Maverick Philosopher

Berkeley's Unperceived Table

Ed writes,

A question: if Berkeley is out of his study, and says ‘My table is in my study’, is he speaking truly or falsely? If truly, then ‘my table’ and ‘my study’ must have referents, and the referents must stand in the relation ‘in’. But neither referent is perceived, so neither exists, according to B’s first definition of ‘exist’, and so ‘My table is in my study’ is false. According to B’s second (counterfactual) definition of ‘exist’, the statement can be true, but then we have to drop the first definition. Then what else do we lose of B’s philosophical system?

For example, is the statement ‘the table in my study is brown’ true or false, given that if B were seeing the table, he would perceive it to have the sensible quality of brown, and given that B is now outside his study? If true, then he must concede that the referent of ‘the table in my study’ is bearing the visible quality signified by ‘brown’, and so concede that everything he says about the impossibility of material substance is wrong, e.g. in §9 of the Treatise.

Indeed the whole project of Idealism collapses once we allow the possibility of language, and thence the possibility of successfully referring to objects and states of affairs that are not perceived.

My valued interlocutor is being a bit quick here. Let's sift through this carefully starting with definitions of 'exist(s)' either found in or suggested by a charitable reading of Berkeley's writings.

D1. X exists =_df x is being perceived. (Esse est percipi.)

D2. X exists =_df x is such that, were a perceiver P on the scene, P would perceive x.

D3. X exists =_df either x is being perceived or x is such that, were a perceiver P on the scene, P would perceive x.

(D3) is the disjunction of (D1) and (D2). It is suggested by this passage:

The table I write on, I say, exists, that is, I see and feel it; and if I were out of my study I should say it existed, meaning thereby that if I was in my study I might perceive it, or that some other spirit actually does perceive it. (PHK 3, quoted here) 

God would be the best candidate for 'some other spirit.'  The author of the SEP entry, Lisa Downing, writes,

If the other spirit in question is God, an omnipresent being, then perhaps his perception can be used to guarantee a completely continuous existence to every physical object. In the Three Dialogues, Berkeley very clearly invokes God in this context. Interestingly, whereas in the Principles, as we have seen above, he argued that God must exist in order to cause our ideas of sense, in the Dialogues (212, 214–5) he argues that our ideas must exist in God when not perceived by us.^[20] If our ideas exist in God, then they presumably exist continuously. Indeed, they must exist continuously, since standard Christian doctrine dictates that God is unchanging.

There is much more to it than this, of course, but what I have said suffices to neutralize Ed's objection.  He thinks he has refuted Berkeleyan idealism. He has done no such thing. He ignores (D3).

I must also object to Ed's apparent identification of idealism with Berkeleyan idealism. Ed is being unduly insular. A little to the East of where he lives there is this land mass called The Continent where other forms of idealism have been known to thrive.

I am also puzzled by Ed's talk of phrases like 'my table' needing referents when he himself denies (in his book) that there is extra-linguistic reference and affirms that all reference is intra-linguistic.  As I read him, Ed is a linguistic idealist. Linguistic idealism, however, is by my lights much less credible than Berkeleyan idealism.

Can one see that one is not a brain-in-a-vat?

This is a repost from 21 December 2009, slightly emended. I've added a clarifying addendum.

................................

John Greco, How to Reid Moore:

So how does one know that one is not a brain in a vat, or that one is not deceived by an evil demon? Moore and Reid are for the most part silent on this issue. But a natural extension of their view is that one knows it by perceiving it. In other words, I know that I am not a brain in a vat because I can see that I am not. [. . .] Just as I can perceive that some animal is not a dog, one might think, I can perceive that I am not a brain in a vat. (21)

Really?

A bobcat just walked past my study window. I see that the critter is a bobcat, and seeing that it is a bobcat, I see  that it is not a dog, or a deer or a javelina.  So far, so good. But then John Greco comes along and tells me that in the same sense of 'see' — the ordinary visual-perceptual sense — I can see that I am not a brain-in-a-vat, a BIV. But 'surely' one cannot see or otherwise perceive such a fact. Or so I will argue.

