Sense Perception as a Way of Knowing:
For human beings, existence itself is that which is questionable (but why do we ask the “why”?). We experience our existence through our five senses: seeing, taste, touch, hearing and smell, but we still question whether or not there is something that is knowable in the world we experience. Human life, unlike the life of animals (or other entities such as chairs for that matter) is something with which humans must concern themselves. For the historicist thinkers, human being is in such a way as to be something that understands something like Being, and it does so with time as its standpoint. This is why there is such an emphasis on the social and historical contexts placed on your studies.
With sense perception as a way of knowing, it is human being that must be understood first. “Knowing” is one of the ways that human beings “are”. This basic state of our Being-in-the-world must be understood/interpreted first. Otherwise, it is the ‘world’, our ‘world’, that gets passed over and consequently our being -in- the- world; and, therefore, something essential about the Being of human beings is lost in this forgetfulness of the passing over. Why ‘knowing’ does this we will see shortly.
To be mindful of the world is to think about it in our everydayness: our lives at school, our social lives, those things about which we are concerned, and those things that matter to us in some way. These encounters are what make our human Being “come alive”. These ‘ready-to-hand’ entities/things or ‘equipment’ for writing, knitting, measuring and manipulating, for example, are entities that ‘are in order to allow human being to do something; they are not mere ‘things’, their being is ‘for the sake of’ something else’. Think of your current use of the computer, right now, at this particular moment. Furthermore, your computer, ‘equipment’, exists in a ‘totality of relationships’ that ultimately forms the web of your human being in the world. This web is the technological. Thus a computer is for researching and writing or for making social contacts that produce a sense of being alive for you and, by implication, for others. Human being is ‘in’ this world not as a ‘sailor in a ship’ — which he can leave — but ‘in’ in this sense is what human being is; what we are as human beings is our existence in the world; human being is therefore ‘spatial’. This ‘spatialness’ is experienced through sense perception as a way of knowing the world.
We become so caught up in our everyday dealings with the world that we don’t even notice them most of the time, except when something we need is missing or broken — then things are not ‘handy’ (the subway breaks down, for example); then the ‘concernment towards which’ we are oriented is disclosed and, in this way, the “‘world’ “announces itself”. The world is revealed: “in anything ready-to-hand the world is always ‘there'”. This world “does not get created for the first time by knowing it nor does it arise from some way in which the world acts upon a subject”. Rather, we, as human beings, encounter the world; it has ‘significance’ for us as human beings. This significance is what we call ‘experience’.
When we stop to consider or think about the computer, then it is. When we ‘know’ it in this way, the computer is present-at-hand, not ready-to-hand. How is it that I ‘grasp’ what this is? There is an intrinsic relationship between ‘human being’ and the world shown in the way we encounter things in a ready-to-hand way. We do not grasp things just theoretically or mentally but also physically and practically (the world ‘gives’ the things to us). We are not along-side things the way a wall is alongside a chair. The chair and wall never ‘touch’, but a human being encounters the chair, touches the texture of the wall. It does not simply ‘know’ the thing as an isolated subject meeting up against an isolated object. In this latter way of knowing, we have to think of knowledge as a ‘grasping’ or ‘getting it’. We want to consider knowing [as] …an activity carried out in a particular context, for particular reasons… and so knowing is one aspect in the complex web of activities that make up a culture and a society. In this way of knowing, the ‘world’ is still there and is present-at-hand; we are ‘tarrying-along-side’ but still in the mode of ‘in-order-to’. We are free to choose to exist as human beings in either an authentic or an inauthentic way in this ‘tarrying-along-side’.
Historical Background: Descartes Thinking on Sense Perception:
In our discussions of Reason as a WOK, we examined Descartes’ cogito ergo sum. Descartes began his “meditations” by doubting and examining the evidence of his senses. Descartes’ analysis of the ‘thinghood’ of a honeycomb of wax in the Second Meditation culminates in the understanding of it as a res extensa — a substance extended in space that is grasped “by the mind alone”. When everything else it taken away — smell, feel, colour, the sound it makes when struck — a clear and distinct idea of its extension remains. He can come to this understanding because he is, in essence, a ‘thinking thing’ or res cogitans: “Even bodies are not strictly perceivable by the senses or the faculty of the imagination but by the intellect alone and that this perception derives not from being touched or seen but from their being understood” [Descartes, Rene Meditations on First Philosophy. Trans J Cottingham Cambridge University Press 1986, Second Meditation p 22].
