We may define a good thing as that which ought to be chosen for its own sake; or as that for the sake of which we choose something else; or as that which is sought after by all things, or by all things that have sensation or reason, or which will be sought after by any things that acquire reason; or as that which must be prescribed for a given individual by reason generally, or is prescribed for him by his individual reason, this being his individual good; or as that whose presence brings anything into a satisfactory and self sufficing condition; or as self sufficiency; or as what produces, maintains, or entails characteristics of this kind, while preventing and destroying their opposites (one thing may entail another in either of two ways simultaneously, or subsequently.