None of us really believe that we are BIVs, and only some really believe that we are creatures of God. Pursuing this parallel may shed some light. So consider:

Q1: How do you know you are not a BIV?
A1: I see that I am not.

Q2: How do you know that you are not a creature of God?
A2: I see that I am not.

These question-answer pairs seem on a par. If the atheist says that he sees that he is not a creature of God, or more generally, sees that the manifest world is not a divine artifact, then we point out to him that this is not the sort of state of affairs that can either be seen to be the case or seen not to be the case. For no matter how intently one observes (whether visually or in any other sense-modality) anything in the natural world, one will not be able to discern whether or not it has creature-status. (By 'creature-status' I mean the ontological status of being a product of divine creative activity.) This is true of the objects of outer perception as well as the objects of (Brentano calls) inner peception, e.g. memories, desires, sensations, etc. And of course nothing is changed by the use of instruments. If I study the moon through a telescope, I will be in no better position to determine that it is a divine artifact than if I view it with the naked eye. Landing on the moon, taking geological selenological samples, won't help either. And the same goes for any instrumental extension of the human senses.

In sum, using 'see' to cover inner and outer sense-perception, whether 'naked' or instrumentally extended, one cannot see whether or not our world is a divine artifact. The same is true with respect to our BIV-status: one cannot see whether or not one is a BIV. For what would one look at, or look for, in order to make this out? Would I stare at the bobcat outside my window and try to isolate a property of the critter that would entail that its appearance to me is solely the result of the machinations of an evil scientist? Or would I look for a property that would entail the animal's not being such a result?

Or is there perhaps some particular thing I must search for the finding or non-finding of which would resolve the question of whether I am a BIV? You may recall Soviet cosmonaut Yuri Gagarin's suborbital flight in April, 1961. He beat the American astronaut Alan Shepard to the punch by a couple of months. What remains with me from the news reports is Gagarin's claim to the effect that he didn't see God out there in outer space.

I thought to myself at the time, "That dumb Commie thinks that God is a physical object floating around in outer space!" Later on it occurred to me that Gagarin might have made his statement just to please the Party ideologues back on the ground in Moscow. Now just as one cannot resolve the God question by poking around in outer space, one cannot resolve the BIV question by poking around in outer sublunary space or inner space.

The atheist who thinks that theism can be refuted by sense-perception is not understanding the issue. The same goes for the theist who thinks that theism can be proven by sense-perception. For the question does not concern observables, but the ontological status of observables. In Heideggerian jargon, it does not concern das Seiende, that-which-is, but das Sein, the Being of that-which-is. In particular, it concerns the ontological status, God-dependent existence.

Similarly, one who thinks that the problem of the external world, which is essentially the problem of the ontological status of the objects of outer perception, can be solved by perception, does not understand the issue. One cannot see that one is or is not a BIV, or dreaming, or being deceived by an evil demon, etc. The question is not about observables, but about their ontological status, their dependence on or independence of our minds or some Mind.

I can see that the animal in front of me is a bobcat. So seeing, I see that the animal is not a dog. But no amount of observation can disclose that the object appearing to me either has or does not have the ontological status of mind-independent existence.

My point is connected with the one I made yesterday, namely, that one cannot refute an idealist such as Berkeley in some quick Moorean way by appealing to some obvious fact of sense-perception.  The good bishop cannot be refuted by kicking a stone.  For Berkeley is not denying that there are stones and such: he is forwarding a theory of their ontological status, and this status cannot be discerned by seeing or touching or experiencing resistance to kicking.

Addendum (3/30/2023)

My adducing of the BIV Gedankenexperiment -- which is usually presented  as an updated Cartesian dream argument -- perhaps unnecessarily complicates the main point I want to make. And this for reasons I won't go into lest I complicate things still further. So consider these parallel questions:

Q3: How do you know that the tree in the quad exists independently of any mind?