This mind is wholly distinct from the body for Descartes. Even though he cannot be “separated from [his] body as [he] could from other bodies”, it is a substance in which the incorporeal mind subsists. The mind then is of his essence (what he is as a human being) while the body is a mechanism that somehow is connected to the mind. The body can of course give him information, but this may be false; if my limb is cut off, I may still have the sensation of pain in it — this, according to Descartes, is more evidence of the unreliability of sensory information and a further reason to make a clear distinction between mind and body. In Descartes’ ‘world’ we can therefore, without doubt, have a res cogitans (a thinking thing) and a res extensa (a thing extended in space). The apprehension of the thing’s extension is space in its ‘calculability’ through mathematics, the reasoning of the mind.
A substance, which is a res extensa, — Descartes in the Principia Philosophiae — is “an entity which is in such a way that it needs no other entity in order to be”. And there are two kinds of substance in the Cartesian world (as we have seen), a res cogitans and a res extensa. What we now have are two ‘present-at-hand’ entities in isolation alongside each other.
When all we have is isolated objects, then the ‘world’ remains hidden and so the being of human beings as Being-in-the-world gets passed over. Even Descartes himself needs God, ‘who is no deceiver’ to put clear and distinct ideas about entities into his mind in order for him not to doubt that they exist. But, now that he has found the foundation of knowledge in the incorporeal mind, Descartes can also explain the possibility of the existence of objects through mathematics and the mathematical.
Descartes begins his Sixth Meditation with, “It remains for me to examine whether material things exist. And at least I know they are capable of existing, in so far as they are the subject matter of pure mathematics, since I perceive them clearly and distinctly”. [Descartes, Rene Meditations on First Philosophy. Trans J Cottingham Cambridge University Press 1986 p 50] In a Cartesian world “that which enduringly remains, really is. This is the sort of thing which mathematics knows. That which is accessible in an entity through mathematics makes up its Being”. [Heidegger Being and Time. We need to recall “mathematics” here means what is “learnable” and what is “teachable”.]
The Cartesian world consists then of these entities which have their kind of being prescribed for them by the human mind. Two present-at-hand entities (such as the thinking being and extended things) cannot be related to each other. We can look at the example of Descartes’ explanation of the attribute of ‘hardness’ as ‘resistance’. Resistance amounts to no more than not yielding place, not changing location. In this way the experience of sensory perception is obliterated and things cannot be then grasped in their Being; what we have instead is two res extensa side-by-side, related to each other by means of mathematical calculation. But “hardness and resistance do not show themselves at all unless an entity has the kind of being which human beings -or at least something living — possesses”. ‘Hardness’ is something that human being encounters in how it experiences the object; hardness is disclosed to human beings in this encountering.
For Descartes, space is a matter of abstract mathematical coordinates and calculations in which things are located and move about; in what we are considering here, space is how human beings experience things. Things are ‘near’ or ‘close-by’ according to what a human being is concerned with at any one time. The pair of glasses on our nose can be considered further away than the object in the ‘distance’ that we want to give consideration to in some way.
Space and spatiality are thus neither in the subject nor in the world, but rather disclosed by human being in its disclosure of the world. It is this ‘disclosure’ of the world that readiness to hand provides. In disclosure, the world is revealed or unveiled (but there already) by human being. In the Cartesian analysis, the world would have to be ‘added on’ to the life of humans, in the way that the body is somehow tacked on to the mind of the human being. In Descartes’ analysis, objects are primarily encountered in a present-at-hand or in an isolated, decontextualized way and the ‘totality of relationships’ that make up the world of human being is not actually encountered and therefore the Being of human beings is not encountered. This lack of ‘world’ is what is lacking in current conceptions of artificial intelligence: its coldness was already presaged in the writings of Descartes, and its aspiration is the flowering of the essence of the Cartesian view of things. AI is what we call “cybernetics”.
The world for Human being is not a series of objects that we can come to know but a web of socially or culturally constituted concernments within which entities can appear as the particular type of object that they are and which must be disclosed in advance of any particular encounter with an object. The example of learning to use the computer — it is in this experience that things such as hardware or software applications or a command instruction can appear as the things they are. Eventually, all these things become inconspicuous as we become absorbed in them and we don’t notice our ‘world’ or the ‘worldhood of the world’. This is why the world tends to get passed over and why priority tends to be afforded to ‘knowing’ as it seems almost more obvious to us. We experience our being in the world as a desire to change the world in the forgetfulness of what is already present.
