Week 6 Notes: Sensation and the External Senses

Week 6 Notes: Sensation and the External Senses

• Overview and aim

  • Week 6 focuses on sensation, especially external sensation through the five senses, and its significance for understanding the distinctly human way of rationality.
  • Next week examines internal senses and their role for intellect.
  • Sensation anchors the animal form of life; helps compare subhuman animals to humans, highlighting both similarities and crucial differences.
  • Key distinction: nonhuman animals are not fully human nor purely physicalistic; they have cognition, perception, desire, emotion, attachments, and even rudimentary deliberation, yet lack true rationality, free will, and genuine speech.

• Animals vs. humans: what differs

  • Animals can perceive, desire, deliberate in basic ways, and form emotional bonds (e.g., mother-infant bonds; anger, fear).
  • They can discover and use instruments, seek their own good, and may sacrifice for offspring, indicating species-level priorities.
  • Humans value both individual and species, and possess what we call genuine rationality (the discernment of the what-ness/essences of things) and speech (including art as representation of essences).
  • Animals lack true speech and the capacity to articulate or grasp abstract essences; intellect involves grasping natures that go beyond immediate sensation.

• Cognition, perception, and their general nature

  • Cognition (perception, knowledge) is not the substance of a thing; it is an accidental, noble activity realized by an animal or person.
  • Imminent vs. transitive actions:
  • Imminent actions have their end present in the act itself (end contained within the action). Examples include:
    • Seeing: while I am seeing, the act already accomplishes its end.
    • Knowing (cognition), and loving: as soon as the will is directed toward something, the activity is at once present.
    • In contrast, transitive actions begin and end (e.g., building something).
  • Hierarchy: immaterial activities are more prominent in higher beings; God is pure imminent activity (knowing).
  • Cognition/perception is a paradox: the object is present in the subject but remains distinct from its substantial being (intentionality). This gives rise to the idea of an intentional mode of being: the object is in some sense present within the knower, yet remains outside in its own right.
  • All cognition is, in some sense, immaterial: it involves bringing a material thing into a different mode of being (content), but the thing itself does not become one with the knower.
  • The outset of knowledge: sensation is the beginning of all knowledge; even abstract truths (e.g., quadratic equations) rely on prior sensory experiences (counting and numbering of things) that ground abstract reasoning.
  • Example: counting and number originate in sensory encounters with the world (parents counting objects, etc.).

• The nature of sensation: material and immaterial coexistence

  • Sensation involves physical processes (e.g., light waves reaching the eye, sound waves, nerve activity) plus an immaterial impression: what is present to the mind through sensory form (color, shape, odor, texture, etc.).
  • Contents of sensation are material qualities (colors, textures, odors, sizes, shapes), but the act of sensing brings about an immaterial impression (the object as present to the mind).
  • Sensation thus has both corporeal and incorporeal aspects: physical organs mediate but the positivity of sensing is the immaterial impression of the object.
  • This sense of “presenting” something out there but without its matter suggests an almost “super-material” character of cognition.
  • Aristotle emphasizes that sensation is bound to bodily form: the organs are crucial (eyes, ears, nose, skin, tongue), and physical processes are necessary.
  • A strong sense of the unity between sense power (the ability to sense) and sense organ (the anatomical instrument): the power is not identical with the organ but is realized through it; the organism as a whole undergoes sensing.
  • Over-stimulation can damage the sense power: excessive light can injure the eye; loud sounds can damage hearing; this shows the intimate coupling of power and organ.
  • In sensation, unlike higher reasoning, extreme intelligibility does not strengthen the mind; it can harm the organ. The next weeks contrast this with how rational thinking behaves.

• The five external senses, and their objects

  • Aristotle’s objects of sensation are divided into three kinds: proper sensibles, common sensibles, and indirect/accidental sensibles.

