Nominalism and realism in metaphysics; universals and particulars.

A universal is a quality or property which can be instantiated in a variety of things or particulars. E.g. the quality of ‘roundness’ or of ‘redness’ are instantiated in a particular, such as an apple or a blushing human cheek. Similarly, the sky and ocean both instantiate the universal - blueness. Plato referred to universals as ideas or forms (you may have heard the phrase - platonic ideas - before).

Now, this gets more complicated when you consider - relations - as universals as well (e.g., north of/south of, before/after, to the left of/to the right of), but we'll leave that alone for now and stick to just adjectives or qualities.

In yet other words - a universal is what particular things have in common, namely characteristics or qualities. Universals are repeatable or recurrent entities that can be instantiated or exemplified by many particular things. Universals can exist in two or more places at once (e.g., the redness of one apple and another apple 1, 000’s of km’s away).

The problem of universals is an ancient problem in metaphysics about whether universals exist. The problem arises from attempts to account for the phenomenon of similarity or attribute agreement among things. For example, grass and Granny Smith apples are similar or agree in property, namely in having the property of ‘greenness’. The issue is: how do we account for or explain this sort of agreement in properties among things?

To answer this, nominalists (and trope theorists) deny the existence of universals and are committed to believing that everything is a particular. To nominalists, abstract ideas of universality only exist in the mind, so that in reality - the redness in this apple is different to the redness that is in another. They are merely particulars, so for nominalists universals are not ‘real’. For nominalists there is no such thing as 'redness' which can be instantiated by different things.

However the trouble with this view is in explaining similarity/resemblance or as philosophers say - qualitative similarity. To many, it is inadequate to deny qualitative similarity or to provide no explanation for it.

Realists, as such, believe that universals like 'redness' and 'squareness' are real and do exist. To realists, universals do not exist in the mind, nor do they exist in space and time. Rather, they have ‘being’ in some eternal and unchanging realm. Most realists also believe that – relations – are universals too. Many famous mathematicians were in fact Realists, including for example Paul Erdős, Kurt Gödel and Bertrand Russell.

Interested in the views of the prominent posters here?

'Ecosystem' is a universe with particulars. Successful non-denial?

Realists are insane.

Like usually, this dichotomy in philosophy is artificial. There is some universality and some particularity between green objects.

This grey scale is "difficult" for philosophy to grasp. Maybe that's why traditional philosophy feels a bit dated.

The next level of philosophy will include cognition deeply inside it. It's surprisingly backward right now - we're still stuck in an 18th century debate where we discuss realness and non-realness rather than including a model of the viewer's cognition as part of the whole package. It's like philosophy still has to discover its own QM weirdness. The Grand Unified Theory of philosophy will be brought together by triple/quad/quintuple indirection, something which human minds are shockingly bad at grasping even at the first level. Perhaps the first AI will find it easier and be able to create these models. Human cognition isn't built to think with more than low level indirection, which is why it takes geniuses to discover new paradigms, even when the new paradigm only required a simple assumption-questioning followed to its logical conclusion.

I think philosophy does well in pointing out the extremes, and that is needed. But it lives of never getting things solved, avoids compromises. Apparently you can't say "both are right" if wanting to make the cut.

Maybe some formula about how right the different views are in different circumstances would be something?

Yeah well said. Philosophy is a mental training and contrasting and perspective-giving tool as much as it something that strives to be correct. Perhaps that's what it needs to be and always will be.

I think philosophy can be detrimental with clever guys digging themselves into trenches. And then saying it's the right way to be.

Do you have an explanation for qualitative similarity?

Nominalists are fond of cognition (/whatever happens in the mind), as an explanation of qualitative similarity. The fact you may not have picked up on this makes me wonder if you've read the OP?

Yes, but it's juvenile and silly. There's zero sophistication or depth in how they deal with cognition. They're still stuck in the language trap - it's like trying to explain physics using words rather than math. You just can't do it except as messy facsimile with little utility.

As for your OP, qualitative similarity is obviously a "real" thing, in the sense that math is real. You can prove this trivially. Anything that has both complexity and structure necessarily has objectively valid abstractions that you can draw out of it.

If math is not real then reason does not exist, for the faculty of reason requires abstraction. And communication and understanding, and words themselves, requires universals as a necessary condition. Thus hardened nominalism is hopelessly self defeating.

To the extent that the nominalists claim generality but not the "reality" of universals, they're just playing dopey word games within the imprecise lanaguage which is unfortunately the standard of philosophy right now. One day, philosophy will be understood in symbols, each with non-word meaning, like physics is described by math. But until that day these debates are just hiding in the giant gaps between words and meanings.

I'm not so bothered by lacking precision. I don't think philosophy ought to be entirely analytic.

The problem of the existence of qualitative similarity is not only a problem of acknowledging whether it exists, but also of - where does it exist? It can't exist only in the mind, and it can't exist in the same sense as something like a rock or a tree exists (in space-time).

I define iPlane as the plane on which abstract ideas exist.

Problem solved.

Non real-ness for things that exist isn't a problem for math. Why should it be for philosophy?

