Daily Inspiration Quote by Thomas Aquinas

Aquinas frames an argument from the observed contingency of the world to the existence of a being that cannot fail to be. Many things come into existence and pass away, so their being is not guaranteed; they are contingent. If everything were contingent, there would be a time when nothing existed, and from nothing, nothing follows. To explain why anything exists now, Aquinas infers that at least one being is necessary. But he does not stop there. Some necessary beings, he says, might still owe their necessity to another. If that causal dependence ran back without limit, the explanation would never arrive at anything that truly accounts for the whole chain. So he posits a terminus: a being necessary of itself, whose essence does not allow nonexistence, and which bestows necessity on others.

The phrase necessary of itself points to a source of reality that is not composed, not dependent, and not contingent on conditions. Later Thomistic language casts this as ipsum esse subsistens, subsistent being itself, pure act with no unrealized potential. The claim that it is the cause of necessity in other things extends beyond a first spark at the start of time. It describes an ongoing dependence: contingent beings are held in being by the necessary being here and now. When he adds that all people call this God, Aquinas makes a conceptual identification, not a leap to the full content of Christian doctrine. He is arguing for a metaphysically ultimate, self-sufficient ground of being.

Critics challenge whether an infinite regress is impossible, whether modal reasoning supports a unique necessary being, and whether the cosmos itself could be necessary. Supporters invoke the principle of sufficient reason: if contingents exist, there must be a noncontingent explanation. The lasting force of the argument lies in its demand that dependence and change point to an unconditioned source that does not itself stand in need of a cause.