whence it follows that true judgment and science are not the same[1].
Theætetus, pressed by this objection, attempts a third definition of science, and says it is true judgment in conjunction with reason. But then, observes Socrates, how are we to distinguish the things that can be known from those that cannot? For instance, elements cannot be defined, but things composed of them can be defined. Again, elements can be perceived but not known, for he who cannot give an explanation of a thing cannot know it, but things compounded of them, because they can be defined, can also be known. Theætetus agrees to this; but Socrates is not satisfied with the statement, that the elements are unknown, but the nature of things compounded of them known. He illustrates his objection by an examination of the component parts of a syllable, and shews that if a whole is known its parts must also be known ; if, then, letters are the elements of a syllable, being also the parts of it, they must also be known as well as the syllable[2].
But in order to ascertain the accuracy of Theætetus's last definition of science, it is necessary to determine the meaning of the word logos. First of all, then, it may mean the expressing one's thoughts by means of words, but in that case there will be no difference between true judgment and science. Secondly, it may mean the being able to describe a thing by its elements; but this has been already answered in considering the elements of syllables. Lastly, it may mean definition; but it is absurd to say that science is true judgment joined to definition, for definition can only be of that which a person already knows, so that this would be to say that science is true judgment joined to science[3].
At this point the argument is broken off, without having been brought to any satisfactory conclusion. But Socrates requests that they may meet again the following day and continue the discussion.
