Here you will find the Long Poem Book I - Part 06 - Confutation Of Other Philosophers of poet Lucretius
And on such grounds it is that those who held The stuff of things is fire, and out of fire Alone the cosmic sum is formed, are seen Mightily from true reason to have lapsed. Of whom, chief leader to do battle, comes That Heraclitus, famous for dark speech Among the silly, not the serious Greeks Who search for truth. For dolts are ever prone That to bewonder and adore which hides Beneath distorted words, holding that true Which sweetly tickles in their stupid ears, Or which is rouged in finely finished phrase. For how, I ask, can things so varied be, If formed of fire, single and pure? No whit 'Twould help for fire to be condensed or thinned, If all the parts of fire did still preserve But fire's own nature, seen before in gross. The heat were keener with the parts compressed, Milder, again when severed or dispersed- And more than this thou canst conceive of naught That from such causes could become; much less Might earth's variety of things be born From any fires soever, dense or rare. This too: if they suppose a void in things, Then fires can be condensed and still left rare; But since they see such opposites of thought Rising against them, and are loath to leave An unmixed void in things, they fear the steep And lose the road of truth. Nor do they see, That, if from things we take away the void, All things are then condensed, and out of all One body made, which has no power to dart Swiftly from out itself not anything- As throws the fire its light and warmth around, Giving thee proof its parts are not compact. But if perhaps they think, in other wise, Fires through their combinations can be quenched And change their substance, very well: behold, If fire shall spare to do so in no part, Then heat will perish utterly and all, And out of nothing would the world be formed. For change in anything from out its bounds Means instant death of that which was before; And thus a somewhat must persist unharmed Amid the world, lest all return to naught, And, born from naught, abundance thrive anew. Now since indeed there are those surest bodies Which keep their nature evermore the same, Upon whose going out and coming in And changed order things their nature change, And all corporeal substances transformed, 'Tis thine to know those primal bodies, then, Are not of fire. For 'twere of no avail Should some depart and go away, and some Be added new, and some be changed in order, If still all kept their nature of old heat: For whatsoever they created then Would still in any case be only fire. The truth, I fancy, this: bodies there are Whose clashings, motions, order, posture, shapes Produce the fire and which, by order changed, Do change the nature of the thing produced, And are thereafter nothing like to fire Nor whatso else has power to send its bodies With impact touching on the senses' touch. Again, to say that all things are but fire And no true thing in number of all things Exists but fire, as this same fellow says, Seems crazed folly. For the man himself Against the senses by the senses fights, And hews at that through which is all belief, Through which indeed unto himself is known The thing he calls the fire. For, though he thinks The senses truly can perceive the fire, He thinks they cannot as regards all else, Which still are palpably as clear to sense- To me a thought inept and crazy too. For whither shall we make appeal? for what More certain than our senses can there be Whereby to mark asunder error and truth? Besides, why rather do away with all, And wish to allow heat only, then deny The fire and still allow all else to be?- Alike the madness either way it seems. Thus whosoe'er have held the stuff of things To be but fire, and out of fire the sum, And whosoever have constituted air As first beginning of begotten things, And all whoever have held that of itself Water alone contrives things, or that earth Createth all and changes things anew To divers natures, mightily they seem A long way to have wandered from the truth. Add, too, whoever make the primal stuff Twofold, by joining air to fire, and earth To water; add who deem that things can grow Out of the four- fire, earth, and breath, and rain; As first Empedocles of Acragas, Whom that three-cornered isle of all the lands Bore on her coasts, around which flows and flows In mighty bend and bay the Ionic seas, Splashing the brine from off their gray-green waves. Here, billowing onward through the narrow straits, Swift ocean cuts her boundaries from the shores Of the Italic mainland. Here the waste Charybdis; and here Aetna rumbles threats