John Calvin Commentary Psalms 49:20

"Man that is in honor, and understandeth not, Is like the beasts that perish." — Psalms 49:20 (ASV)

Man is in honor, and will not understand. Here the prophet, so that he might not be understood as having portrayed the present life (which is in itself a unique blessing from God) as entirely contemptible, corrects himself, so to speak, or qualifies his former statements with a single word. This word implies that those whom he criticizes have lowered themselves to the level of the beasts that perish by mindlessly consuming the blessings God has given, and thus stripping themselves of the honor God had conferred on them.

It is against the abuse of this world that the prophet has been directing his criticisms. These criticisms are aimed at those who indulge excessively in God's blessings without any acknowledgment of God Himself, and who foolishly devote themselves to the transient glory of this world, instead of rising from it to contemplate the things that are above.