If it were true that man is an animal rationale in the sense in which the modern age understood the term, namely, an animal species which differs from other animals in that it is endowed with superior brain power, then the newly invented electronic machines, which, sometimes to the dismay and sometimes to the confusion of their inventors, are so spectacularly more "intelligent" than human beings, would indeed be homunculi. As it is, they are, like all machines, mere substitutes and artificial improvers of human labor power, following the time-honored device of all division of labor to break down every operation into its simplest constituent motions, substituting, for instance, repeated addition for multiplication. The superior power of the machine is manifest in its speed, which is far greater than that of human brain power; because of this superior speed, the machine can dispense with multiplication, which is the pre-electronic technical device to speed up addition. All that the giant computers prove is that the modern age was wrong to believe with Hobbes that rationality, in the sense of "reckoning with consequences," is the highest and most human of man's capacities, and that the life and labor philosophers, Marx or Bergson or Nietzsche, were right to see in this type of intelligence, which they mistook for reason, a mere function of the life process itself, or, as Hume put it, a mere "slave of the passions." Obviously, this brain power and the compelling logical processes it generates are not capable of erecting a world, are as worldless as the compulsory processes of life, labor, and consumption.
Again, we have in the reference to the "worldlessness" of instrumental calculation and its effects a unique Arendtian usage. For Arendt the "world" is profoundly political in its substance, akin to the sense in which when we speak of "worldly" concerns we often mean to indicate more than just planetary or natural concerns, but public and cultural affairs more generally. On p. 52 of The Human Condition, she writes that "the term 'public' signifies the world itself." She continues
This world... is not identical with the earth or with nature... It is related, rather, to the human artifact, the fabrication of human hands, as well as to affairs which go on among those who inhabit the man-made world together [emphasis added --d]. To live together in the world means essentially that a world of things is between those who have it common, as a table is located between those who sit around it; the world, like every in-between, relates and separates men at the same time.
Among other things, it seems worthwhile to draw attention to Arendt's idiosyncratic understanding of the "world" especially since this is the world the love of which Arendt announced in her personal motto, Amor Mundi. Think of the way in which we are born into a speech, a "mother tongue," the existence of which long precedes our birth and will continue on long after our death, but which, for all that still consists entirely of our own performances of it, performances that at once sustain it in its existence but also change it (through coinages, figurative deviations, and so on).