is the need to distinguish between ___ being shared the same by two or more people but perceived by them differently. I have filled in that blank with the word sense, believing that happens before association, but if it happens with association, I'm using the wrong words.

Used in a sentence, "before we can sense what we see, we must _____ first, which includes light received by our eyes and translated into something our minds can make sense of.

4 Answers 4


This question has no answer from a philosophical perspective: sensation is the interface to the external world, and the knowledge, not only of such external world (which cannot be necessarily accepted to exist), but also of how the sense interacts with that external entity, depends completely on such interface.

In consequence, any statement about what happens there is necessarily a speculation. Answering the question is equivalent to using an electronic thermometer to understand that the macroscopic incoming electric signal was produced by a dynamic of microscopic molecular interactions involving kinetic energy and other thermodynamic quantities.

On one hand, a particular sense is an active and a passive system at the same time. If God is on the other side of the senses (George Berkeley's thesis), then it is first, activated, after a divine command, and second, it produces what we perceive. So, "before we can sense what we see, we must wait for God's command first". Equivalent answers would raise for solipsism, idealism, etc.

On the other hand, all the information that we could get about the source of sensation is precisely that which is provided by the very sensation. So, what "occurs before we can sense what we see" can only be philosophical speculation, and will depend on the approach of the discipline/field/philosophical school. For example, in scientific realism, the probable answer is "before we can sense what we see, our eyes must physically interact with photons first".


Well, it depends on the context. The question is whether "sensation" is something that occurs in sensory receptors and peripheral nerves, or in the brain/mind.

In psychology these terms may mean what you said, i.e. "sensation" can refer to things happening in sensory receptors and nerves outside the brain. For example, from this article:

When sensory information is detected by a sensory receptor, sensation has occurred. For example, light that enters the eye causes chemical changes in cells that line the back of the eye.

However, here's an alternative take, from this book about the psychology of perception:

deciding what is sensation is what is perception is not always obvious, or even that useful ... this book takes the position that calling some processes sensation and others perception doesn't add anything to our understanding of how our sensory experiences are created, so the term perception is used almost exclusively throughout this book. Perhaps the main reason not to use the term sensation is that, with the exception of papers on the history of perception research (Gilchrist, 2012), the term sensation appears only rarely in modern research papers ... whereas the term perception is extremely common. Despite the fact that introductory psychology books may distinguish between sensation and perception, most perception researchers don't make this distinction.

Dictionaries tend to have definitions, such as this one, which characterize sensation as a mental process:

a mental process (such as seeing, hearing, or smelling) resulting from the immediate external stimulation of a sense organ often as distinguished from a conscious awareness of the sensory process

And we might often say things like, "I feel a warm sensation" - indicating that sensation is something that is felt subjectively, i.e. in the brain. Also, a paralyzed person might say that they have no sensation below the waist, even though the sensory receptors are still there and still being stimulated. This again indicates that in common use "sensation" is something in the mind, not at the sensory receptor.

So we might say that the common usage of the word and the usage in psychology tend to be different, and if you want to be philosophically precise, it would be a good idea to make clear which definition you're talking about, or perhaps avoid the word "sensation" altogether.

My suggestion would be to say:

  • The stimulation of the sensory organ is referred to as "stimulation of the sensory organ" or "stimulation of the sense receptors."
  • The information sent along the nerves from the sensory organ towards the brain is "sense data" or "sensory information."
  • When the sense data arrives in the brain, and has been processed enough to reach conscious awareness, it's a "perception."

Transduction or Apprehension are apparently the words I'm searching for....

Thanks to a door opened by Jo Wehler above regarding Psychophysics, I discovered several steps along the way, from how different disciplines refer to stimulus and the way they are received (receptors), to the TRANSDUCTION and transmission of 'sense data' to the brain for making sense of things (association).

Here's how it's described elsewhere: "During sensation, sense organs collect various stimuli (such as a sound or smell) for transduction, meaning transformation into a form that can be understood by the brain. Sensation and perception are fundamental to nearly every aspect of an organism's cognition, behavior and thought."