A3: Just by looking at it!  It is evident to the senses (and not just the sense of sight) that it exists an sich, in itself, and would so exist even if there were no minds at all whether ectypal or archetypal.

Q4: How do you know that the tree in the quad exists independently of divine creative action?

A4: Just by looking at it!  It is evident to the senses (and not just the sense of sight) that it exists an sich, in itself, and would so exist even if there were no minds as all whether ectypal or archetypal.

Here the parallel is very close indeed. For however we construe divine creation (whether as creatio ex nihilo or as creatio ex deo along Neoplatonic emanationist lines, or even deistically) we absolutely cannot construe divine creation as the production of a material world by a material world-maker. God cannot be a material thing. We are forced to think of him as a mind or spirit who immaterially creates material things, but not out of any pre-existent or pre-given matter.  

If this is intelligible, then Berkeleyan idealism is intelligible. In particular, it is intelligible how a material thing such as the tree in the quad can have an ideal mode of being.  If so, Berkeley is not an eliminativist who denies that there are material beings, but a a sort of metaphysical reductionist who reduces them to ideas in, or rather before, the mind of God.

This is a repost from 21 December 2009, slightly emended. I've added a clarifying addendum.

................................

John Greco, How to Reid Moore:

So how does one know that one is not a brain in a vat, or that one is not deceived by an evil demon? Moore and Reid are for the most part silent on this issue. But a natural extension of their view is that one knows it by perceiving it. In other words, I know that I am not a brain in a vat because I can see that I am not. [. . .] Just as I can perceive that some animal is not a dog, one might think, I can perceive that I am not a brain in a vat. (21)

Really?

A bobcat just walked past my study window. I see that the critter is a bobcat, and seeing that it is a bobcat, I see  that it is not a dog, or a deer or a javelina.  So far, so good. But then John Greco comes along and tells me that in the same sense of 'see' — the ordinary visual-perceptual sense — I can see that I am not a brain-in-a-vat, a BIV. But 'surely' one cannot see or otherwise perceive such a fact. Or so I will argue.

None of us really believe that we are BIVs, and only some really believe that we are creatures of God. Pursuing this parallel may shed some light. So consider:

Q1: How do you know you are not a BIV?
A1: I see that I am not.

Q2: How do you know that you are not a creature of God?
A2: I see that I am not.

These question-answer pairs seem on a par. If the atheist says that he sees that he is not a creature of God, or more generally, sees that the manifest world is not a divine artifact, then we point out to him that this is not the sort of state of affairs that can either be seen to be the case or seen not to be the case. For no matter how intently one observes (whether visually or in any other sense-modality) anything in the natural world, one will not be able to discern whether or not it has creature-status. (By 'creature-status' I mean the ontological status of being a product of divine creative activity.) This is true of the objects of outer perception as well as the objects of (Brentano calls) inner peception, e.g. memories, desires, sensations, etc. And of course nothing is changed by the use of instruments. If I study the moon through a telescope, I will be in no better position to determine that it is a divine artifact than if I view it with the naked eye. Landing on the moon, taking geological selenological samples, won't help either. And the same goes for any instrumental extension of the human senses.

In sum, using 'see' to cover inner and outer sense-perception, whether 'naked' or instrumentally extended, one cannot see whether or not our world is a divine artifact. The same is true with respect to our BIV-status: one cannot see whether or not one is a BIV. For what would one look at, or look for, in order to make this out? Would I stare at the bobcat outside my window and try to isolate a property of the critter that would entail that its appearance to me is solely the result of the machinations of an evil scientist? Or would I look for a property that would entail the animal's not being such a result?