  • 1) Proper sensibles (the objects specific to each sense)

  • Sight: color

  • Hearing: sound

  • Smell: odor (scent)

  • Taste: flavor, subdivided into four categories: ext{bitter}, ext{sweet}, ext{sour}, ext{salty}

  • Touch: texture, with several subcategories (hot vs cold; wet vs dry; hard vs soft; smooth vs rough)

  • Note: touch is foundational and captures many aspects of bodily nature; it also extends to broader qualities (humidity, radiation, electromagnetism, gravity) though some aspects may be subtler for humans.

  • 2) Common sensibles (objects detectable by more than one sense)

  • Motion, rest, size, shape, and number

  • They are related to quantitative aspects: motion/rest involve detecting change in quantity between positions; size and shape are about quantitative and geometric properties; number concerns counting and quantity.

  • Coordination across senses: sight can perceive shape; touch can perceive shape too, even if the primary object for touch is texture.

  • 3) Indirect/accidental sensibles (substances of things themselves)

  • Sensation directly perceives only accidental properties (proper/common sensibles). It indirectly apprehends the substance (the whatness) of things.

  • For nonhuman animals: sensation is most concerned with the substance insofar as it relates to their life (e.g., a lion senses scent and movement to find prey) but does not grasp the deer as a deer as such; it responds to the substance’s sensible cues (smell, look, taste).

• The nature of sensation and the role of medium

  • All five external senses require a medium to function; they act at a distance (sight, hearing, smell) or at contact in the case of touch and taste.
  • Sight, smell, and hearing rely on a medium (light waves, air-borne sound waves, or scent molecules) mediating between the object and the sense organ.
  • Touch and taste do not act at a distance in the same way, but they still operate through a medium (e.g., moisture in the mouth for taste; skin as the medium for touch).
  • Aristotle identifies that sight is closest to incorporeality (and hence closest to intellect), while touch is the most corporeal and furthest from intellect; yet touch remains the most real in verifying reality.
  • Sight is considered the most noble sense in some respects (closest to intellect); touch, while more corporeal, is foundational to the other senses and particularly refined in humans.
  • Pigeons, among others, can sense electromagnetism, illustrating cross-species differences in perceptual modalities.

• Proper, common, and indirect sensibles in more detail

  • Proper sensibles are qualities that each sense uniquely discerns: color (sight), sound (hearing), odor (smell), flavor (taste), and texture (touch with its own sub-senses).
  • Common sensibles are quantities that can be apprehended by multiple senses: motion, rest, size, shape, number. These reflect the sense of quantity and spatial relations.
  • Indirect/accidental sensibles relate to the substances of things themselves and are not directly picked up by sensation; intellect is required to directly grasp the substance or whatness.
  • The life of animals emphasizes that while sensation may not furnish direct knowledge of substances, it still targets the important objects (e.g., a lion’s appetite targets the deer’s substance, even if the lion does not conceptualize deer as such).

• The reception of sensation: physical impressions and immaterial impressions

  • Each sensation involves two intertwined processes:
  • A natural (physical) impression: the physical interaction with the object (light waves hitting the eye; sound waves hitting the eardrum; heat warming the skin; etc.).
  • An immaterial impression: the immediate present-to-mind experience of the object (the actual perception of color, warmth, sound, etc.). This immaterial aspect is what we call the sensation itself.
  • Thus, sensation is reception of physical content in a non-physical manner; it represents a form of action at a distance that pure physicality cannot achieve.
  • Aquinas distinguishes between natural/physical impressions and immaterial impressions to explain how perception occurs without the physical matter of the object becoming part of the perceiver.

• The sense power, sense organ, and the body-soul relation

  • The sense power (e.g., sight) is the faculty that enables sensation; the sense organ (e.g., the eye) is the physical instrument that actualizes the power.
  • The sense power is rooted in the soul, and the sense organ is physical; they are inseparable in the act of sensing: the power manifests through the organ.
  • The organism as a whole experiences sensation; the organ undergoes physical impressions, while the power experiences immaterial impressions.
  • Overstimulation can damage the sense power by harming the organ (e.g., too much light can cause blindness; too loud sounds can cause hearing loss), illustrating the intimate link between power, organ, and sensation.
  • Unlike reason, which can grow stronger through engagement with intelligible content, extreme sensory input can harm the faculty of sensation.