It is important to emphasize again that it is not that the present-at-hand or decontextualized mode of encountering the world is not a valid one; rather it is a deficient mode and, as such, is not the primary mode we should use in encountering the world. It is deficient in that if this is its only — or at least primary — mode, it cannot account for the ready-to-hand as a ‘grasping’ or of constituting an ‘in-order-to’ and thereby misses both the world as ‘world for human being’ and the human being as a being whose being is an issue for it, i.e. the possibilities it has through practical engagement with the world. The world is experienced as shadows and our ‘thinking’ is a one-track thinking.
Berkeley’s “Esse est percipi”:
George Berkeley (1685-1763), a British philosopher and Anglican bishop, attempted to show that there no such thing as matter. All that could be said to exist were sense perceptions which vary according to which observer is making the observation, the position of the observer, and the circumstances of the observation (such as the amount of light). Such a variety of contradictory sense perceptions (the thing cannot be of different colours, sizes and shapes at the same time) suggests there could not be a real thing there but only a set of sense perceptions (sensations) with no continuing identity. Berkeley suggested that these sense perceptions existed only in the mind; they were mental entities only and could only exist when an observation is made. He considered “To be, is to be perceived” (“esse est percipi”) and that no world existed beyond our sense perceptions.
From Berkeley’s position, what we see varies with the sensory apparatus used to make the observation and the conditions within which the observation is made. If one changes the position of the observer, the shape and colour of things change; if a different sensory apparatus is used, there may not be any colours at all or there may be additional colours that humans are not aware of through their ordinary sense perception. What is seen, heard, smelled, tasted and touched varies with the sensory apparatus used and the conditions under which they operate.
Sounds are vibrations in the air, but if there is no air, for example in outer space, no sounds can be heard (the catch line in Ridley Scott’s film Alien: “In space, no one can hear you scream”). The ability of dogs to detect smells and sounds not perceivable by human beings shows that different sensory apparatus will produce different sense data. Tastes appear to vary from person to person and from species to species. What is poisonous to one species may be food for another. Touch varies with the conditions available, for example a cold hand placed in cold (but less cold than the hand) water, will feel warm. The feelings obtained by touch also vary with the part of the body used for the touch as some parts of the body are more sensitive than others. If the sensory apparatus or the conditions of the observation are changed, then different sensations will be produced. This suggests the sensory process involves a relationship between the sensory apparatus, the conditions of observation and whatever, if anything is out there. If any of these are altered different sensations will be produced.
Berkeley’s interpretation is that there is no such thing as matter and that sense perceptions are mental entities only. In order to claim there is no such thing as matter, it would be necessary in some way to go beyond our sense perceptions to see whether matter exists or not. This is something we are not able to do. Equally the claim that what we see (notice that this is only is only dealing with sense perceptions, not with what can be known) are only mental entities is doubtful, when what we see seems to involve a relationship between the sensory apparatus, the conditions of observation and whatever, if anything is out there.
Kant’s Response to Berkeley:
Whatever is observed when an observation takes place is sensations. Our measuring devices require ‘sensations’ in order to make their measurements.
Given that the sensations change if different sensory apparatus are used to make the observation suggests there is no single objective reality available to us other than that which can be attained through the mathematical. It may be that such a reality exists, but we can never know it through our sensory apparatus or sense perception. The “what” or the “how” of sense perception does not matter: it is not “knowledge” until it is placed into some kind of mathematical “frame”. Berkeley suggested there was nothing beyond our sense perceptions, while Kant suggested there was “noumena” or the “thing in itself” and stressed the unknowability of the noumena. In effect, Berkeley claimed matter did not exist (i.e. nothing beyond perception i.e. esse est percipi) “to be is to be perceived”, thus an ontological matter, while Kant considered it to be an epistemological matter i.e. we have no way of knowing what is beyond perception except our own “mathematical” projections. This is why the sciences must report their results in mathematical language. The reason as a way of knowing, the essence of the mathematical, is what is ‘reported’.
Berkeley’s position, while rationally consistent, is not psychologically satisfying as an ontological statement and inadequate as an epistemological statement. Our perceptions are not primarily bundles of colours or sounds; what we perceive is already perceived as “some thing,” the accent here being on the word ‘thing’, and therefore it is doubtful whether we gain anything by taking the perceptions instead of the things as the ultimate elements of reality.
