Ancient Atomism & Sophism


Teachings & Discoveries

Quotes & Notes

441 B.C.


  • Melissuss’ Challenge (1) thought to have inspired Leucippus
  • Argued that the nonexistence of nothing (2) implies that the One is infinite not finite (as Parmenides said).
  1. “If there were a many, these would have to be of the same kind as I say the one is.”
  2. “[W]hat is empty is nothing.  What is nothing cannot be.”

435 B.C.


415 B.C.


  • The void -- empty space -- exists. (1)
  • There are really only atoms (infinitely many) and the (infinite) void. (2)
  • Atoms are minute (invisible) solid units that are
    • indestructible, impenetrable, and indestructible
    • differently shaped & sized
    • unalterable but moveable
  • Atomic Motion & Combination cause all things
    • Atoms move randomly like motes in a shaft of sunlight
    • Colliding atoms stick together to form larger objects. 
  • "Leucippus and Democritus virtually make all things number too, and produce them from numbers." (Aristotle)
  • Sensible (and high-level) qualities of things have only nominal or subjective existence. They arise from the effects of different atomic structures on our minds. E.g., (7)
    • things whose space is only loosely filled with atoms -- e.g. sponges -- feel soft to us.
    • things with sharp pointed atoms that scrape the tongue taste bitter to us.
    • things with differently shaped surface atoms reflect light differently look differently colored to us
  • The souls of humans and animals are themselves formed of the finest, most perfectly spherical, and hence most volatile atoms.
  • Determinism: All things happen of necessity. (3)
  • Saw no conflict between Atomic Theory & ethics, himself. Enjoins pursuit of happiness via moderation & enjoyment of higher (mental) pleasures. (8)(9)
  • Epistemology: (5)(6)
    • sensory experience gives only nominal understanding of how things appear to us. 
    • intellectual analysis yields true apprehension of things as they really are.

1.        “What is not does exist, no less than what is.”

2.        “[All that exists are] atoms and empty space; everything else is merely thought to exist.”

3.        “All things happen by virtue of necessity, the vortex being the cause of the creation of all things.”

4.        “By the senses we in truth know nothing sure, but only something that changes according to the disposition of the body and of the things that enter into it or resist it.” (Frag. 9)

5.        “There are two forms of knowledge, the trueborn and the bastard. To the bastard belong all these: sight, hearing, smell, taste touch. The trueborn is quite apart from these.” (Frag.11)

6.        “[W]hen investigation must be carried farther into that which is still finer (than the minimum sensible) then arises the genuine way of knowing which has a finer organ of thought.”

7.        “In name there is sweet, in name there is bitter; in name there is warm and in name there is cold; in name there color. But really, there are atoms and the void.” (Frag.9)

8.        "The good and the true are the same for all people, but the pleasant is different for different people." (Frag.69)

9.        “[Happiness dwells not in herds and gold; the soul is the dwelling-place of the ‘daimon’.” (Frag.171 [Almost “fortune”])



1.        “Hence, according to the Atomists' theory, if my mind proceeds from propositions (1) and (2) [‘All men are mortal’ and ‘All Greeks are men’] to proposition (3) [‘All Greeks are mortal’], it is not because I recognize that the premises imply this conclusion; it is just because . . . my mind atoms had the velocity and direction they happen to have.”  (97)

2.        “[On the Atomists' theory] the activity of "deciding to get up" is simply another motion of your mind atoms . . . determined by the antecedent motions of . . . atoms. Hence, however much you think that you "chose" and that you could have chosen otherwise, your getting up is a necessary result of antecedent events. . . . Hence, your feeling that you could have stayed in bed is an illusion.” (98)


300 BC
“Death is nothing to us, for that which is dissolved is devoid of sensation.”


  • infinitely many atoms eternally falling through the infinite void.
  • atoms have weight in addition to size & shape & motion
  • swerve hypothesis: sometimes, inexplicably, they swerve (2)
  • explains how collisions got started
  • leaves scope for free will (4)
  • Belief in Atomism -- since it's unconducive to belief in immortality -- conduces to happiness. (If there's nothing for us after death there's nothing to fear from it.) (0)
  • Knowledge must keep close to sensation. Since mathematics doesn't apply to reality, it's useless. (1)(3)(4)

1.        If you fight against all your sensations you will have no standard by which to refer and thus no means of judging even those sensations which you pronounce false."

