How do I know I’m not a brain in a vat?

 T image of the brain in the vat-quite apart from what Putnam actually intended it to do- is used as simply another presentation of the foundational challenge of modern philosophy: how do you know that you know? How do you rule out that you are a brain in a vat? We can imagine this being the case, so it must at least be possible…right?

No! No! Ten thousand times no! Our imagination, whether taken narrowly or broadly, is neither the measure nor the cause of any real possibility. There is no relation between imagination and real possibility: some imagined things are possible, others impossible, others necessary; and the same is true for those things that cannot be imagined. As soon as we allow that our imagination indicates real possibility, we allow a parallel universe of possible beings that are evident to imagination alone, and whose real existence does not follow from actual external sensation.

This kind of argument is not philosophy, but precisely the sort of thing that philosophy seeks to avoid- namely spellcasting and shamanism. The power one feels in the brain in the vat argument is the exactly the same power that voodoo witch-doctors use to cast hexes, because whether one falls prey to a hex or the BIV argument, the mechanism is the same- we think some thing is a real possibility to be feared, fought against, or even accepted simply because we can imagine it being so. How can we rule it out? Maybe we aren’t wholly convinced by the argument/spell, but isn’t it better to assume it is true just to be safe? After all, the most reputable people in the village/campus think it’s so.  

How do I know I’m not a BIV? It’s not because “this is my right hand, this is my left”; or because realism is a more effective practical postulate; or because the BIV offends my intuitions; or because I ignore the question (and it is a real question that deserves a response. I call it shamanism in all respect. Shamanism has real power). I know I am not one because I have not set up imagination as indicating real possibility.

The Doctrine of Analogy

On the one hand, St. Thomas opposes the analogous names of God to names that are said by way of causality or negation; and on the other hand he opposes an analogous name of God to names that are univocal or purely equivocal. This means that there is a double answer to the question of whether we know God by analogy. Taken in the second sense, the answer is “yes, and only by analogy”. Taken in the first sense, the answer is “yes, but only because we know him by way of causality”.

The question of analogy in the divine names first comes up when St. Thomas asks whether we name the substance of God. The obvious first answer is “no” because we don’t know the substance of God. St. Thomas concedes that we don’t know the substance, but he still argues for how we can’t account for what we say about God merely by way of causality or negation. In other words, because naming God by causality and negation is not enough, we must also name God analogously. The critical thing to notice here is that even if one denies analogy in this sense, he still has a perfectly robust natural theology, and can prove God’s existence and speak of his attributes just fine.

In the second sense of analogy, to deny analogy is to deny knowledge of God altogether, for one either places God in a genus (univocal naming) or he says that all names are said of God and creatures by complete chance (pure equivocation). The important thing to notice here is that when this question comes up, St. Thomas has already shown that we have to speak about God analogously in the first sense we spoke of above. If St. Thomas had not proved the first sense of analogy, he would probably speak of How we name God neither univocally or purely equivocally, but causally or negatively.   

Objections to immaterial beings, part II.

On the one hand, the human mind must base all of its knowledge on sensation, but on the other hand, we distinguish sense knowledge from intellectual knowledge. To be more precise, we would have to distinguish even among sense knowledge, we can distinguish the exterior senses- like touch and sight and hearing- from the interior ones, like imagination. When we speak of all our knowledge being based on sensation, we mean it takes its origin in the exterior senses.

But though our knowledge arises from exterior senses, our judgments about the things we know are not always judgments about things given in exterior sensation. This is obviously true in the case of fictional characters- our opinions about Hamlet or Don Quixote are not judgments about actual persons given in sensation, which is why we don’t call the police when Hamlet kills Leartes. But this is no less true of rigorous scientific entities- like mathematicals. Even if every orbit and fragment of projectile motion failed to be a perfect ellipse, it would not change the definition of the ellipse- or any of the proofs that follow from the definition. Even though we take our knowledge of mathematicals from sensation, no mathematical entity is perfectly given in sensible things. In St. Thomas’s terms, mathematical things are taken from sensation, but terminate in the imagination. Said in our terms, although our knowledge of mathematical things comes from our exterior sense experience (because we could never know them without sight or touch), our judgment about mathematical things is not a judgment about something in exterior sense experience, but about something in imagination. We give a similar account of fictional characters, groups and classes of individuals, hallucinated beings, etc. In fact, the ability of something to be in imagination that is not in sense is a major cause of error and even psychosis. There is no error in dreaming, but there is in believing that the things we dream are given in exterior sensation. A similar account can be given of some psychiatric disorders, or errors.

