1.2.3 Perceptions and Appearances

Version 1.0 September 2016                                        (Previous Version)

Some people restrict a discussion of perception to the five senses: smell, taste, touch, hearing, sight.  But our conscious minds also receive stimuli directly from our bodies and brains.

In the first instance, we distinguish between mental events, our bodies, and the rest.  Each of these is the source of different kinds of “perceptions�, which we treat as direct awareness in our minds.

●   Thoughts appear in our consciousness as if from nowhere; 

●   Visceral emotions, bodily reactions such as an adrenalin rush or oxytocin releases generate feelings, such as love, hate and disgust;

●   We are often aware of the position of our body, arms, legs and head, and muscle tension;

●   We are often aware of the state of some internal organs, such as the heart, lungs, stomach, bladder and bowels;

●   External events impinge on the sense organs of the so-called five senses: smell, taste, touch, hearing, sight.

Our elementary perceptions and subjective conscious experience are qualia, patches of colour, tastes, pains, and so on.  Our brains partition our experience, dividing it up into useful chunks, assembling these qualia into things and events (changes in the qualia or changes in the things).

The mechanisms by which we receive these stimuli, our eyes and ears, nose and tongue, nervous systems and so on, have evolved and are strictly limited.

●   Human eyes can only detect a small fraction of the electromagnetic spectrum that we call visible light.  Our mammalian eyes evolved to make the most of the sunlight: we detect the wavelengths of sunlight that are strongest.  We can also see partly in dim moonlight.  Humans, like primates have colour vision, evolved to allow our fruit eating ancestors to detect when fruit is ripe.  We can’t see infrared or ultraviolet, even though these would be very useful in the dark and other circumstances.

●   Human ears can detect sounds in the range of about 20 to 40,000 hertz (cycles per second), from very soft (say 10 decibels) to painfully loud (over 125 decibels).  Our ears detect the wavelengths of human speech well.  Whales can detect lower frequencies, dogs higher, bats higher still.

●   Smell is really a method of detecting various chemicals in the surrounding air or water.  It is a very primitive method of perception that we share with the simplest animals.  Our nose has direct access to our brains.  Even human noses can detect very small concentrations of substances, and distinguish a huge variety of smells.  Chemicals that are signs of decaying flesh or common natural poisons smell disgusting or revolting, make us vomit or get away from the source.

●   Taste is similar to smell, in that it detects various types of chemicals.   We humans have taste buds for salty, sweet, sour and bitter substances distributed fairly evenly over our tongues.  Our brains combine the signals from these into many complex taste sensations, both pleasurable and not.

●   Touch is actually a combination of systems.  We humans have receptors in our skin for touch itself, pressure, vibration, temperature and pain.  These can be pleasurable or extremely painful.

Modern science tells us that all of the so-called five senses are based on electromagnetic forces, which control light (photons) and chemical reactions.

From our bodies we receive inputs of three major kinds:

●   Primordial feelings that enter our minds as a result of bodily responses to external stimuli or internal functioning (in practice often via chemicals such as hormones) which can include excitement, heightened attention, lethargy, attraction, repulsion, disgust and so on.

●   Proprioception signals the tension in joints and striated muscles (e.g. in our limbs and trunk) and some internal organs;

●   Interoception signals the condition of body tissues, such as the degree of contraction or distension of smooth muscles (e.g. in the gut, lungs and blood vessels).

Thoughts come into our heads seemingly of their own accord. 

●   Some people mislead themselves into believing that they can make specific thoughts come to mind.  Indeed, there are tricks we can play on our minds to help us remember things, but these often involve generating other stimuli or following some learning strategies so that the required thought comes to mind more quickly, but ultimately “by itselfâ€�. 

●   The Buddhist practice of mindfulness may begin with relaxed meditation focussing on breathing in and out, as a technique to quieten the mind so that the real work can begin.  The essence of mindfulness is on watching thoughts pass through your mind.

Philosophical discussions of perception often treat it as a passive process, of signals coming into the mind.  This may be reasonably accurate when we are sitting still meditating or even sitting writing.  But our perceptual understanding comes with interacting with objects, and as we interact we frequently change our perceptions.  A ball that looks smooth from a distance may be show a rough surfaced when we look at it closely, or better yet, take it in our hands and feel it.  A table may look white in sunlight but pinkish if we darken the room and turn on a red light.  How we construct our mental model of the object is discussed in a later section.  Here we are focussing on the sensations.

We suggest the following summary:

 

1.2.3.1 Altered Perceptions

We can alter our experience of reality in a variety of ways: taking recreational drugs, such as alcohol, cannabis, ecstasy, LSD, speed, cocaine, heroin and so on.  We can also do it by various physical exercises, such as prolonged chanting, dancing, and various mental exercises, such as mediation.  These can alter our perceptions, but more importantly alter our feelings. 

Some people think that this expands our minds, and indeed it does give us food for thought, and reinforces the notion that our normal experience is limited.  (See for instance Aldous Huxley’s The Doors of Perception and Heaven and Hell.)

Some go further to suggest that the different experience of reality is evidence of some higher or better reality, or even of the supernatural, but this is going too far.

So what can we conclude about the underlying reality whose appearances we perceive?