20080528

principle of epistemic closure


Where P and Q are propositions, if we know that P, and know that P logically entails Q, we know that Q.


Sometimes said to support skepticism,
because if I know that, for example, I am reading this blog, and know that if I am reading this blog I am not merely dreaming that I am doing so, then (by the principle) I know that I am not merely dreaming I am reading this blog : but, it is alleged, I cannot know that I am not dreaming because even if I were, things would still appear just as they do.

Therefore, I cannot know that I am really reading this blog.

1 kommentar:

autho unknowd sa...

The notion of implication itself is understood here in terms of (necessary)
consequence. Thus P implies Q iff Q is a (necessary) consequence of P. This is to
be contrasted with the much narrower, purely formal or syntactic construal, better
called entailment, on which P entails Q in virtue of logical form alone.

Entailment will not concern us here. Unlike entailment, implication is not self-
sufficient since it typically requires further data (in the relevant semantic
networks), such as meaning postulates, conventions or theoretical assumptions, in
order to hold.

Thus, for example, whereas "3 + 2 = 5" entails "2 + 3 = 5" by
virtue of logical form, "A is a physical object" only implies "A has a spatio-
temporal location" when some appropriate meaning postulate or assumption about
the concept of physical object is also activated. When, therefore, S realizes and
accepts an implication, it should be understood that S does so relative to whatever it takes (meaning postulates, assumptions, guesses, etc.) to represent that
implication.

First, there is leaming. In the early stages of concept formation, one's first exposures to the instances of a concept are retained as ideas.
If, for some reason, the invariance required by the concept is not internalized, one
is left only with ideas. Then there is also the maturation of some mental
competence, a process which typically goes from ideatic to conceptual grasp. For
example, before a certain age, children can correctly judge some volume relations
but misjudge others. They have some idea of volume, fitting particular contexts,
but not yet the concept. We find a similar story in language leaming. In the
beginning and for a while, the meanings of many words are merely ideatic. The
leamer tends to use those words in sentences which mimic those which first
introduced him to the meanings in question. One cannot take risks with ideatic
meanings. In other words, one cannot vary the linguistic configurations at will
and still control a meaning, if that meaning is ideatic.

Quite frequently, ideas are also formed on a more adhoc basis. Suppose that I do not have the concept of quark, which is true, and so I decide to look for an explication in a science
magazine for laymen. I take a copy of EASY SCIENCE FOR HUMANISTS and
look at a few diagrams and simple explanations populated with such entities as
electric charges, hadrons, gluons, and the like, some of which I already understand
conceptually, others only ideatically. As a result, I form a specific and rather
poor idea of what a quark is. Do I have some idea of quarkness? I surely do. Do
I have the concept? I don't.

Finally, another notion I need is that of ideatic redescription. The elements
for it are already in place. What that article about quarks did for me was to
ideatically redescribe or recategorize the concept of quark in terms of other
concepts and ideas already available to me. This is, generally, how learning goes.
It is a particular ideatic redescription provided by that article that, until further
developments, is going to constitute my idea of quarks.

Consider, for example, the role inner speech plays in the following situation: The other day I arrived at my office and discovered that I had run out of coffee. Needless to say I was panic-stricken, but suddenly it occurred to me that I had put some new coffee in my bag the previous night, and I had brought my bag with me to the office. My stream of thought took the form of natural language sentences which went something like this "...oh no, there's no coffee. What will I do? Where will I get some? Damn! What a hassle, I'll have to get some. But I put some in my bag last night...". The final part of this thought was accompanied by a visual image of me placing coffee in my bag. It is difficult to determine whether the sentence caused the image, or whether the image caused the sentence; but I think that since the first part of the monologue was entirely vocal (no images), it is reasonable to assume that language played a dominant role in the thought process.

During the sensory-motor stage, which lasts from birth until about the age of 2, the infant's cognitive system starts off as being limited to motor reflexes. The child's thoughts are primitive and consist in the simple coordination of sensory information with bodily movements. According to Piaget, as development continues, the child eventually makes its first big jump in cognitive ability and acquires object permanence. This is the realization that objects continue to exist even when they are moved out of sight. Piaget observed that before reaching this stage of development, children act as if objects do not exist when they are not being perceived. A child may be very interested in looking at a toy, but if the toy is then hidden behind a piece of paper (while the child watches), the child will not move the paper to find the toy.

However, once the object permanence stage of development is reached (between 3 months and 1 year according to recent research), the child understands that objects continue to exist and will seek out hidden objects. For Piaget, object permanence is a crucial stage of development because it marks the beginning of symbolic thought. It is at this time that infants can hold concepts in mind and can start to consistently use specific words to represent specific objects. This leads to an explosion of symbolic language usage and the subsequent restructuring of thought processes that give rise to productive and systematic thinking.

It is quite easy to arrange for someone to experience the sensory non-epistemically. If the subject with a probe in his visual sensorium does not know what is exciting the electric impulse at the other end, he cannot attribute any epistemic interpretation to it. First, he may not even know that he has a probe in his brain. Secondly, he may know that he has but he does not know what it is connected to - perhaps, a photoelectric cell in another room, such that, if he did know, he could tell us when a light came on, or perhaps it is connected to a Geiger counter, so that he might be able to warn us of dangerous radiation, but he does not know this, and so the experience is quite non-epistemic. But one need not go to the trouble of probes. Fit a virtual-reality hood on someone's head while they are sleeping and, as they are waking up, unaware of what has happened to them, make the input to the screens an entirely random one produced by some computer such that all that is on the screens is a phantasmagoria of rapidly changing shapes and colours, which undoubtedly would be purely non-epistemic, devoid of knowledge.

