Questions and Answers
What is human intelligence? How is it different from artificial intelligence?
In his Summa Theologica, St. Thomas Aquinas explains that human intelligence is a faculty for knowing in the soul of man.1 This faculty or power has a certain proper operation and a certain object.
The object of the human intellect refers to what it is designed to receive. And it is important to understand that the mind is a receptive faculty. It is not made to produce knowledge on its own. Rather, it is meant to produce knowledge through the reception of its object, which is outside of it. Human knowledge is objective, not subjective. We do not make truth; we understand what is true.
What is that object of the human mind? It is, says St. Thomas, “ens in universali” or “universal being.”2 The object of the human intellect is reality, all that exists out of itself. It is made to understand reality by receiving reality into itself and performing an act of understanding on that reality, which effectively consists in producing a concept that mirrors reality.
How does this work? Well, God has provided humans with certain windows to the outside world which we call the “external senses”: sight, hearing, touch, taste, and smell. What these senses experience of reality is passed on to the mind via an internal image or phantasm. But because sensations are material and the human intellect is a spiritual faculty, it has to perform an operation on those sensations to make them intelligible. We call this operation “abstraction.” It is performed by a particular function of the mind called the agent or active intellect.
It is through this double operation of the human mind—the reception of reality and the act of understanding that reality—that humans are able to have an abstract knowledge of the world around them. This knowledge is of a different order than the knowledge which our senses provide us. The senses provide what is individual and particular of reality, while the intellect grasps what is universal. Say, for instance, you are looking at a turtle. The senses grasp only what is of this moment and what pertains to this particular turtle; the intellect, on the other hand, is able to grasp what pertains to all turtles, for all time.
Here is how I explain this difference in another place:
“The mind has the ability to read into the data of sense and form a concept from that particular data that corresponds to all instances of the phenomenon to which it testifies. Philosophers refer to our concepts as ‘universals,’ because they unite many individual instances into a generic notion that contains only what is common to those individuals and nothing of what is particular to any one of them. Just take the definition of almost any noun in your dictionary, such as ‘abbot’ or ‘abacus’ or ‘abalone’. The definitions indicate only what is true of all instances of the noun.
Both intellect and sense are able to receive reality and correctly reflect it with their respective powers, but the way in which they do so is different. The intellect reflects the common or universal aspects of reality with its concepts, while sensation reflects the particular aspects of reality with its internal sense images. In this reflective capacity, both sense and intellect act like mirrors of the outside world.”3
This ability to grasp universal being, however, is not the most important power of the human intellect; it is much more than a concept-forming faculty. It also has the ability to compare its concepts with one another to make judgments about reality. It can also combine judgments to form new judgments in the process we call reasoning. Fr. Wallace explains these operations as follows:
“The second act of the mind, judging, is the act of combining concepts to form meaningful statements, as seen in the expression ‘Grass is green.’ Here the intellect juxtaposes ‘grass’ and ‘green’, decides that the two go together, and so proceeds to affirm ‘green’ of ‘grass.’ The third act of the mind, reasoning, goes beyond this, for it uses the products of judgment to yield further meaningful statements. It is the act of discoursing from two or more statements to conclusions that are entailed by them. An example would be the complex expression ‘Chlorophyll is green; grass contains chlorophyll; therefore, grass is green.’”4
It is really through these judgments that the human mind attains truth, in its truest sense (if I can speak in that way), because it is by the judgment that it makes a conscious affirmation about reality. The mind is not only reflecting reality with its concepts; it is accurately asserting what reality is.
When we consider this amazing power that God has conferred upon human beings, the ability to grasp the being of the things of reality and be aware of one’s understanding, it is important for us to realize what separates us both from God and machines. God has given us the power of thinking, and He has done so by creating for us a rational soul. We are not able to do this for our machines because we cannot create souls.
Every difference between artificial intelligence and human intelligence flows from the fact that we have rational souls and our machines do not. Every similarity between artificial intelligence and human intelligence flows from man’s best attempts to make machines mimic what human souls are able to do. Let us try to understand some of these similarities and differences.
Souls are an immaterial center of command and organization. Our human soul unifies all the parts of our body and makes it to act as a whole, for our overall good. This is why, when human souls are separated from their bodies, the parts of the body are no longer able to perform their functions and fall back into just being clumps of matter, rather than, say, an eye or a finger or a hair.
Because our machines do not have souls, their individual parts do not act as a unified whole; the parts are not coordinated in their activity by an immaterial principle. When a computer is functioning, each of its parts is merely doing what it is in its nature to do and which it would do in any other context. The keyboard, CPU, and screen of a laptop computer, for instance, do not belong to a single organism; they only have an accidental connection to one another.
That being said, human designers of computers try to make the parts of laptops be at the service, as much as possible, of a single purpose that is outside of those parts. Because the parts are merely material, instead of being living, they are completely passive to whatever we do to them. As such, we are able to go quite far in making it seem, in our most sophisticated machines, as if they have a purpose intrinsic to themselves—as if they have a soul.
This is made possible especially by the mimicking of sensing and thinking, operations which only living things can do. Machines are not able to sense; they are not able to experience, for instance, the hearing of sounds. They are, however, able to record them. That is, they are able to take a physical sound wave and convert it into a digital file that is stored on physical media or is input into a computer program.
Machines are not able to abstract universal being from sense data; they are only able to associate words with one another that have been input via keyboards or stored on physical media. They are not able to make judgments by affirming or denying something about reality; they are only able to perform a sequence of operations that they have been pre-programmed to execute when receiving a given prompt, which operations yield a string of characters that they do not understand but which resemble a human judgment.
But when a computer records the sound of a human voice saying, “Could you give me a rundown of well-authenticated Eucharistic miracles of the past 60 years?” and then runs a program which parses that sound, looks up a pre-programmed response for the parsing, and responds with a computer voice in the English language giving a detailed answer to the question—in a situation like this, the computer seems to be thinking. It seems to understand human language, to be able to reflect, and to be able to formulate answers in a living mind. This is all the more true if the computer is not a smartphone, but a robot that has been made to physically resemble a human being.
It is all only an appearance, however, because the processes that led to the sounds of the answer being made were strictly material. At no point did they ever rise above the level of purely material, soulless events.
To summarize, humans have a conscious, experiential, living, holistic, thinking interaction with reality, while machines only have an unconscious, unfeeling, unthinking, sequential interaction with reality. Yet they do have the capacity to imitate human activity, by means of a highly complex juxtaposition of parts, extremely rapid mechanical operations, and very sophisticated input.
Endnotes
1 I, q. 79, a.1.
2 I, q. 79, a.2.
3 The Realist Guide to Religion and Science (Gracewing, 2018), 8–9.
4 William Wallace, The Modeling of Nature (The Catholic University of America Press, 1996), 150.
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