Sensation and Thought


  1. Aristotle’s seeming temporal order in the Metaphysics (Book I, Chapter 2) for the Presocratics by category (in his account Aristotle leaves out some important philosophers while including some obscure ones that I do not include here):
    1. Those that believed in one or more ingenerable and imperishable substances, whose changing modifications cause generable and perishable things

                                               i.     Thales

                                             ii.     Anaximenes (he doesn’t mention Anaximander here)

                                            iii.     Heraclitus

                                            iv.     Empedocles

                                             v.     Anaxagoras

                                            vi.     Atomists

    1. Those that believed that all is one, but appears to sensation to be many

                                               i.     Xenophanes

                                             ii.     Parmenides

                                            iii.     Melissus

    1. The Pythagoreans
    2. (The chronological orders in the three categories are independent, and in fact Aristotle says that the Pythagoreans were “contemporary with these philosophers and before them.” Since Xenophanes was earlier than Heraclitus, it appears that the three lists comprise three contemporaneous sequences.)
  1. Parmenides, Democritus, Socrates, presumably Plato, and Aristotle all made a distinction between sensation and thought as knowing faculties. This handout attempts to trace the development and perpetuation of this distinction.
  2. In Parmenides’ poem, sensation and thought respectively reveal distinct worlds with opposite characteristics:
    1. The world of sensation comprises a pluality of things and is characterized by a variety of cyclical changes that were the main object of explanation (explanandum, thing to be explained) of the Ionian philosophers.
    2. The world of thought is one and unchanging.
    3. Seemingly, the world of sensation is immediate and evident. Our experience begins there.
    4. But the world of sensation is contradictory, and so must yield as regards truth, to the world of thought.
    5. Thought, thus, is introduced into out experience by its critical power, that is, its ability to detect contradiction in the world of sensation.
    6. The character of Being, the world of thought, is a result of applying the requirements, as Parmenides sees them, of  the critical power of thought, and especially the principle of contradiction as he formulates it (what is cannot not be).
  3. Zeno’s paradoxes, as befitting something designed to shore up Parmenides’ way of truth, dwell in the arena of thought. Of the two classes of paradoxes, the paradoxes of plurality are more important for his immediate successors, and of motion for Aristotle.
    1. One of the paradoxes of plurality: if the many are, they must be large and small—so large as to be infinite (as a totality), and so small as to be non-existent.

                                               i.     Things are many, if and only if, the one (all, whole) can be divided into many.

                                             ii.     If things are many, then the all has been divided either finitely or infinitely.

                                            iii.     If finitely, then the many then are also infinite in number, because their boundaries constitute others, and the boundaries between the boundaries and the bounded, ad infinitum. Thus they are both finite and infinite in number.

                                            iv.     If infinitely, then since they have been infinitely divided, they are so small as to have vanished entirely, and in the process, the number and sum of their differences have become infinite. Thus they are as a totality both non-existent and infinite in extent.

    1. (According to J. E. Raven’s treatment of Anaxagoras, aspects of the latter’s cosmology are based on a rejection of a strand of reasoning in Zeno’s paradoxes of plurality, namely the notion that if things were infinitely divisible, they would be both infinitely small (and thus non-existent) and infinitely large as a totality. Anaxagoras accepts the notion that things can be both reduced and expanded without limit.)
  1. (At this stage of this handout I am leaving out Empedocles.)
  2. Anaxagoras. According to J. E. Raven, his philosophy is based on accepting Parmenides’ ban on coming to be and passing away, but rejecting his ban on division. (Things are infinitely divisible, and pace Zeno, this results in no impossibility.)
    1. No characteristic of things has ever come to be or will ever pass away. Rather, originally all things were together, that is, each characteristic was divided so finely as not to be apparent, and all were thoroughly mixed.
    2. Through combination and separation due to the vortex having been started by Mind, the characters of things have become apparent through like being combined with like, and unlike being separated from unlike. Yet all things still have all things within them, but mostly in parts too small to be apparent.
    3. Seemingly the world as it is now is manifest to sensation, whereas the original togetherness and the work of the vortex process are inferences of thought. Why must there have been a togetherness? Perhaps the original togetherness is just an ideal limit—what really needs to be explained is the apparent coming to be and passing away of things with definite characteristics.
  3. In Democritus’ atomism, the cosmology of the atoms and the void is likewise the result of critical reflection on the sense world, although that process of reflection must be reconstructed (since it is not fully in our texts (?)).
    1. That process might be somewhat as follows:

                                               i.     Sense qualities (color, sound, etc.) come to be and pass away. But coming to be and passing away are impossible (because what is cannot not be). Hence, sense qualities are unreal and in particular relative, that is, they arise in the interaction of the sensed and our sense organs. (These interactions can come to be and pass away.)

                                             ii.     Changing interaction implies plurality and change, but not true becoming or passing away (the coming to be and passing away of what is).

                                            iii.     Thus there must be indivisibles (atoms) (because otherwise there would be nothing not susceptible to coming to be and passing away, or perhaps he accepts Zeno’s argument against infinite divisibility), and there must be a void (because otherwise the atoms would not be able to move).

                                            iv.     We do not see the atoms, but only infer them (everything we see is divisible)—hence they are too small to see.

                                             v.     Thus just as in Parmenides, there are two worlds, one revealed though the senses, and one through thought.

  1. Perhaps it would not be an oversimplification to say that sensation reveals the immediate and apparently clear world, while thought reveals its underlying nature. Thought as such seems to be characterized by logic, although there certainly seems to be a logic of sensation of a sort.
  2. Socrates. As in the Republic, there are two worlds, the intelligible and the sensible, one apprehended by thought and the other by sense. The intelligible is the cause of the sensible, and the sensible can be understood only through the intelligible.
  3. Aristotle. The whole point of this handout is to try to clarify Aristotle’s view of the distinction between sensation and thought.
    1. What is clear from the texts:

                                               i.     Animals possess two kinds of knowing faculties, sensation and thought, the latter being possessed only by human animals.

                                             ii.     Sensation is of the individual or particular, thought of the universal.

                                            iii.     Language acquires meaning through a combination of convention (various nations speak various languages) and a kind of modeling of reality in the soul.

                                            iv.     The mind possesses the capacity to form universals from complex sensations in the soul.

                                             v.     Opinion or belief and knowledge are distinct, and one cannot opine and know the same thing.

                                            vi.     To know P is to possess a proof of P.

    1. What is unclear from the texts but important:

                                               i.     Although this is unclear and gives rise to difficulties, the assertions just emunerated seem to imply that “meanings” are of two kinds, complex sensations as recorded in memory, and universals. So the name “Socrates” acquires meaning through sensation, while the name (noun) “human being” acquires meaning through a two-step process involving sensation and thought. Thus it seems that a proposition as it exists in the mind can be composed either of complex sensations or of thoughts (universals)—examples: “Socrates is here” vs. “All humans are mortal.”

                                             ii.     This seems unsatisfactory as regards logical relations between universal and singular propositions.