Or is there perhaps some particular thing I must search for the finding or non-finding of which would resolve the question of whether I am a BIV? You may recall Soviet cosmonaut Yuri Gagarin's suborbital flight in April, 1961. He beat the American astronaut Alan Shepard to the punch by a couple of months. What remains with me from the news reports is Gagarin's claim to the effect that he didn't see God out there in outer space.

I thought to myself at the time, "That dumb Commie thinks that God is a physical object floating around in outer space!" Later on it occurred to me that Gagarin might have made his statement just to please the Party ideologues back on the ground in Moscow. Now just as one cannot resolve the God question by poking around in outer space, one cannot resolve the BIV question by poking around in outer sublunary space or inner space.

The atheist who thinks that theism can be refuted by sense-perception is not understanding the issue. The same goes for the theist who thinks that theism can be proven by sense-perception. For the question does not concern observables, but the ontological status of observables. In Heideggerian jargon, it does not concern das Seiende, that-which-is, but das Sein, the Being of that-which-is. In particular, it concerns the ontological status, God-dependent existence.

Similarly, one who thinks that the problem of the external world, which is essentially the problem of the ontological status of the objects of outer perception, can be solved by perception, does not understand the issue. One cannot see that one is or is not a BIV, or dreaming, or being deceived by an evil demon, etc. The question is not about observables, but about their ontological status, their dependence on or independence of our minds or some Mind.

I can see that the animal in front of me is a bobcat. So seeing, I see that the animal is not a dog. But no amount of observation can disclose that the object appearing to me either has or does not have the ontological status of mind-independent existence.

My point is connected with the one I made yesterday, namely, that one cannot refute an idealist such as Berkeley in some quick Moorean way by appealing to some obvious fact of sense-perception.  The good bishop cannot be refuted by kicking a stone.  For Berkeley is not denying that there are stones and such: he is forwarding a theory of their ontological status, and this status cannot be discerned by seeing or touching or experiencing resistance to kicking.

Addendum (3/30/2023)

My adducing of the BIV Gedankenexperiment -- which is usually presented  as an updated Cartesian dream argument -- perhaps unnecessarily complicates the main point I want to make. And this for reasons I won't go into lest I complicate things still further. So consider these parallel questions:

Q3: How do you know that the tree in the quad exists independently of any mind?

A3: Just by looking at it!  It is evident to the senses (and not just the sense of sight) that it exists an sich, in itself, and would so exist even if there were no minds at all whether ectypal or archetypal.

Q4: How do you know that the tree in the quad exists independently of divine creative action?

A4: Just by looking at it!  It is evident to the senses (and not just the sense of sight) that it exists an sich, in itself, and would so exist even if there were no minds as all whether ectypal or archetypal.

Here the parallel is very close indeed. For however we construe divine creation (whether as creatio ex nihilo or as creatio ex deo along Neoplatonic emanationist lines, or even deistically) we absolutely cannot construe divine creation as the production of a material world by a material world-maker. God cannot be a material thing. We are forced to think of him as a mind or spirit who immaterially creates material things, but not out of any pre-existent or pre-given matter.  

If this is intelligible, then Berkeleyan idealism is intelligible. In particular, it is intelligible how a material thing such as the tree in the quad can have an ideal mode of being.  If so, Berkeley is not an eliminativist who denies that there are material beings, but a a sort of metaphysical reductionist who reduces them to ideas in, or rather before, the mind of God.

Argumentum ad Lapidem?

No way, I say.  Over at Substack.

Ed comments:

"He did not maintain that rocks and trees do not exist; he did not deny or even question whether they are; he offered an unusual ontological account of what they are, namely, ideas in minds, including the divine mind." (BV)

True, but careful examination of Berkeley’s argument shows that he provides no clear definition or explanation of what “ideas” are.

He opens the Treatise as follows:

It is evident to any one who takes a survey of the objects of human knowledge, that they are either ideas actually imprinted on the senses; or else such as are perceived by attending to the passions and operations of the mind; or lastly, ideas formed by help of memory and imagination -- either compounding, dividing, or barely representing those originally perceived in the aforesaid ways.

