Everyday, ordinary human experience puts us into contact with many different things.
Some things are recognized or known quite easily. Other things, however,
are more difficult to perceive or discover.
The existence of God falls into this latter, more difficult,
category. God exists. But we cannot sense him directly. And although the Catholic Church
teaches that human reason CAN prove (or discover) the existence of God,
she does NOT teach that it is EASY for human reason to prove his existence.
In this video, we are going to introduce the “Second Way” that St. Thomas Aquinas invokes
to demonstrate God’s existence by reason alone: The way of efficient causality.
Thinking is not an easy activity. Clear thinking doesn’t just happen. Deep thought
about profound things requires a lot of time and intense effort. This is
why we naturally admire the brilliant philosophers and scientists of history
who have made great discoveries about the profound truths accessible to human reason.
One such brilliant thinker was the thirteenth-century philosopher and
theologian, St. Thomas Aquinas. In his masterpiece, the Summa Theologie,
St. Thomas guides us through five rational proofs for God’s existence.
We recall that each of Aquinas’s “Five Ways” has its own proper argument. Nonetheless, these five
ways fit together and constitute a unified, integral whole. In other words, we can best
appreciate the rational power of Aquinas’s Five Ways if we consider all five in unison—because
each of the five ways approaches the ONE God (the
First Cause of all reality) in light of the MANY aspects of created reality.
Again, in this series of videos, we examine Aquinas’s second rational way
to God. And let us begin our consideration of Aquinas’s Second Way with his own words:
“The second way is from the nature of the efficient cause. In the world
of sense we find there is an order of efficient causes.
There is no case known (neither is it, indeed, possible) in which a thing is found to be the
efficient cause of itself; for so it would be prior to itself, which is impossible.
Now in efficient causes it is not possible to go on to infinity, because in all efficient causes
following in order, the first is the cause of the intermediate cause, and the intermediate is
the cause of the ultimate cause, whether the intermediate cause be several, or only one.
Now to take away the cause is to take away the effect. Therefore, if there be no first
cause among efficient causes, there will be no ultimate, nor any intermediate cause.
But if in efficient causes it is possible to go on to infinity,
there will be no first efficient cause, neither will there be an ultimate effect,
nor any intermediate efficient causes; all of which is plainly false.
Therefore it is necessary to admit a first efficient cause,
to which everyone gives the name of God.”
This is how St. Thomas Aquinas presents the Second Way to God.
If you find Aquinas’s argument here to be complicated and a little bewildering,
don’t feel bad: philosophers and theologians have been studying Aquinas’s Second Way for 750 years,
and everyone feels overwhelmed the first time they study Aquinas’s Five Ways.
In order to understand Aquinas’s argument, let’s
pause briefly to note some of the proof’s big-picture themes and characteristics.
FIRST, we note WHERE the Second Way BEGINS. The argument begins with
dynamics and realities that we recognize in the world around us through HUMAN SENSATION.
Aquinas starts with things that we can SENSE.
This foundation of Aquinas’s Second Way is one of the most important components
of his argument. Why? Because sensible reality is something
accessible to all normal people in all ordinary circumstances.
You don’t have to be a brilliant philosopher or an erudite scientist in order to experience
the world through your five senses (sight, hearing, taste, touch, and
smell). All human persons—from the infant to the elderly—experience the world through their senses.
Therefore, we note that Aquinas’s argument is not built upon an inaccessible, esoteric, or elusive
foundation. He grounds this argument in observable phenomena that all sane people recognize:
we can all sense things that REALLY exist in the REAL world around us. Because sensation is
a part of everyday human experience, it is a very strong foundation for his argument.
SECOND, we note WHAT Aquinas concludes at the END of his argument.
He concludes to the existence of an absolutely unique being
(a being that everyone calls “God”). This conclusion does not surprise us.
However, if we compare WHERE Aquinas begins his argument (human sensation)
with WHAT Aquinas concludes (God exists) we observe something very significant.
The human person cannot directly “sense” God, himself. God is supernatural—beyond our native,
natural capacities of sensation or comprehension. Nonetheless,
Aquinas begins his argument with things that humans CAN sense.
Thus, the Second Way follows a fascinating rational path:
this argument begins with things that we CAN sense (the world around us, causality),
and it ends in something that we CANNOT sense (God).
So this argument reasons FROM what is most immediately knowable
(sensible reality) TO what is not immediately knowable (God, divine reality). Aquinas,
in his arguments, is always careful to proceed from what we DO know to what we do NOT (YET) know.
THIRD, we note how Aquinas CONNECTS the starting point of the Second Way to the conclusion of his
argument: he explains that this is a proof “from the nature of the efficient cause.”
Therefore, in order to understand Aquinas’s argumentation, we will have to investigate
the nature of CAUSALITY in general, and the nature of EFFICIENT causality specifically.
Efficient causality will be the topic of our next (the second) video on Aquinas’s Second Way.
In this introductory video, however, we have seen the broad contours of Aquinas’s second
proof for the existence of God. He BEGINS with what all people can discover and know through
everyday human sensation and experience, and he CONCLUDES that there is a unique being beyond
everyday human sensation and experience called “God.” Aquinas proves the existence
of God through a careful consideration of the nature of efficient causality.
Let us now bring this video to a close. God does exist. He is real. Moreover,
his existence is something that human reason can discover (even without divine faith). Although it
is not easy to prove that God exists by reason alone, it is possible—especially when we are
aided by the wisdom of St. Thomas Aquinas. In the videos that follow, we will continue
to benefit from Aquinas’s wisdom as we examine his second proof of God’s existence, the “Second Way.”
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