I don't know what you mean by spiritualism. Spiritualism in philosophy is usually considered to be the belief that there's an immaterial world that cannot be perceived by the senses. It doesn't deny that there's a world that can be (and is) perceived by the senses (and if it did, the fact that we perceive at all would be proof enough).

Are you instead arguing against idealism?

We cannot imagine anything that we have not already experienced in the past. — Samuel Lacrampe

Charles Sanders Peirce offered a similar argument for the reality of his universal categories of Firstness (quality/feeling/possibility), Secondness (reaction/will/actuality), and Thirdness (habit/thought/necessity), as well as his synechism - the doctrine that there is real continuity.

Whatever unanalyzable element sui generis seems to be in nature, although it be not really where it seems to be, yet must really be in nature somewhere, since nothing else could have produced even the false appearance of such an element sui generis. For example, I may be in a dream at this moment, and while I think I am talking and you are trying to listen, I may all the time be snugly tucked up in bed and sound asleep. Yes, that may be; but still the very semblance of my feeling a reaction against my will and against my senses, suffices to prove that there really is, though not in this dream, yet somewhere, a reaction between the inward and outward worlds of my life.

In the same way, the very fact that there seems to be Thirdness in the world, even though it be not where it seems to be, proves that real Thirdness there must somewhere be. If the continuity of our inward and outward sense be not real, still it proves that continuity there really be, for how else should sense have the power of creating it? — Reasoning and the Logic of Things, pp. 161-162

I may have used the wrong term. Nevertheless, I argue against the concept that I have defined, even if the term is the wrong one.

Perception on its own is not a proof for reality. I perceive things in dreams but these perceived things are not real. At least, not in the dream itself.

It took me a couple of tries but I think I finally understand what you wrote haha. Indeed, it sounds similar to my argument. To put it simply, an effect requires an adequate cause; and the existence of spiritual things is not an adequate cause for our perception of physical things.

If it helps you feel any better, it took me about two solid years of reading Peirce - including two complete passes through both volumes of The Essential Peirce and a considerable amount of secondary literature - before I started thinking that I was finally understanding what he wrote. It was totally worth the time and effort, though.

I may have used the wrong term. Nevertheless, I argue against the concept that I have defined, even if the term is the wrong one. — Samuel Lacrampe

I don't know how you define the spiritual (or the physical) so it's kinda hard to comment.

We cannot imagine anything that we have not already experienced in the past. EG: a man that is born blind cannot imagine the concept of a colour. — Samuel Lacrampe

As long as the blind share our background capacities and language there is little that prevents them from understanding descriptions of colours and imagining what colours are like.

It's relatively easy to imagine things or events that violate the laws of nature, such as shining darkness, ghosts, super heroes, and gods. To imagine these things does not require past veridical experiences, they're fictional, not real. We can imagine almost anything. If something is impossible to imagine it might be direct contradictions, such as 'a sun that shines and doesn't shine at the same time', or impossible things such as square circles.

But whence the assumption that the question whether the world is physical or non-physical would somehow depend on our ability to imagine non-physical things? It doesn't.

As long as the blind share our background capacities and language there is little that prevents them from understanding descriptions of colours and imagining what colours are like. — jkop

How would you describe the colour red to a blind man?

I don't know how you define the spiritual (or the physical) so it's kinda hard to comment. — Michael

No problem:
Physical: matter and energy.
Spiritual: all that exists which is not physical. EG: living beings such as angels and souls, but also non-living beings such as logic and morality.

Spiritual: all that exists which is not physical. EG: living beings such as angels and souls, but also non-living beings such as logic and morality. — Samuel Lacrampe

Well, as a possible reductio ad absurdum of your reasoning (unless you accept the conclusion), given that we can imagine such things as angels and souls, it must then follow that such things exist?

As long as the blind share our background capacities and language there is little that prevents them from understanding descriptions of colours and imagining what colours are like. — jkop

I would disagree. The blind can understand the theory behind the colour blue, that is, a certain frequency range of light wave, but he could not "see" the colour blue in his mind.

But whence the assumption that the question whether the world is physical or non-physical would somehow depend on our ability to imagine non-physical things? It doesn't. — jkop

Actually it depends on our ability to imagine physical things. Because if we cannot imagine physical things prior to experiencing them, then how can we explain our perception of physical things if these things don't exist anywhere? If we cannot provide an adequate alternative explanation for that phenomenon, then we must conclude that physical things exist.

The influence of Hume is clear to me.

You seem to be assuming that "physical" is a simple impression, like "blue", but that is doubtful. I have certainly experienced "blue", but how do I know whether I have experienced "physical"?

