Manava Dharmashastra 1.85

1.85

uktasya kālabhedena padārthasvabhāvabhedasyopasaṃhāraḥ | dharmaśabdo na yāgādivacana eva, kiṃ tarhi padārthaguṇamātre vartate | anye padārthānāṃ dharmāḥ pratiyugaṃ bhavanti, yathā prāk darśitam | yathā vasante'nyaḥ padārthānāṃ svabhāvo'nyo grīṣme'nya eva varṣāsvevaṃ yugeṣvapi | anyatvaṃ cātra na kāraṇānāṃ dṛṣṭakāryatyāgena kāryāntarajanakatvam, api tvaparipūrṇasya kāryasyotpatteḥ śakterapacayāt | tadāha yugahrāsānurūpata iti | hrāso nyūnatā |

During the Kṛta-cycle, the characteristics of men are of one kind,—of different kinds during the Tretā and the dvāpara,—and of yet another kind during the Kali-cycle;—this being due to the deterioration of each suceeding Cycle.—(85)

Medhātithi’s commentary (manubhāṣya):
This verse sums up what has been said in regard to the diversity in the nature of things based upon the difference in time.

The word ‘Dharma’ here is not restricted to the sense of sacrifice and such other acts (prescribed by the Veda); it stands for the characteristic of things in general. The meaning thus is that in each Cycle, the character of things varies, as shown before (in verses 83 and 84); just as, for instance, the character of things during the Spring is of one kind, of a different kind during the Summer, and of yet another kind during the Rains,—so it is in connection with the Cycles also.

By ‘difference’ it is not meant that things cease to bring about effects that they are found (at one time) to produce, and bring about other effects; what is meant is that they become incapable of bringing about their complete effects; and this by reason of the decrease in their potency. This is what is meant by the phrase—‘this being due to the deterioration of each succeeding Cycle,’—‘deterioration’ meaning inferiority.—(85).