If there was nothing beyond perception, perceivers would always, subject to some variation caused by the conditions of observation, perceive the same sensations. Nothing is uniform with sense perception as a way of knowing, and if such uniformity were present, it would tend to produce the same sensations wherever and whenever one looked, while our sensations vary considerably. The uniformity of what is is provided by the modern sense of the mathematical: the uniformity of number grasping the uniformity of matter. Time and space are conceived as uniform mathematical units. The particularity of the categories of the things, their colours, etc. is passed over. (See the unit on Reason as a WOK).
Sensations will vary if you change any of:
- the observer or sensory apparatus used (which remains a part of the observer); or
- the conditions of the observation; or
- the point in space and time from which the observation is taking place
The relationship between the observer, the conditions of observation, and the thing observed will “give” different sensations if you alter any of the observer, the conditions of observation, or the observed.
For Kant, it is necessary to distinguish between phenomena and noumena. The noumena, due to our inability to get past perception, are something we cannot know about: we cannot know “Nature”, but only “Nature” exposed to our method of questioning. What we can be certain of is the “I think”. It is phenomena that constitute “the world” in which we live. Phenomena come in an infinite number of forms and are produced by the inter-relationship of the perceivers’ sensory apparatus, the conditions of observation and whatever, if anything, that lies beyond perception. Phenomena cannot exist without an observation being made. Noumena, according to Kant, exist independently of observers. When one talks about an observer dependant universe, it is phenomena that one is talking about. (Remember that for the Greeks, “phenomena” are those things that are “made” by human beings. In describing only that which is “knowable” as those “things” which we ourselves “make”, then we have an understanding of what Kant meant when he said: “The mind makes the object”.)
The idea of noumena and our inability to perceive the “real world” is consistent with other philosophical theories such as Popper’s falsificationism, Hume’s analysis of cause and effect, and the problem of induction. Each remains embedded and indebted to the history of metaphysics in the West.
Popper’s falsificationism suggested a scientific theory could never be proved correct but could only be falsified by observations that contradicted the theory. This is because while we can observe phenomena that contradict the theory, we can never look beyond or behind the theory to check whether it was correct as this would involve “observing” the noumena (the mathematical propositions), which is impossible. They are part of the subjectum, not the objectum. They are the looking itself, and the looking cannot give an account of itself within its own look.
David Hume noted that we can never prove cause and effect; all we can do is observe the co-relation of phenomena. We can observe one billiard ball hitting another and the second ball being set in motion, but we can never prove the second ball was set in motion by the first. We can never prove a necessary connection between the first ball hitting the second ball and the second ball being set in motion. We can merely show the one event, (the first ball hitting the second) was followed by the second ball being set in motion. The inability to show the first ball caused the second ball to move is because we can only see the phenomena and we cannot see the noumena.
The problem of induction (inductive logic) is also consistent with the idea of noumena. With induction all we have is repeated examples of the same phenomena in a particular situation, but we can never be certain that in the same situation the phenomena will always be repeated. This is because we are unable to see behind the phenomena to see the cause of the phenomena. This would involve observing the noumena, which cannot be done.
Sense perception and Quantum Physics:
The uncertainty principle of quantum mechanics, determined by Werner Heisenberg, concerns the impossibility of obtaining precise measurements of certain pairs of properties of quantum “things”. The example usually given is that of the position (space) and momentum (time) of an electron, the principle stating the more precisely we try to measure the position of an electron the less precisely we will be able to measure its momentum. The principle is sometimes explained on the basis that the only way we can observe an electron’s position is by bouncing photons off it that will tell us the electron’s position. However, the collision between the photon and the electron will disturb the electron’s momentum making it impossible to measure both position and momentum at the same time. This is called the Copenhagen Interpretation of quantum physics.
This, however, is not the full story. The mathematics of quantum theory makes it clear that electrons and other quantum entities simply do not have a precise position and a precise momentum. They may have a precise position but then they will not have any knowable momentum at all, or they may have momentum, but their position will not be knowable. (Gribben, 1984, 157). By observing the quantum entity’s position (space), we observe it as a particle, by observing its momentum (time) we see it as a wave. This means we may measure the quantum entity as a particle and observe its position or as a wave, but it is not possible to see it as a wave and particle at the same time. Both the wave view and the particle view are necessary to understand the quantum world. They can be seen as different sides of the same coin. Any experiment designed to show waves, will show waves, any experiment designed to show particles will show particles, however no experiment will be able to show both wave and particle pictures of the quantum world at the same time.