This distinction between things terminating in exterior sense and those terminating in imagination provides us with a light to see the even more important distinction between those things that terminate in sensation, and those that terminate in intellect. Our judgments about things given in divine science are given neither in exterior sense nor in imagination, even though our knowledge of these things takes its origin in things we know from sensation. Our inability to sense those mathematicals we imagine is an analogy for our inability to imagine those things we judge to exist by intellect. One cannot see or touch any of Euclid’s circles, but he can imagine them; and in a similar way one cannot imagine his own soul or agent intellect, or universals, or the angels, and yet they are known. The kind of knowledge we can have is radically imperfect- for notice that even though we imagine mathematicals, there would be no impediment to our actually sensing them: we could touch Euclid’s triangles if such things existed. Nevertheless, we could never sense universals, even if they existed outside of our minds- neither will we ever be able to look at the angelic nature even though it does subsist outside of our mind.  The knowledge we have of the things that terminate in intellect alone is taken by separationfrom the things in sensation. This separation happens either by a direct negation of the things given in sensation- which gives us concepts like immaterial, or by way of showing the loftiness of things above sensation. If we visualize our knowledge as a line that goes from A to B, with A being exterior sensation and B being intellect, we can imagine metaphysics as either about the “not-A”, or the “above A”, but we can never have a perfectly clear, distinct third concept of “B alone” (if one posited imagination [X]on the line between A and B, he could, on the contrary, speak of an “X alone”, which is why one does not need to define mathematicals by either negation or excellence.)

Objections to immaterial beings, part I.

I tend to hear two objections to the existence of immaterial things:

1.) Immaterial beings are unnecessary hypotheses

2.) Immaterial beings are unthinkable.

The first objection can’t be solved without some knowledge of the different methods of proof; and in light o this problem we most of all need to distinguish between a.) results that prove principles and b.) principles that prove results. The first kind of method begins with a hypothesis, the second kind doesn’t- and can’t. So far as one tries to start with the hypothesis of an immaterial being, he is almost certainly doomed, because then he must also lay down material beings as a contrary hypothesis, and insofar as we take material beings as hypotheses, we are agnostic about he extent and reach of their powers- we just have to wait and see what they can do. The one who looks a material beings in a hypothetical light can always imagine some day when matter will explain intentions or morality or universals or purpose, etc, and so far as he sees matter hypothetically there is no reason for him not to imagine this.

Notes on Matter and Body

-The distinction between matter and body is important, but rarely distinct. Bodies are evident to us, but matter or materials are what bodily things are made of. Materials might often be bodily things themselves, but to be material is not the same thing as to be a body. Matter stands to body as parts stand to a whole.

-Materialism is probably better called corporealism- the idea that all that exists is a body. We call it materialism because it lays down matter as the only principle of things- but whenever we jumble the difference between things and their principles we end up with an infinite regress to dissolution.

-St. Thomas’s account of the history of philosophy is almost always the same, and it usually begins with him saying

Primi enim qui naturas rerum considerare incoeperunt, imaginationem transcendere non valentes, nihil praeter corpora esse posuerunt…

The first ones who began to consider reality- not being strong enough to transcend imagination- set down that nothing existed except bodies…

-We start off by knowing bodies, and we come to know matter by breaking up the body into smaller parts. This analysis of a whole sometimes involves throwing out the whole when we find the parts, and sometimes not. An analysis of air shows that it is better understood as a multitude of things, but an analysis of water does not- or at least the analysis of water shows it has a certain real unity that air lacks. The thing we call air can really be reduced to its component parts, and so after we analyze to we throw out the idea of some single gaseous mass called “air”. Air has (at best) an operational unity- but water has a real, natural unity. If our analysis of water led us to say that it was “nothing but” its component parts, we would destroy the whole idea of a molecule (water) as opposed to a bunch of atoms (air), which would not be an advance in knowledge, but a regression.

-Matter is on the one hand a primary thing; and on the other hand, incomplete, and ordered to another.

-If we paid attention to how we come to the idea of matter either from looking at the material of the things we make, or  by looking at the proximate pars that make up certain wholes, one of the first things that we wuld conclude about matter is that it is for the sake of something.

-Matter is to body as potency to act. We think of the materiality of elements when we want to dissolve the thing into what is “really there”, but we think about the corporeality of elements when we want to make them really there.

-Our knowledge of matter is a proof that we can know something other than bodies. Our knowledge of natural bodies is a proof that we cannot reduce them all to matter.