When we entertain, therefore, any suspicion that a philosophical term is employed without any meaning or idea (as it is but too frequent), we need but enquire, from what impression is that supposed idea derived? And if it be impossible to assign any, this will serve to confirm our suspicion. — Hume

If no impression, then the term is meaningless.

Physical: matter and energy. — Samuel Lacrampe

Do we imagine matter and energy (whatever they are)? Or do we image colours and shapes and sounds and textures and other sensory qualities? The extreme spiritualist could argue that when we imagine things like chairs and tables we're imagining complex arrangements of the latter things, not the former.

Well, as a possible reductio ad absurdum of your reasoning (unless you accept the conclusion), given that we can imagine such things as angels and souls, it must then follow that such things exist? — Michael

I do believe in these things, but I see your general point. The concept of "angels" can be deconstructed into "living beings" and "spiritual", both of which we perceive elsewhere. As for the soul, I think we do not have a clear perception of it. As such, I would not use my argument to prove the existence of these two concepts.

As for the soul, I think we do not have a clear perception of it. As such, I would not use my argument to prove the existence of these two concepts. — Samuel Lacrampe

And that's an opening for the spiritualist. They can argue that we do not have a clear perception (or conception) of the physical (i.e. matter and energy) - see Hempel's dilemma - and so our imaginings are not proof of a physical world.

So at best your reasoning can be used to conclude that chairs and tables and trees exist, but not physical things. In fact, the spiritualist might say that the chairs and tables and trees we imagine are spiritual things.

The extreme spiritualist could argue that when we imagine things like chairs and tables we're imagining complex arrangements of the latter things, not the former. — Michael

I agree with this. But these concepts (colours and shapes and sounds and textures and other sensory qualities) are physical concepts, not spiritual ones. How can the extreme spiritualist explain where these come from, if not from a physical world?

But these concepts (colours and shapes and sounds and textures and other sensory qualities) are physical concepts, not spiritual ones. How can the extreme spiritualist explain where these come from, if not from a physical world? — Samuel Lacrampe

The spiritualist who denies the physical world probably wouldn't deny colours and shapes and sounds and so on. Presumably they still accept that we have experiences? So they'll say that these are spiritual concepts, not physical concepts.

You seem to be assuming that "physical" is a simple impression, like "blue", but that is doubtful. I have certainly experienced "blue", but how do I know whether I have experienced "physical"? — Sapientia

We do not experience "physical", but "blue", which is a physical concept. As long as you have experienced "blue", you need to explain where this experience comes from, if not from a physical world.

Physical: matter and energy. — Samuel Lacrampe

Okay, then "physical" is not a simple impression, but a complex one than can be broken down. But "matter" and "energy" aren't like "blue" or "hot". They aren't simple impressions: clear, lively, vivid sense impressions. They seem more like abstractions which Hume would reject.

So they'll say that these are spiritual concepts, not physical concepts. — Michael

How can that be? Spiritual things such as angels, souls, logic and morality do not possess such things as colours and shapes and sounds and textures and other sensory qualities. Can you find a spiritual thing that does?

How can that be? Spiritual things such as angels, souls, logic and morality do not possess such things as colours and shapes and sounds and textures and other sensory qualities. Can you find a spiritual thing that does? — Samuel Lacrampe

Well, a tree. Your reasoning rests on the premise that when we imagine a tree we're imagining a physical thing. But a spiritualist might reject this premise and say that when we imagine a tree we're imagining a spiritual thing, being that when we imagine a tree we're not imagining these nebulous notions of "matter" and "energy".

We do not experience "physical", but "blue", which is a physical concept. — Samuel Lacrampe

A Humean might think that that word you're using, "physical", is meaningless if it is not itself a sense impression or is not derived from any sense impression. You might as well say that "blue" is a fribbedy concept.

As long as you have experienced "blue", you need to explain where this experience comes from, if not from a physical world. — Samuel Lacrampe

No, I don't. I could be sceptical like Hume. I know that I have experienced "blue", because, for example, I can imagine, say, a blue mountain, which I could not otherwise do. That comes from my impression of "blue".

The only existences, of which we are certain, are perceptions, which immediately present to us by consciousness, command our strongest assent, and are the first foundation of all our conclusions. — Hume

Why go as far as you and assume a physical world? You seem to be assuming scientific realism. You rely upon these scientific terms which you assume are meaningful and descriptive of reality. But that can be subjected to what is arguably reasonable doubt by, for example, adopting a Humean stance. You take some of Hume's thought and try to lead it elsewhere, which is kind of interesting, but I don't think that it's working very well.