2.        "It must needs be that the first-bodies swerve a little; yet no more than the very least.”

3.        ”Now the universal whole is a body, for our senses bear us witness in every case that bodies have real existence; and the evidence of our senses ought to be the rule of our reasonings about everything which is not directly perceived.  Otherwise, if that which we call the vacuum, or space, or intangible nature, had not a real existence, there would be nothing in which the bodies could be contained, or across which they could move, as we see they really do move.”

4.        “And who [is wisest and happiest] has no belief in necessity, which is set up by some as the mistress of all things, but he refers some things to fortune, some to ourselves, because necessity is an irresponsible power, and because he sees that fortune is unstable, while our own will is free; and this freedom constitutes, in our case, a responsibility which makes us encounter blame and praise. “


455 BC


“[I teach how] to make the weaker cause the stronger.”


“[Sophists are] shopkeepers with spiritual wares.” (Plato 313c5-6)


  • There is no objective Truth or Reality: Truth is subjective and relative (1)
    • what I believe is my truth 
    • what you believe is your truth.
    • Nevertheless, some beliefs are more useful than others. (3)
  • There is no objective value: Value is subjective and relative: (2)
    • some things are good for me
    • others might be good for you
    •  nothing is good or bad absolutely: nevertheless some values might still be more useful than others. (3)
  • Agnosticism: cannot be sure of the existence or nature of Gods. (4)
    • nevertheless to go along with the religious practices and moral preachments of your society is the most expedient course.
  1. “Man is the measure of all things, of things that are that they are, and of things that are not, that they are not.”
  2. “[W]hatever practices seem right and laudable to any particular State are so for that state, so long as it holds by them.”
  3. "In this way [in that some views are more expedient] it is true that some men are wiser than others and that no one thinks falsely."
  4. “With regard to the Gods, I cannot feel sure either that they are or that they are not, nor what they are like in figure; for there are many things that hinder sure knowledge, the obscurity of the subject and the shortness of human life.”

CONTROVERSIAL POINT: Does "man is the measure" mean truth is relative to the (1) individual, (2) society, or (3) humankind. 


443 BC


“… for it is the same thing that can be thought and that can be.” (4) (Parmenides)

  • Nihilism: Nothing exists (2)
  • Skepticism (2)
    • If there were anything, it could not be known
    • If there were knowledge of anything, it could not be communicated. (4)
  • Renounced philosophy: declined to answer questions of truth and morality. (1)
  • Advocated rhetoric in place of philosophy.
    • rhetoric = the art of persuasion
    • practical psychological knowledge of human suggestibility & how to exploit it should be cultivated & applied for ones persuasive purposes. (3)
  1. [Tragedy is] a deception which is better to cause than not … to succumb to it shows greater powers of artistic appreciation than not to.
  2. First and foremost, that nothing exists; second, that even if it exists it is inapprehensible to man; third, that even if it is apprehensible, still it is without a doubt incapable of being expressed or explained to the next man.
  3. The effect of speech upon the condition of the soul is comparable to the power of drugs over the nature of bodies.
  4. Anything, then, which a man has not in his own consciousness, how can he acquire it from the word from another, or by any sign which is different from the thing except by seeing it if it is a colour, or hearing it if it is a sound.


440 BC

  • Might makes right. (1)
  • Advocate of “natural law”. (2)
  • Stressed arguments of probability and the importance of different kinds of evidence.


  1. “[Justice] means nothing but what is to the interest of the stronger party.”
  2. “The gods do not see human affairs: otherwise they would not have overlooked the greatest of all blessings among mankind, Justice -- for we see mankind not using this virtue."