Substance and accidents


As I was in adoration contemplating the mystery of our Lord’s eucharistic presence, I began to wonder.

I know that the eucharist is really his actual body and blood, soul and divinity.

I once heard a priest say something about being careful about what we infer about the physicality of what that means.

I know that that we are created a body/soul unity, which I guess means that “fleshiness” is of our substance. But that doesn’t necessarily mean that this physical thing tapping at the keybord is essential to me. Chop off any number of pieces of my body and I’m no less me – so it would seem that this thing that I experience as “my body” is accidental, and yet substancial to us is that we are flesh.

So perhaps one might say (and I find it VERY disturbing to write this) that in this physical thing sitting at my desk one encounters the body, blood, soul and humanity of neophyte, hidden in the accidents of a 5"10", 155 lb man with brown hair.

Oy. I feel like just I wrote something blasphemous. But I also felt that way when I began to talk to our blessed Mother, so…

Your thoughts? Anyone know if any of the Fathers or Doctors of the Church have written about this? Is this within the bounds of permissible Catholic speculation?


Yes, from a philosophical point of view that sounds right. No one can actually directly perceive your substance–except your guardian angel and God. Someone can only perceive you through what comes into their senses. The description you give is what I would see provided my senses are operating correctly. But a Martian whose eyes were sensitive to an entirely different electromagnet spectrum and who had different types of senses, would perceive you quite differently.

The point is, neither of us can get at your essence; we are totally dependent on what comes in through our senses. This, Aquinas would call the “accidents.”


I don’t think you’ve written anything blasphemous - at least not as I understand what your post says. The size, weight, skin color, odor,… are all “accidents” of the physical “substance” of your body.

In reference to the union of your body and soul, two questions could be posed:
What are you? A human being.
Who are you? (your name)_ (a “person”)

“Personhood” is still one of those big question marks in philosophy as far as I know. Not a whole lot out there about it.

If you haven’t read the Catechism of the Catholic Church #362-368, you might find that informative.



First off, let’s make sure we don’t fall into dualism–your body and soul are both your person–even the souls in Heaven are not “complete” until the Resurrection of the Body. Your Body is you as much as your soul–ok, thinking about that makes my bain hurt :stuck_out_tongue:

Let’s also remember, the Eucharist is a great mystery that cannot truly be comprehended and put into words. The Council of Trent taught us beautifully this truth:

“In the first place, the holy Synod teaches, and openly and simply professes, that, in the august sacrament of the holy Eucharist, after the consecration of the bread and wine, our Lord Jesus Christ, true God and man, is truly, really, and substantially contained under the species of those sensible things. For neither are these things mutually repugnant,-that our Saviour Himself always sitteth at the right hand of the Father in heaven, according to the natural mode of existing, and that, nevertheless, He be, in many other places, sacramentally present to us in his own substance, by a manner of existing, which, though we can scarcely express it in words, yet can we, by the understanding illuminated by faith, conceive, and we ought most firmly to believe, to be possible unto God.”

Remember, “sacramentally present” means “mysteriously present” as “sacrament” comes from the Latin for “mystery.”



I don’t think your statement is remotely blasphemous. :slight_smile:

Basically, that a human person is a body and soul is essential, and my substance is body and soul. That my body is 5’ 7", pale, and has a red beard is accidental to my substance.

Now this pale, red-bearded body IS me, truly and completely, but that I have this or that physical feature is indeed accidental. The example used above of a Martian with a different set of senses (for example, x-ray vision) is very good at illustrating this, IMO.

To understand why it’s important to assert this, it may help to think of the alternatives given our knowledge of our bodies. If these physical traits, i.e. that this or that color, or even this or that atom, were essential to my substance then I would not be the same person from moment to moment. You see, every second a chemical change takes place in me: some cells die, new oxygen atoms are brought into me and old ones are expelled, my food is broken down and built into new cells to replace the old ones, and the movement of electrons in my brain changes constantly. If these things were the substance, and not the accidents, then I as a continuing being do not exist; I’m just a collection of moments lumped together under an arbitrary heading of “individual”, despite the fact that none of those moments is really the same.

So in every moment my accidents change, but my substance does not. I have new atoms, I literally have new flesh from moment to moment, but who and what I am remains the same. That is why I can speak of myself at all. As one of my Dominican theology teachers put it, if substances were their accidents then we couldn’t even jump in the same river once. :wink:

The Mississippi River is not the same water molecules from moment to moment, but it’s the same river. While it’s substance is that of a river, which means that substantially it must be “flowing water”, that it is composed of this or that particular water molecule is accidental. So saying that the water molecules are accidental to the Mississippi River in no way means that the substance of the Mississippi River could be something other than “flowing water”. We could even say that when there were no water molecules, there is no more Mississippi River. Make sense?

What occurs in Transubstantiation is miraculous, because one substance (Christ) takes on a new set of accidents. While they are definitely accidents (the accidents of bread and wine), if they were no longer there then Christ would not be there (which is why we say that Christ is no longer present when the Eucharist spoils and becomes something other than bread and wine). Nothing else in the universe undergoes such a radical change of accidents, in which the substance of one thing is utterly replaced by the substance of another without destroying its accidents.

Hope that helps!

Peace and God bless!


Oh, no risk of that, I’m clear on the body/soul unity thing but thanks for the reminder.


Thanks, Ghosty. I’d heard something similar to what your instructor said, but had forgooten about it.

I just happened to be reading Athenagoras’ Plea to Emporers Antoninus and Commodus, in which he says “Rather did the Son come forth from God to give form and actuality to all material things, which essentially have a sort of formless nature and inert quality, the heavier particles being mixed up with the lighter…”

I think that this touches on the difficulty I’m having. The essence of a river is to be flowing water, and as the actual molecules are accidental to the river so (it seems to me) is the form of the river, it’s shape, the path of it’s bed and such. So although the river is essentially material (flowing water), it is also essentially formless as Athenagoras said. And this would be the case for you and me as well.

Essential to being a human being is that we have consciousness, self-awareness, and yet at the moment of my conception I apparently had neither. So conciousness is substancial to me, and yet whether or not it’s actualized is accidental?

Assuming I’ve got this right, it’s quite an incredible mystery. Hey, even if I hav it wrong (moe likely) it’s quite an incredible mystery.


:slight_smile: And I thought it was hard enough to jump in the same river twice!

What occurs in Transubstantiation is …Nothing else in the universe undergoes such a radical change of accidents, in which the substance of one thing is utterly replaced by the substance of another without destroying its accidents.

It may help to remember, in keeping with this vein, that matter is potential to form; so the “enmattered” finger now typing, is not matter itself, but matter actualized by that form which is my particular soul, the soul being the act of the body. Such that, the matter and soul together make a human being (so that, when we get our bodies back in heaven we will truly be “ourselves” again). The substance underlying matter–“prime” matter–has no accidents, no qualities.

So in Transubstantiation, the substance which underlies the enmattered bread and wine is replaced by the substance which underlies Christ’s glorified Body. It is a beautiful miracle even in these philosophical terms!


I sat down here with a peanut-butter sandwich thinking that I had something to chew on. WRONG!

toaslan, I’m gonna have to print this out and meditate on it for a while. Thanks!

closed #10

DISCLAIMER: The views and opinions expressed in these forums do not necessarily reflect those of Catholic Answers. For official apologetics resources please visit