Some notes from J. P. Moreland’s excellent book, The Soul: How We Know It’s Real and Why It Matters (Chicago: Moody Press, 2014).

What is dualism?

The view that the soul is an immaterial thing different from the body and brain.

What is substance dualism?

The view that a human person has both

  1. a brain that is a physical thing with physical properties, and
  2. a mind or soul that is a mental substance and has mental properties.

What is Thomistic substance dualism?

The view that the (human) soul

  • diffuses,
  • informs (gives form to),
  • unifies,
  • animates, and
  • makes human

the (human) body.

The body is not a physical substance, but rather an ensouled physical structure such that if it loses the soul, it is no longer a human body in a strict, philosophical sense.

What is the soul?

  • The soul is a substantial, unified reality that informs (gives form to) its body.
  • The soul is to the body like God is to space—it is fully “present” at each point within the body.
  • The soul and body relate to each other in a cause-effect way.

Do animals have souls?

Yes, animals have a soul. But an animal soul . . .

  • is not as richly structured as the human soul
  • does not bear the image of God
  • is far more dependent on the animal’s body and its sense organs than is the human soul.

What are four arguments for substance dualism and the immaterial nature of the soul?

1. Our basic awareness of the self

  • We are aware of our own self as being distinct from our bodies and from any particular mental experience we have, and as being an uncomposed, spatially extended, simple center of consciousness.
  • This grounds my properly basic belief that I am a simple center of consciousness.
  • In virtue of the law of identity, we then know that we are not identical to our body, but to our soul.

2. Unity and the first-person perspective

  • If I were a physical object (a brain or body), then a third-person physical description would capture all the facts that are true of me.
  • But a third-person physical description does not capture all the facts that are true of me.
  • Therefore, I am not a physical object. Rather, I am a soul.

3. The modal argument

  • I am possibly disembodied (I could survive without my brain or body).
  • My brain or body are not possibly disembodied (they could not survive without being physical).
  • Therefore, I am not my brain or body, I am a soul.

4. Sameness of the self over time

  • A physical object composed of parts cannot survive over time as the same object if it comes to have different parts.
  • My body and brain are physical objects composed of parts that are constantly changing, and therefore cannot survive over time as the same object.
  • However, I do survive over time as the same object.
  • Therefore, I am not my body or my brain, but a soul.

What is the relevance of neuroscientific data to whether or not we have a soul?

Neuroscience is a wonderful tool, but it is inept for resolving disputes about the nature and existence of consciousness and the soul. The central issues in those disputes include philosophical, theological, and commonsense topics. Neuroscientific data are simply irrelevant for addressing those topics.

Neuroscience shows correlation between mind and brain, not that mind and brain are identical.

How is the law of identity relevant to this relationship?

Leibniz’s law of the indiscernability of identicals states that for any entities x and y,

if x and y are identical,

then any truth that applies to x will apply to y as well.

Some things are true of the mind or its states that are true of the brains or its states; therefore, physicalism is false and dualism (provided it is the only other option) is true.

What are the states of the soul?

Just as water can be in a cold or hot state, so the soul can be in a feeling or thinking state.

Here are five such states: 

  1. sensation: a state of awareness, a mode of consciousness (e.g., a conscious awareness of sound or pain)
  2. thought: a mental content that can be expressed as an entire sentence and that only exists while it is being thought
  3. belief: a person’s view, accepted to varying degrees of strength, of how things really are
  4. desire: a certain inclination to do, have, avoid, or experience certain things
  5. act of will: a volition or choice, an exercise of power, an endeavoring to do a certain thing, usually for the sake of some purpose or end

What are the faculties of the soul?

The soul has a number of capacities that are not currently being actualized or utilized.

Capacities come in hierarchies:

  • First-order capacities (e.g., I have the first-order capacity or ability to speak English)
  • Second-order capacities to have first-order capacities (e.g., I have the potential to speak Russian, though it is not actualized)
  • And so forth

Higher-order capacities are realized by the development of lower-order capacities under them.

The capacities within the soul fall into natural groupings called faculties. A faculty is a “compartment” of the soul that contains a natural family of related capacities. For example: 

  1. Sensory faculties
    1. sight (All the soul’s capacities to see are part of the faculty of sight. If my eyeballs are defective, then my soul’s faculty of sight will be inoperative just as a driver cannot get to work in his car if the spark plugs are broken. Likewise, if my eyeballs work but my soul is inattentive—say I am daydreaming—then I won’t see what is before me either.)
    2. smell
    3. touch
    4. taste
    5. hearing
  2. The will: a faculty of the soul that contains my abilities to choose
  3. Emotional faculties: one’s abilities to experience fear, love, and so forth
  4. Mind and spirit
    1. Mind: that faculty of the soul that contains thoughts and beliefs along with the relevant abilities to have them
    2. Spirit: that faculty of the soul through which the person relates to God (Ps 51:10; Rom 8:16; Eph 4:23) [prior to regeneration, most of the capacities of the unregenerate spirit are dead and inoperative; at the new birth, God implants new capacities in the spirit]