One of the most common arguments from atheists is that matter is all that there is, and that the immaterial (God, angels, the human soul, etc.) simply doesn’t exist. This position is generally called “philosophical materialism,” although that term encompasses a number of distinct positions. In any case, here’s one of the clearest presentations of this argument:
When we speak of immaterial things, we are speaking of something that has no physical substance. Now, if you think about this, everything we know to exist has physical properties. Your arm, leg, mind, blood, teeth, tongue, and everything else are physical. They are in the form of your physical body. Your brain can’t work without physical/material processes of chemistry and electricity. Electricity can’t work without the physical electrons. A windmill can’t work without the physical air that passes across its blades. Everything we know to exist is physical.[….]
So, if God is not material, what is God? If there is no answer for what God is, all we can say is God doesn’t exist, or he exists nowhere and is comprised of nothing, which I don’t see how that isn’t the same exact thing. It is rather interesting how the theist description of what there God is actually puts their God out of existence.
Or, a shorter version of essentially the same argument:
If we are talking about immaterial existence, then there is nothing to differentiate an entity or “thing” which exists from one which does not exist.
Often (including in the second link provided), these discussions descend into debates over speculative science: whether or not dark energy or photons have mass, etc. But I think that this materialist argument can be answered easily, using agreed-upon evidence. In other words, the fact that the universe is made up of something other than matter is self-evident, and should be admitted by anyone, upon close reflection. In addition to matter, we also see immaterial forms that can dictate the nature and behavior of the matter itself.
We can observe forms in nature, and cannot account for them in purely material ways. This is true even of forms that cannot exist apart from matter. Consider the following examples, from most to least technical:
- Isomers: This is my favorite example. When two or more (different) compounds share the same molecular formula, you have isomers. For example, there are three different compounds with the molecular formula C3H8O: methoxyethane (a colorless gas that is extremely flammable and reactive); propanol (a liquid solvent used in the pharmaceutical industry); and isopropyl alcohol (rubbing alcohol).
These are different substances, with different chemical properties. Yet these differences are not material. They’re formal. That is, each of the three substances is made up of the identical atoms: 3 carbon, 8 hydrogen, and one oxygen. It is the arrangement of those molecules that determines whether the substance will be methoxyethane, propanol, or rubbing alcohol. The same matter, in different forms, produces different substances.
- Phase Changes: A more obvious example of this would be the phase changes of water. Depending on its form (solid, liquid, or gaseous), it exhibits different properties, and is structured differently. Yet it maintains the same molecular and structural formula.
- Surfaces: The surface of a table is not the table itself. Surfaces are immaterial, and have no mass, and occupy no three-dimensional space. If you doubt this, try to imagine a surface that is 3 feet deep. Whatever you are visualizing is not a surface, but a substance with surfaces of its own. But we can still observe that surfaces exist.
- Shapes: Envision two different objects of equal mass, made of identical materials. The first is a wooden cube, and the second is a wooden sphere. The difference between the two objects wouldn’t be material, but formal.
In each of these cases, the form itself is immaterial. To test this, take your wooden objects, and remove the matter that they have in common (the wood). Likewise, take your isomers, and remove the matter that they have in common (the carbon, hydrogen, and oxygen). The result will be the same: you will be left with nothing. But does that mean that the different objects were, in fact, the same? Of course not. It means only that, in each of these cases, differences exist between the substances, but these differences cannot be isolated by removing the material common to each. That’s because these differences are immaterial, rather than material.
Those cases are obvious enough. A less obvious, but dramatically more important, example of a perceivable form is life itself. Consider what philosopher Peter Kreeft fittingly named the “Dead Cow Argument”: you come across two cows — one that is alive, and one that has just died. What is the difference between these two cows? Craig Payne, quoting Kreeft, explains:
There appears to be no material difference (e.g., in size or weight or color) between the two cows. Yet something is clearly missing. What is it?” The obvious answer is that the cow is “clearly missing” its life – its “soul” or anima, in other words, its animating principle or form, that which causes the cow to live and develop as a cow.
So the living and the dead cow, at this point, are still materially identical. Nevertheless, we can immediately observe that an immaterial difference exists, and a radically important one. As Kreeft notes, both cows have air in their lungs, but only one can breathe. This distinction is, as noted above, the “animating” principle of the matter: the form enabling a particular material substance to live. It is from this that we have the simplest understanding of what a soul is: the animating principle of a body.
Certainly, this is only the beginning of a discussion on the soul, not the end. We’re still left to determine what sort of a thing the immaterial soul is, whether a human soul is like a cow soul, and so on. But this line of reasoning does dispel the absurd notion that the material is all that there is.