For example, if I search through my wallet and see a five-dollar bill, this bill is an actual bill. I can see it with my eyes and I can touch it with my hands. My perception of the dollar bill is finite and limited in space and time.

By definition, I say that all concepts which can be perceived solely and exclusively via the five
physical senses are actual. These concepts are called “actual” because they are defining
situations based on one’s perception of its surrounding world.

For example, as much as I can see and touch the dollar bill from my wallet, as much as it looks opaque and filled of matter, I know from the basic principles of chemistry, and physics that the paper making up the dollar bill is not whole and opaque. In fact, if I place the dollar bill under a magnifying microscope, I would see more of its actual atomic structure, which would reveal more of its actual nature and some of its real nature. I would see that the bill was not entirely filled as it appears to my
physical senses. It therefore must be, that my visual perception of the dollar bill is limited to
the perception of the bill I form in my objective mind with my physical eyes.

Say for example that I consider next the walls in my room. All physical observation of the walls, would reveal that they are filled in and opaque entities. But yet, someone in the room adjacent to mine can hear my conversations as well as the sounds from the television in my room. The sound of my voice or from the television must therefore be able to go through the walls even though my
physical perception of the walls would seem to indicate otherwise. Here again, it must be that
my physical perception of the room is finite and limited to my physical senses and was I able
to magnify the wall, in a way similar to the case of the dollar bill, I would see more of its actual and some of its real nature.

The observations we can derive from the preceding paragraphs tend to lead us to the conclusion that our perception of our daily living may not be a complete depiction of all that exists around us. However, our physical perceptions may be limited, sometimes perhaps very severely so, by the limitations of our objective world. It is like looking at the sea and seeing that it is blue from afar only to discover that the water is of a different color as we come closer.

In fact, most if not all of what we experience on a daily basis is actual
as long as we are solely relying on the five physical senses to reach an interpretation of them. It
therefore begs questioning: If all we are experiencing on a daily basis is actual and limited, how
much of the real world around us are we missing on a continual basis? The answer is quite
simple; we are missing most of what is real if we are relying solely on the five physical senses.
In some sense, our daily living may be “somewhat illusionary” since we are only living actualities that are very limited in time and space by our acquired perception of our world.

A real concept is a concept of the psychic or psychological world. All of what can be perceived solely and exclusively via the subconscious and subjective sections of the mind is real. The subconscious section of the mind, which communicates to the brain via many glands, is non-
physical and infinite. Among the many glands being used, to serve as the bridge between the subconscious and objective minds, the pineal gland is the most important. Although the pineal gland is physical, it performs the essential function of filtering high vibratory energy from the
mind to the brain. In fact, energy from the mind is mostly of cosmic frequency (and above). It is the pineal gland that has the faculty and responsibility to relate this type of energy from the mind to the brain.

The pineal gland accomplishes this mission by lowering the frequency and vibration of the cosmic energy messages originating from the subconscious mind to levels that
the brain can understand and interpret. These messages, once allocated to lower frequencies
suitable to the brain, are transformed from the real or subconscious concepts they originally represent to their actual or objective counterparts. The subconscious mind also communicates with the brain via the pituitary and solarplex glands. The pituitary gland serves as a bridge
between the pineal and the solarplex glands. The solarplex gland is in reality much more than a gland, it is a central psychic center comprised of many psychic glands. It is the psychic center
responsible for regulating the physical function of various organs within the human body.

I think the essence of reality, whether you call it physical or mental, can be best understood as an undefined paradox. The objective physical world exists as an attempt to solve the paradox. The subjective mind exists as an attempt to solve the paradox. The paradox is never really solved, only replaced with new ones, which is the phenomenon known as "time".

Not only are we blind to many aspects of our personal visual world, we are also surprisingly unaware of this fact. Under normal circumstances, for example, we do not notice that we blink; that we have large retinal blind spots; that our instantaneous spatial, chromatic, and temporal resolution varies dramatically with eccentricity; and that our vision is interrupted several times a second by rapid eye movements (saccades). Indeed, despite all of these considerable distractions, we believe that we see a complete, dynamic picture of a stable, uniformly detailed and colourful world.

It is even tempting to suppose that there is a "me" in there and a place from where "I" observe. This the "Cartesian Theatre" is a powerful illusion propped up by a "nearly impenetrable barrier of intuitions" .One of these intuitions is that a complete visual picture of the observable world is present in the mind at any time - that consciousness "contains" a rich model of the visible world. This is simply not true. Only in the fovea is the information detailed and rich, and every time the eyes move this detailed information is overwritten.

In recent years, a pair of intriguing phenomena has caused researchers working on vision and visual attention to reevaluate many of their assumptions. These phenomena, which have come to be called change blindness (CB) and inattentional blindness (IB), have led many to the conclusion that ordinary perceivers labor under a "grand illusion'' concerning perception - an illusion that is exposed by CB and IB.

That's how it seems to them, but they are wrong.

How could they be wrong? They could be wrong about this because they could be wrong about anythingBbecause they are not gods. How wrong could they be? Until we excuse them for their excesses and re-interpret their extravagant claims in the light of good third-person science, they can be utterly, bizarrely wrong. Once they relinquish their ill-considered grip on the myth of first-person authority and recognize that their limited incorrigibility depends on the liberal application of a principle of charity by third-person observers who know more than they do about what is going on in their own heads, they can become invaluable, irreplaceable informants in the investigation of human consciousness.