The consequence of the Copenhagen Interpretation is that the observer plays a critical role in determining how the world is. The behaviour of atoms, electrons and light depend on whether an observation is being made. If it is, then the wave function collapses and they behave as particles. If no observation is made, then electrons, atoms and light behave as waves.
Schrodinger’s Cat and the Paradox of QM on the Macro Level of Perception:
A similar problem at the macroscopic level is revealed by the puzzle of Schrodinger’s cat. Quantum mechanical effects are assumed to apply at macroscopic level as macroscopic objects are made up of quantum entities. Schrodinger’s cat is placed in a chamber with a radioactive substance of which there is a 50% chance one of its atoms will have decayed within an hour. Should the atom decay a Geiger counter will detect this event and cause a hammer to break a flask containing a poisonous gas and so kill the cat.
The common sense view is that after one hour the cat will be either alive or dead. However, the Copenhagen interpretation considers that since the Geiger counter is made up of quantum entities it is subject to the quantum mechanical rules and does not exist until an observation collapses its wave function. It is not until an observer opens the chamber that the wave function of the whole system collapses and the atom may or may not decay, the Geiger counter may or may not detect the radiation, and the hammer may or may not break the flask, and the gas may or may not kill the cat.
Before the observer opens the chamber, the Copenhagen interpretation considered the cat to be neither alive nor dead but to be in suspended animation or a superposition of states. Alternatively, the cat can be considered to be both alive and dead at the same time. Obviously a cat at any one time must be either dead or alive and it certainly cannot be both dead and alive. So, what is happening in the box before it is opened and the wave function collapses? One view is that the cat itself is able to collapse the wave function so the cat is never both alive or dead or in a superposition of states. If there was a human, sometimes called Wigner’s friend, in the box instead of the cat no doubt he or she will collapse the wave function. After an hour when we open the box, Wigner’s friend will either report nothing has happened or we will find the corpse of Wigner’s friend. There is no case of a superposition of states here, but to a human outside the box the superposition of states remains.
If the human opening the box is not actually being observed, if for example the building was sealed off to protect the experiment, then his or her wave function will not have collapsed. To the people outside the building, everything within the building will be in a superposition of states and this situation continues in an infinite regression. Is anyone observing the planet earth to collapse its wave function? Possibly any conscious being will be able to collapse its own wave function, in effect to be self-actualising and to bring itself into existence.
The Schrodinger’s cat paradox is designed to show how ridiculous quantum theory is when applied to the macro-world or the “common sense” world (and Heisenberg has said he spent many nights wandering alone wondering whether the universe was as crazy as it appeared in his experiments). Yet as entities in the macro-world are all made up of quantum entities it would appear that quantum theory must apply in the macro-world. How can a macro entity, like a cat, exist if the quantum entities that make up the cat do not exist? The ridiculousness (and the consequences of arrogance and stupidity) of applying quantum theory to the macro-world was seen in the risk analysis that banks’ “number crunchers” made prior to the collapse of the banking system in 2008 where the probability function of quantum mathematics was used in risk analysis for derivative investments.
Furthermore in the “common sense” world, the phenomenon of superconductivity shows quantum effects operating in the macro world. It is possible to observe quantum effects on macro level instruments such as superconductor rings which may be several centimetres across and are of course made up of a vast number of atoms. This means it is not possible to say the rules of quantum mechanics apply only in the quantum world. (Davies, 1980, 128-129; Lindley, 1997, 176). It appears the same set of rules should apply to both the macro and quantum worlds and the rules that should apply are the quantum rules. So macro level measuring devices such as Geiger counters, bubble chambers, photographic plates, cats and humans should not exist until they are observed.
If one accepts the standard Copenhagen view of the quantum world, quantum entities do not exist until they are observed. If one accepts the standard common sense view of the macro-world, things continue to exist regardless of whether they are being observed. An attempt to accept both views would mean there must be a level where the rules of quantum theory cease to apply and the rules of classical physics begin to apply. It is however hard to pinpoint exactly where this level is and why it should apply. The case is that the laws of classical physics apply to the macro world, but they lack precision. They are not “knowledge” in the traditional way of understanding what “knowledge” is i.e. a certainty about what something is. Kant’s a priori conditions of time and space are shown not to exist as such in the quantum world.