The “Horse’s Head” argument

Aristotle claims that all necessary arguments are syllogisms, or reduce to them. One objection to this- which has bothered me for years- was the “horse’s head” objection, namely:

A horse is an animal.

therefore the head of a horse is the head of an animal

From a single premise, one draws an absolutely necessary inference from relations that belong to both terms in the premise.

I stumbled on the response to the objection yesterday in an introduction written by Richard Berquist to the Commentary on the Posterior Analytics. His claim, which I find convincing, is that though the horse’s head argument is a necessary inference, it’s not a proof or even an argument, for it provides no evidence or reason for the conclusion. If someone were in doubt about whether the head of a horse were the head of an animal, then to tell them that a horse was an animal would neither convince them of anything, nor provide any evidence. This becomes more clear if we appeal to a disputed case: someone who is in doubt about whether the stem cells of a blastocyst are the stem cells of a person, for example, receives no evidence or even argument from one who says “every blastocyst is a person”.   

Science and the Immateriality of the Intellect

St. Thomas usually supports the first argument for the immateriality of the human intellect by using an example from the science of his time:

 It must necessarily be allowed that the principle of intellectual operation which we call the soul, is a principle both incorporeal and subsistent. For it is clear that by means of the intellect man can have knowledge of all corporeal things. Now whatever knows certain things cannot have any of them in its own nature; because that which is in it naturally would impede the knowledge of anything else. Thus we observe that a sick man’s tongue being vitiated by a feverish and bitter humor, is insensible to anything sweet, and everything seems bitter to it. Therefore, if the intellectual principle contained the nature of a body it would be unable to know all bodies (ST I q. 75 a. 2.)

The same argument, however,  can be supported by any scientific account of sensation. If one holds that eyesight is caused by an electromagnetic impulse, then if those same electromagnetic impulses all of a sudden became part of the constitution o the eye, then we would either see spots, or a jumble of things. Either way, our sensation would be harmed. In fact, if this condition of random electromagnetic stimulation of the eye arose in us spontaneously, we would consider it a disease, just as St. Thomas considers suffering under “feverish and bitter humors” a disease. Similarly, if the same sort of percussion waves that cause hearing arose on their own from some part of the ear, we go to the doctor to see what was wrong with our ears. The analogy holds just fine to the mind: if the same sort of bodies (or powers of bodies) that cause our knowledge were within mind as parts, then there would be something wrong with our mind. If mind is the activity of some organ, like hearing is the activity of that organ that goes from the auditory canal to the cochlea, then this organ of mind must have no physical parts.

Note carefully that the proof is not saying “What Knows X lacks X”- in that case the mind would not exist, because it know existence. The proof is rather that if the mind is a bodily organ (or the act of one) and therefore having bodily parts by nature within it, it would not know bodies. But the consequent is obviously false- in fact, the consequest must be considered false especially by a strict materialist! Even more, if mind were a bodily organ (or the act of one) and therefore having bodily parts, it would have to be by nature broken and diseased- just as a man’s ear would be diseased if it had a part that started emmiting a percussive sound wave. 

Thought on the history of philosophy II

One of the clearest, most consistent, most uncompromising and emphatic beliefs of Martin Luther was his rejection of metaphysics. In defining the Reformation, Luther raised the rejection of metaphysics to a religious doctrine. Later rejections of metaphysics by philosophers writing centuries later are all derivative, and presupposed that religious sentiments had already done most of the destruction. Kant was right to point out that metaphysics was once the queen, but was cast down like Dido: but she wasn’t deposed by reasoning, but by religion.

The First Way

1.) One cannot explain why a body is in motion by positing some bodily cause. All this does is create a bulkier, still unexplained body in motion.

2.) Confronted with this, the mind naturally posits forces or powers that move the body (like gravity and inertia), but are not bodily themselves.  

3.) These forces either subsist in bodies, or apart from them. If within, one simply ends up back in step #1- the force is just one more thing in motion. Gravity and inertia are examples of such forces- for they are defined in relation to bodies. So too, a fortiori, are all the forces of magnets or electrons or radioactive decay.

4.) So the force must subsist outside of bodily, material existence. This means it is an immaterial subsistent and operating being- said in a word, a spirit. To understand this involves the mind ascending first of all to what all call God, for we can only understand intermediate or subordinate spirits (like angels, say) as intermediaries.

The Memory of Meditation Two.

The still of the room

Warmly dim and stale from throaty wax,

burned with pollen flowers yesterday-

to show his hands were nothing,

nor the page,

that pulled and dragged and scratched upon his


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