Well, a tree. Your reasoning rests on the premise that when we imagine a tree we're imagining a physical thing. But a spiritualist might reject this premise and say that when we imagine a tree we imagine a spiritual thing (or some other non-physical thing). — Michael

Does this mean that, to a spiritualist, a tree (even imaginary) is a spiritual thing, not a physical one? If so, then how does he differentiate between physical and spiritual things?

I would describe the colour indirectly, by referring to its effects on people who can see it, by how they use the word 'red', describe things in which the colour occurs in nature, and its metaphorical uses etc. To imagine what it's like to see red is not to see anything, recall. Imagination is the evocation of an experience via knowledge of one's past or other experiences. Without any past visual experiences the blind can still use knowledge of other experiences, or knowledge of other people's visual experiences, in order to imagine what it's like to see red.

The blind can understand the theory behind the colour blue, that is, a certain frequency range of light wave, but he could not "see" the colour blue in his mind. — Samuel Lacrampe

But when we imagine seeing something we don't really see anything. That's why it is called 'imagination'.

Actually it depends on our ability to imagine physical things. Because if we cannot imagine physical things prior to experiencing them, then how can we explain our perception of physical things if these things don't exist anywhere? If we cannot provide an adequate alternative explanation for that phenomenon, then we must conclude that physical things exist. — Samuel Lacrampe

Are you assuming that the world would be made of your perceptions or imaginations? Why else would you claim that the question whether the world is physical would depend on our ability to perceive physical things?

In a physical world it happens to be possible for certain biological creatures to perceive things, invent a language by which they can talk about their perceived things, as well as other things they don't perceive but imagine. It is even possible to talk complete nonsense. In a non-physical world, however, we wouldn't talk nonsense even, because without the recalcitrance of a physical world inhabited by biological creatures there would hardly be any sufficient reason for the invention and use of words.

But when we imagine seeing something we don't really see anything. That's why it is called 'imagination'. — jkop

I'm guessing he was well aware of that, and that that's why he put scare quotes around the word "see".

Does this mean that, to a spiritualist, a tree (even imaginary) is a spiritual thing, not a physical one? If so, then how does he differentiate between physical and spiritual things? — Samuel Lacrampe

I think the word "spiritual" is bringing a lot of confusion to this conversation. By my reading of this thread, it appears as if you are arguing against the idea that reality is purely mental, or experiential. This position is commonly refereed to as "idealism"' or more broadly speaking 'anti-realism'.

Anyway, in response to the quote above, a "spiritualist"/idealist doesn't believe that anything is physical. To a spiritualist/idealist there would merely be different kinds of tree experiences - eg, trees experienced in waking life (such as when walking through a forest), trees experienced in dreams, trees that one imagines in their minds eye, fictitious trees referred to in books, images of trees, etc. To the idealist, none of these trees are physical, all of these trees exist only as experiences, but they're differentiated from each other by the kind of experiences that they are - they're all experienced in a clearly different way.

What does "seeing" mean when nothing is seen?

What does "seeing" mean when nothing is seen? — jkop

It's a very common metaphor, so I would be very surprised if you were not already aware of its meaning. It's used in that way to mean "to imagine or visualise". To see with your mind's eye. It's not meant to be taken literally, hence the scare quotes.

As long as you have experienced "blue", you need to explain where this experience comes from, if not from a physical world. — Samuel Lacrampe

Why do you not in return though, need to explain where the physical world comes from? The idealist/spiritualist believes reality exists on an experiential level, with no other 'level' of reality causing or holding/bringing the experiential world into existence. You might gawk and demand an explanation for what on earth is causing the experiential world to exist, but the physicalist is merely bringing the 'uncaused' part of reality out from our experiences into a physical world.

At some point, there must be a 'level' of reality that is uncaused, that just exists with nothing causing it or bringing it into existence. You hold that this is the physical level of reality - the physical world doesn't require an explanation/another level of reality which brings it about, causing it to exist. The idealist holds that this uncaused level of reality is our experiences. That there is no level of reality bringing them into existence, the merely exist uncaused.

Do you see my point? Every position has this same feature - that there is a part/level of reality that does not require an explanation for what is causing it to exist. For you, that level is a physical world. For the idealist, that level is our experiences. Both the idealist and physicalist theories have the very same feature - that some part of reality is uncaused and merely exists with nothing holding it in existence - it just exists by brute force and requires no explanation (because it has none), the only difference between the two theories here is the disagreement over which level of reality is uncaused/exists through brute force.

So when you say "you need to explain where this experience comes from", the idealist can simply respond that his experience is uncaused/it exists through 'brute' force - in the very same way that the physicalist would respond to a question about what causes the physical world to exist.

Why must the idealist give an explanation for the cause of his experiences, whereas you don't have to give an explanation for what is causing the physical world to exist? The only difference between your positions here is what level of reality you believe is uncaused and requires no explanation.