• Practical and epistemological implications

  • Sensation is the starting point for all knowledge; even abstract mathematics ultimately relies on sensory-origin data (counting, numbers, and the world’s particulars) that ground higher cognition.
  • The dependence on sensation underscores the continuity between perception and knowledge: without sensible content, rational forms cannot operate.
  • The distinction between sensation and intellect highlights a dual aspect of human cognition: concrete, material-entrained perception and abstract, rational reflection that grasps essences.
  • The intentionality of perception (object-present-in-subject but as other) grounds a robust philosophy of mind: objects acquire a presentness within the knower while retaining their own substance.

• Summary of next steps

  • Next week will shift from external senses to internal senses and examine how intellect emerges from the interior rational faculties.

• Important references and terms to remember

  • Imminent vs. transitive actions: end is contained in the act; e.g., seeing, knowing, loving vs. building, walking to a destination.
  • Proper sensibles: the senses’ unique objects (color, sound, odor, flavor, texture; sub-senses for hot/cold, wet/dry, hard/soft, smooth/rough).
  • Common sensibles: motion, rest, size, shape, number.
  • Indirect/accidental sensibles: substances of things themselves; sensation primarily apprehends accidents.
  • Natural (physical) impression vs immaterial impression: two aspects of sensation that together explain how objects are present to the perceiver without their matter becoming part of the perceiver.
  • The sense power vs the sense organ: power is the faculty; the organ is the instrument; unity in sensation requires both.

• Key quotes/concepts to memorize

  • “A sense or sense power is that which can receive physical substances, individual material substances, without their matter.” (Aristotle, De Anima II.12)
  • “Sensation is the ability to receive physical or material substances without their matter, through sensory accidents.”
  • “Sensation is a passive or receptive power, but its act constitutes a self-movement of a very high order in an animal.”
  • “The end is contained within the action” (imminent activities).
  • “Vision is closest to incorporeality; touch is the furthest, but touch remains the most real in verifying reality.”

• Mathematical/quantitative notes (for quick reference)

  • The external senses are described in terms of quantitative relations (common sensibles). Useful reminder: the five senses collectively amount to 5 external senses.
  • Common sensibles involve quantities and measurements (motion, rest, size, shape, number), underscoring the role of quantitative reasoning in perception.

• Connections to broader themes

  • The analysis links sensation to epistemology (how we know) and philosophical anthropology (human nature vs animal nature).
  • It lays groundwork for later exploration of how internal senses support intellect and the full scope of rational life.
  • It raises ethical and metaphysical questions about the relationship between body and mind, and whether perception itself involves an element of the non-material.

• Examples and illustrations from the lecture

  • Animal life: mother bear with cubs illustrates attachment and emotion; animal actions show deliberation about the good of the species rather than the individual.
  • The lion example shows indirect apprehension of substances: the lion wants the substance (deer) but perceives only the signs (scent, appearance) rather than the deer as a deer.
  • The freeway truck example demonstrates misperception at the level of common sensibles (motion and velocity) and the fallibility of perceptual judgments under certain conditions.
  • Overexposure examples: looking at the sun or listening to loud noise illustrates how sense power can be damaged by excessive physical impressions.

• Quick gloss on the philosophical payoff

  • The Aristotelian framework for sensation blends physics (mediums, waves, and bodily organs) with a robust epistemology (immanent acts, intentional objects, and the beginning of knowledge).
  • The Aquinian refinement helps explain how perception can convey something about the world without making the perceiver literally identical to the perceived object.
  • The discussion sets the stage for the later contrast between sensation and intellect, clarifying why rational thought can rise above raw sensory data yet remains grounded in it.