Notice how this description separates sensation from perception, the way I've always understood it. The phrase, "make sense of it," includes the verb, 'make.' That either includes unconscious calculations or conscious choices, but either way, it's not what the sense organs received, transduced or transmitted, it's what was perceived.

One of my frustrations is with the way different disciplines use the same words--I appreciate different applications of a word, but not changing the fundamentals of it. In that respect, this definition fits all disciplines, including psychology, physics, economics...and philosophy too. From a philosophical perspective, all reactions require sensations, from the physical energy caused by mass that is not sensed in a common sense of the word (moving rocks pushing stationary ones upon impact), to the behavior of living organisms that is traditionally recognized. This is why this meaning is so important to me philosophically, because it is the first step in all motion.

Therefore, Sensations include receiving, transducing and transmitting stimuli, whereas Perception begins with making sense of Sensations...the way I understand it.

Apprehend is one of those words with conflicting meanings: here's what wordnet provides:

(v) grok, get the picture, comprehend, savvy, dig, grasp, compass, apprehend (get the meaning of something) "Do you comprehend the meaning of this letter?" (v) collar, nail, apprehend, arrest, pick up, nab, cop (take into custody) "the police nabbed the suspected criminals" (v) apprehend, quail at (anticipate with dread or anxiety)

But if you look to the etymology, you discover it's plainly to seize:

late 14c., "grasp with the senses or mind;" early 15c. as "grasp, take hold of" physically, from Latin apprehendere "to take hold of, grasp," from ad "to" (see ad-) + prehendere "to seize" (from prae- "before;" see pre- + -hendere, from PIE root *ghend- "to seize, take"). Often "to hold in opinion but without positive certainty." "We 'apprehend' many truths which we do not 'comprehend'." [Richard Trench, "On the Study of Words," 1856].

So, the process from the moment stimuli contacts a sense organ, includes the mind 'seizing' it to make sense of it. I'm not sure that's true however, but instead, the sense data is sent whether our minds compel it or not! But from a complete systems perspective, the system's transmitting it from the sense organ to the 'making sense of it' organ (brain) is apprehension.


Your question relates to the domain of psychophysics.

The process you consider starts with stimuli received at the sensors. The stimuli are sent as sensations along the neurons to the sense specific areas of the brain. The sense specific areas process the sensations. The unconscious part of this processing is called perception, the conscious part is called apperception. The result of apperception is the meaning, which the sensations have for the individual person, often in form of associations.

As you write, the meaning of a given set of sensations can be different for different persons. Because the meaning results not only from the stimuli and sensations, but also from the previous experience of the person.

Accordingly, I would call „perception" resp. "apperception“ the process after reaching the sense specific areas of the brain. And the process before reaching the brain I would call „sensation“.

Note: I am not an expert on psychophysics, and welcome any correction and improvement by experts.

Edited after discussion with @Christopher

  • Oh but that is my understanding too! If you study the etymology of these words, they skip what you call "the process before reaching the brain,' and lump it in with "the process after reaching the sense specific areas of the brain." It's as if the words have not caught up with modern understanding...or my question asks, is that pre-"specific areas of the brain" step have a different word/term? Feb 25, 2022 at 23:28
  • As for psychophysics, until someone proves what's real, it's all philosophy to me. I agree that it is all physical when it begins with a physical sense organ, but there are more sense organs than physical, including conscious awareness. I differ in what you call perception, because the unconscious mind perceives too--the reason for the confusion is that we're only aware of the conscious kind, but any conclusion our minds produce is perception. And if there are more than physical sense organs, then the term I'm searching for applies to the non-physical ones too. Feb 25, 2022 at 23:36
  • @Christopher What about discriminating between "perception" as the unconscious process and "apperception" as the conscious process? Of course both denoting processes after the sensations have reached the sense specific areas of the brain. - Your first statement invites to a longer discussion. The statement could introduce a new question.
    – Jo Wehler
    Feb 25, 2022 at 23:49

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