But is it “evident”? I look at the brown and black colours of the surface of my desk. These appear to be qualities of the desk surface itself, and not “imprinted on the senses” at all. Is Berkeley saying that the desk surface itself is imprinted on my senses? But that strange claim has to be clarified. Later on he offers a critique of the idea of substance, arguing that ideas are mental items, therefore cannot be supported by an immaterial item, substance. But that begs the question. If ideas are sensible qualities like colours, what evidence is there for their being mental items?

As for Johnson’s argument, what is the quale corresponding to resistance? Resistance, i.e. Newtonian force, is the most material of qualities. How can there be a quale of resistance without resistance itself?

BV: Newton's First Law of Motion implies that a stone, say, will remain at rest unless acted upon by an external force such as Johnson's kick.  An object at rest thus resists being moved.  This resistance is a (dispositional) property of physical things.  The quale corresponding to this resistance could be called felt resistance.  It is a mental in nature and cannot exist without a perceiver who, for example, tries to move a rock with his foot.

"How can there be a quale of resistance without resistance itself?"  An idealist of the Berkeleyan sort could say that there can't be a quale of resistance without resistance itself but then go on to say that (i) physical things are nothing more than objects of the divine mind, and (ii) resistance qualia exist only in finite (creaturely) minds. In this way the distinction between resistance qualia and resistance itself could be upheld.

The point I was making in my Substack article was that the good bishop cannot be refuted by kicking a stone. This is because Berkeley is not denying that there are stones; he is making a claim about the mode of being of stones, namely that their being/existence is ideal: they are accusatives of divine awareness and nothing more.  As I read him, Berkeley is not an eliminativist about stones and trees in quads, etc.  You could call him an ontological reductionist about such and sundry.

Daniel Dennett, by comparison is an eliminativist about qualia.  He I can refute by kicking 'stones,' namely his cojones. If I kick him in the groin, he will be brought to understand that felt pain, phenomenal pain, lived pain, is the most real thing in the world, and cannot be denied. I am assuming, of course, that he is not a zombie (as philosophers use this term). But that leads us in a different direction.

Berkeleyan and Kantian Idealism: How Do They Differ?

The good bishop, as Kant called him, held that reality is exhausted by "spirits" and their ideas. Thus on Berkeley's scheme everything is either a spiritual substance or mind, whether finite or infinite (God), or else an idea 'in'  a  mind. Ideas are thus modes or  modifications of minds.  As such they do not exist independently of minds. That's what 'in' conveys. If everything is either a mind or an idea in a mind, then bodies are not substances given that a substance is an entity capable of independent existence.  Berkeley's ontology is thus a one (type of) substance ontology. This makes for a contrast with Descartes' dualism of substances, thinking and extended. 

Now the gross facts are not in dispute and no (sane) philosopher is in the business of denying them. So every sane person will agree that there are rocks and trees, tables and turnips. You haven't understood Berkeley if you think that he is an eliminativist about such things. That is why you cannot refute him by kicking a stone.  Anyone who thinks that he can be so refuted is utterly bereft of philosophical aptitude. The question is not whether there are bodies, trees and such; the question is what they are, and what the good bishop is telling us is that they are coherent, cohesive, bundles of ideas. Trees and such exist alright; it's just that their esse est percipi, their being/existence is (identically) their being perceived by some spirit.  

The standard picture assimilates Kant to Berkeley, as I wrote earlier:

P.F. Strawson and H. A. Prichard are exponents of this reading along with many others in the Anglosphere. The standard picture makes of Kant an inconsistent Berkeley who limits knowledge to appearances, these being understood as "mere representations" (blosse Vorstellungen), while at the same time positing an unknowable  realm of things in themselves.  Mere representations are assimilated to Berkeleian ideas so that when Kant states that we know only appearances, what he is telling us is that we know only the contents of our minds.

