Brain Damage and the Soul

So recently something has been troubling me.

All Christians believe there is a soul.And the soul is in a way seperate from the brain.

It is a seperate substance to be exact.

But the thing is,even though the soul is seperate from the brain,brain damage has been prooven to have the ability to change things.

Things from people’s personalities,their behaviour,political beliefs,daily patterns,their attitude and even their entire ‘‘person’’ so to say.

For example,many people say that when they were removing tumors or had certain medical procedures be performed on their brain,they left the procedure a completely different person then they were before.

Another example is Phineas Gage,who after a railroad accident where a metal pole went through his skull,had a completely changed personality and attitude.

His mental abilities and IQ were all unchanged,but his personality completely changed.

It has also been known that certain damage to brain tissue can also cause changes in a person’s moral judgement.

The thing that troubles me is this:

If the soul exists and is a seperate entity or substance from the material brain,then how come brain damage or simple neurological procedures can create either small or massive and complete changes in personality,certain moral intuitions and even political ideologies?

When a person has mental illness or damage to their brain they are either less culpable and sometimes completely without blame for certain behaviors that they may exhibit. That is why no one can judge rightly except God.

For example, some people see others behavior and say, “Joe is lazy.” but that may not be the case in reality. There may be underlying medical and mental reasons for why a person behaves the way they do.

I don’t think is correct that the brain is separate from the soul, at least not for catholics. The idea that brain and soul are separated goes into the theory which says that soul and body are two separate entities and that is not a catholic belief, so it may be a belief of some protestants or evangelucals but not a catholic belief at all. For catholics body and soul are one entity, they are not separated. Body and soul are united in one, hence the reason why brain damage can cause severe changes to a person’s personalities. The brain as part of the body is also united with the soul on the same way that the rest of the body and the soul are one.

If you have an injured limb, your ability to move is impaired, although movement originates in the soul (anima --------> animation).

Likewise, an injury in the brain affects knowing and behavior, although both originate in the soul.


Wow, great question! Never thought of this before. Seems quite scary especially if you are quite holy before the procedure/accident…and the complete opposite afterwards.:eek:

We are a union of body and soul, in Catholic teaching.

I don’t know whether the soul = the consciousness. Consciousness may be a limited manifestation of your immortal soul, or an element of the soul, but I don’t think they are exactly the same. Consciousness (that is, your day-to-day internal experience of reality) might be the stepped-down activity of your soul, as regulated by your brain, as James suggested - the brain may function as a step-down valve for the governing soul. The full awareness your soul will experience after the death of your physical body might not be possible to experience in our current bodies. Perhaps after the Second Coming, our new bodies may be capable of full communion with the soul. Perhaps our current situation is an consequence of the Fall.

Consciousness affects the body. If you are happy, said, tired, depressed, excited, it will be observed in the attitude of the body, everything from posture to the degree of muscle activation to tears to your resistance to disease.

Likewise, the body affects the consciousness, and by extension, your soul. Break a leg, and it has an effect of your consciousness. Joyous sex with your spouse has an effect on your consciousness. Degrading, loveless sex has an effect on your consciousness. A hug from your daughter has an effect on your consciousness. Contracting cancer has an effect on your consciousness. This is one of the reasons that what we do, or shouldn’t do, with our bodies matters.

The effects of trauma to the brain, whether it be Alzheimer’s, traumatic brain injury, mental retardation, schizophrenia, stroke, or other causes, will effect the consciousness, that is, how the brain processes the directives of the soul, but the soul itself is not damaged or truncated. I think God will take those factors into account, as we are all not born into the same set of circumstances and some will have a greater cross to bear than others.

The soul is not consciousness. The soul is life.

If you become unconscious, your soul remains; when you will be dead, your soul will have left.

Consciousness is a process, that in human life, requires the soul, but is mediated by the breath in our bodies, through various mechanisms in our heads.


Aquinas refers to man as a composite being. It’s difficult to separate spirit from body, they are intertwined. We exist partly in the material realm as well as the spiritual realm. I sort of think, though this is my own view and may be incorrect, that we are part animal and part angel in a fashion. We have certain principless of each species.

As far as the soul or spirit goes, it is the principal that gives life to the body.

Once we die, our souls will be separated from our bodies for a time. You can see this in NDE’s. This is just a temporary thing until the Last Judgement at the end of time when we get our bodies back, a glorified body in Heaven.

A person who has behaved badly in some ways due to brain injury or brain illness of some kind will not act that way in Heaven if that is their destination.

Have you heard how some people as they get quite old change seemingly for the worse and use terrible language. That is dementia in the brain. It is not who they are as a person.

Only God can look upon the deepest aspect of a person, their heart, and from that, he will judge us. Illness and injury cannot change the heart of a man, I believe, though on the outside to us it may seem that this has been the case.

I am not sure if this applies to the question but thought this article was interesting. See attached

Alcohol changes people’s personalities, too, as do blood-sugar levels, degrees of tiredness, and age. The personality is not the soul.

As regards the particularly moral issues, there are very few psychological conditions under which the person loses free will. The drugs, the mental illness, or the brain damage almost never make a person act in a certain way; they just predispose the person towards certain feelings which might prompt but very rarely force certain behaviours. Thus, for example, humans are naturally engineered (i.e., hormonally driven) to be sexual creatures, but two thousand years of church history has adequately demonstrated that it is possible (albeit not easy) for humans to be live voluntarily celibate lives.

For someone with a brain injury, or a mental illness, avoiding certain behaviours may be more difficult than it is for other people, but it is still almost always possible. Thus, the injury or illness can act as a sort of a moral handicap, but so can a lot of other life conditions. We just have to learn to do what we should even when we do not feel like it.

The notion that the soul and the body are separate is the problem, and this is NOT Catholic teaching.

We know from Jesus that the soul and the body are forever linked. You cannot have one without the other. They cannot be separated. When Jesus returned, he returned with his body. This is why it is important to understand that when we receive Jesus in the Eucharist it is also his body. He cannot be separated.

So it is for us too.

So when the body is injured, or the soul is injured, the whole being is affected.

Hi NormalBeliever,

Excellent question! I’m gonna take a crack at it:

There’s a distinction between soul and mental / cognitive abilities. For instance - a mentally challenged person may have reduced mental abilities, but that doesn’t mean they have a lesser soul. Your soul is you, but the spiritual side of you. The material side of you is your body. Your consciousness resides in the soul, but your mental abilities reside in the body (namely the brain).

Keeping that in mind - if I perform an experiment to alter someone’s brain to change their personality, or political ideals, etc, I am NOT manipulating their consciousness but rather manipulating their brain and mental abilities. The consciousness then observes this change and makes decisions accordingly.

Another way to look at it: If I change someone’s brain so that they see red instead of blue and visa versa, their opinion on the observations of the external world would change. But the consciousness is unaffected. It is still making decisions, it’s just the information it’s receiving to make decisions has changed.

Hope that helps!

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