The standard picture shows a failure to grasp what Kant intends with his transcendental idealism. (Note, however, that whether Kant achieves what he intends is an entirely different question.)  When I taught Kant in the 1980s I used the following three-level schema in order to clarify what Kant means by 'appearance' (Erscheinung) when he is using it in his special transcendentally idealist sense.  There are at least three senses of 'appearance' in Kant. We may call them the manifest, the scientific, and the transcendental. The empirical embraces both the manifest and the scientific and stands opposed to the transcendental. Correspondingly, there are three senses of 'reality,' the manifest, the scientific, and the transcendental.   

Level One: We start with the ordinary 'manifest image' appearance-reality distinction. One day I was hiking Jacob's Crosscut along the base of Superstition Mountain. Off in the brush I espied what appeared to be some big black dogs. In reality, however, they were black bears as a closer look revealed.  This is a familiar sort of case. An initial appearance is shown to be a perceptual mistake, one correctable and in this case corrected by further perception.  The initial, non-veridical appearance was not nothing, but its 'reality' was merely intra-mental, a momentary private datum not amenable to public verification, or even ongoing private verification.  It was a mere seeming or semblance, an instance of what Kant calls Schein and distinguishes from Erscheinung.  Kantian appearances are not private mental data. 

Let 'A1' denote an appearance at Level One, and 'R1' a reality or real thing at Level One. An A1 may or may not be veridical. If I jump back from what I take to be a snake but is in reality a tree root, then the A1 is non-veridical. But when I see a tree root and my partner confirms that what I saw was a tree root, then my A1 and his numerically different A1 are veridical.  So an A1 need not be illusory.  Every A1 purports to be of or about an R1, but the purport does not always 'pan out.'

At A 45 = B63, Kant gives his rainbow example. He tells us that a rainbow may be called a mere appearance and the rain the thing in itself.  This is an example of the Level One appearance-reality distinction. In that same obscure passage,  the careful reader can discern the Level  Three appearance-reality distinction.  For he tells us that the rain drops, together with such primary qualities as shape,  are themselves appearances of a "transcendental object" that "remains unknown to us."  It follows that the rainbow is an appearance of an appearance. The empirical object (rain water refracting sunlight) that is the reality behind the rainbow is itself an appearance of something that does not appear to us as it is in itself.

Level Two.  We now wheel the primary versus secondary quality distinction onto the field. An R1 at Level One has both primary and secondary qualities.  The tree I see when I look out my window has both primary and secondary qualities. To mention just two of its primary qualities, it has a size and a shape. To mention just one of its secondary qualities it is green in color.  At Level Two, R1 is stripped of its secondary qualities, and left with its primary qualities alone. We are now operating within the 'scientific image.'  What was R1 at Level One is now A2 at Level Two.  The real extra-mental tree of Level One is now taken to be an appearance of a deeper reality R2 at Level Two.  Thus:

A1 -------------------> R1 

                                       (R1 = A2) --------------------> R2

                                              

A1 is a representation 'in' the mind of a psychophysical being, a human animal for example. The arrows stand for the representing relation. There is difference between the two relations depicted, but I cannot go into this now. What A1 represents (or presents, stellt vor) is an empirical object R1 endowed with primary and secondary qualities. The secondary qualities are perceived at the object even though, at Level Two, they are understood to be merely relational properties of R2 due to the affection (causal impact) of the thing R2 upon the sensory receptors of the psychophysical subject.  Thus R2 in itself is not colored, etc.  But R2 is in space and possesses a location, a size, a shape, a volume, etc. It is either at rest or in motion which implies the possibility of translation and rotation, etc. which motions bring  objective time into the picture.  

Level Three.  At this level we arrive at the phenomenon or appearance in the specifically Kantian sense. Space and time (and thus all primary qualities) are now stripped from R2 and made out to be a priori forms (or schematizations of such forms), forms that characterize the standpoint of an ectypal intellect, one whose sole mode of intuition (Anschauung) is sensible and thus receptive unlike the intellectual and thus non-sensible mode of intuition of the archetypal intellect whose intuition is creative of its objects.  What exactly this standpoint of the ectypal is is a vexing question. We can say this much with assurance: it is nothing internal to the mind of a psychophysical being such as a human animal, nor is it necessarily dependent on the existence of psychophysical beings.  Extending the above diagram:

 

(R1 = A2) --------------------> R2

                                                    (R2 = A3) -----------------------> R3 (negative noumenon)

(R2 = A3) is an intersubjective object.  It is the objective correlate of the epistemic standpoint of an ectypal intellect.  Nature for Kant is the sum-total of all such phenomena as intersubjective objects. The objectivity of R3, by contrast, is not intersubjective but absolute as befits the objective correlate of the absolute mind of the archetypal intellect, "which all men call God," to adapt a phrase from Aquinas.

The above schema leaves us with a lot of thorny questions.  One such concerns double affection (Erich Adickes). Do both R3 and R2 cause sensations in psychophysical beings?

The main point, however, it is that no one who understands what Kant is trying to do could possibly assimilate his idealism to Berkeley's. There is much more to be said.

Idealism: Subjective, Objective, Transcendental

This from a recent comment thread:

I think we should all agree on what counts as ‘subjective idealism’. I characterise it as the view that the objects we commonly take to be physical objects are in some way, or wholly, mind dependent. This a reasonable interpretation of Kant.

Let's leave the interpretation of Kant for later. The definition on offer raises questions.

1) Does the 'in some way' render the definition vacuous? I see a tree. The tree exists whether or not I am looking at it. But while I am looking at it, the tree has the relational property of being seen by me.  This property depends on my seeing which is a mental act of my mind.  (An act is not an action, but an intentional, or object-directed,  experience.) So there is a way in which the tree is mind-dependent.  It is dependent on me for its being-seen. There is a whole range of such  properties. The tree is such that: it is deemed beautiful by me; falsely believed by me to be a mesquite; thought by me to have been planted too close to the house, thought by you to have been planted just the right distance from the house, etc.  

Or consider money. What makes a piece of paper or a piece of metal money? Obviously, money to be money, i.e., a means of exchange, depends on minded organisms who so treat it.

2) If, on the other hand,  physical things are wholly mind-dependent, then that presumably means that trees and such are dependent on one or more minds for all of their properties, whether essential or accidental, whether monadic or relational, and also dependent on minds for their very existence.  This leads ineluctably to the question as to who these minds are.  Surely the physical universe in all its unspeakable vastness does not depend on my mind or yours or any finite mind or any collection of finite minds.

So the question arises: has there ever been a subjective idealist (as defined above) among the 'name' philosophers?  George Berkeley, you say? But the good bishop brought God into the picture to secure the existence of the tree in the quad when no one was about:

Dear Sir, your astonishment’s odd
I am always about in the Quad
And that’s why the tree
continues to be
since observed by, Yours faithfully, God

If the other spirit in question is God, an omnipresent being, then perhaps his perception can be used to guarantee a completely continuous existence to every physical object. In the Three Dialogues, Berkeley very clearly invokes God in this context. Interestingly, whereas in the Principles, as we have seen above, he argued that God must exist in order to cause our ideas of sense, in the Dialogues (212, 214–5) he argues that our ideas must exist in God when not perceived by us.^[20] If our ideas exist in God, then they presumably exist continuously. Indeed, they must exist continuously, since standard Christian doctrine dictates that God is unchanging. (SEP Berkeley entry)

Now if the ultimate subject of subjective idealism is God, who exists of absolute metaphysical necessity and who creates and ongoing sustains in existence  everything other than himself, then such an idealism is better described as objective. 

Kant's brand of idealism is neither subjective nor objective, but transcendental. What this means I will explain later.