You don't perceive or experience maths in the world, in the same sense that you experience redness for example/qualitative similarity.

The "nomanalist" perspective is that , for example, when one relates to a lion the relationship is through the "word" which is a "tag" onto the individual lion , and no more. the connection between "lions" is more of a grammatical relationship in which the plural is no more than that; an umbrella which comes to the rescue and adds the "s" to the individual lion but in reality it offers no further meaning to the lion species.

The "realist" , of whom is Plato, states that the "idea"' lion is real and contained within the world of "ideas' or "forms". Plato, who was truly aware of mystery wisdom, was able to enter this realm, a realism of activity beyond the senses.

To the nominalist, the thought realm and world of thinking is more of a created process by the self, not entirely known, but none the less a function of the human capability ; as per example to bring forth a"scheme" of activity through their thinking process(if that's what it is for this leads to the question as to the nature of thinking).

The "realist" sees , in some form, that the activity of thinking and thoughts is not manufactured by the human being but is a realm beyond the senses (as we know them) . And ergo, we have the "idea" lion , within the realm of the supersensible which is seen to relate to the entire lion kingdom in creation and vivifying activity. Make no mistake about this, its not an inert picture but a creative realm which works into the individual soul who is actually part and parcel of this same realm.

A perfect example is the botanical work of Goethe. Although there have been others we have Linneaus to thank for the taxometry of the plant kingdom, such as a nominalist approach to species and genus; structured perfectly with the plants assembled in propinquity as to classification.

This is a repeat, its all a repeat; Goethe had a discussion with Schilling , in a garden, and as they admired the flora he explained to Schilling that he appreciated the realm of forms of the plant kingdom. Schiller stated that it was merely an "idea" whereas Goethe explained that if this was only and"idea" then it was enough for him realizing that the words obviously meant different things to the two scientists.

Succiently, Goethe's presentation of the plant kingdom contained the "archetypal" phenomenon in which he could see that the entire plant kingdom was the outer projection of this "archetype" working throughout the world ,both creating the delicate alpine flower and the heavily laden swamp grass .

In the above kingdom of the plants one does not expect the delicate flower in the swamp and one can delineate the differences in flora throughout the world but the telling point is that yes the plant fits the environment but it is more like a man falling into water; the water is not the creative process but the archetype works within what we may call the sense bound material and creates and vivifys the individual plant.

I can only relate to the above in the mater of a "whirling dervish", an ever present dynamic movement, a spinning,you name it, ruining out of words.

One way to approach this presentation is to place two triangles next to each other but not congruent. According to the nominalist they are only individual triangles but not at all connected other than of course adding the (s) to the end of the word.

If one takes a circle and produces multiple triangles and in some manner brings the triangles into motion, different sizes, different angles, and the process continues one can obtain an appreciation of of the"triangle" ala the "realist".

Something not answered above is the question as to whether the nominalist and realist think alike. In truth thinking, which is not owned by the human soul as method or scheme is the same for in human beings is a "sensory activity which is thinking" for when we think we experience a thought which stands alone and so "we experience ourselves united with the stream of cosmic existence".

Its really not that banal for the thoughts of today are stripped of their life and appear as shallow abstractions to the normal soul. In order to appreciate fully "the full thought" we would have to gird ourselves beyond our present abilities for it would be destructive to do it alone. But hey, we are aided by these same supersensible realities who can protect us in this journey; it really speaks to the humility of a Plato or Goethe who comprehended and were able to enter these realms, never alone and forever helpful.

By the way, i am shocked that Bertram Russell would be considered a "realist" for along with Dennett I consider them "poops" of the first order which is a personal joke but good for him. Bertie the brat doesn't need my appreciation; mea culpa, mea culpa.

Thank you for the interesting contribution here Carlo.

And yes, Bertrand Russell argued that the nominalist camp are mistaken, since the majority of them are missing the fact that relations, such as - similarity - are universals as well (e.g., similar to/different to); not only adjectives. The relation - similarity/difference - in particular is key to his argument against the nominalists.

In short, he argues that if the relation - similarity/difference - is a universal, and you're arguing that all particulars are different - you're relying on a universal to make the argument that denies their existence.

Now this idea that relations are universals is quite novel in philosophy, and it has not been looked into very closely yet. Some have used it to hypothesise that a priori knowledge is knowledge that pertains solely to the relations between universals, while empirical knowledge must always include a particular.

I might if I knew what it is.

https://link.springer.com/chapter/10...4471-0509-1_29

Why can't nominalism handle the above?

Because it provides no adequate explanation for qualitative similarity, apart from claiming that the redness of one particular (e.g., the apple in my hand) and another particular (e.g., the apple in your grandma's fruit bowl) are different and that their apparent resemblance is just a product of our mind.
In reality, the redness of the one and the other may be nearly identical, especially when compared against a green apple, for example.
In reality, this qualitative similarity between the two apples would exist regardless of whether we are there to observe it/independently of mind.

I presume you are equating colour with wavelengths of light and such. Physical properties. I don't know how acceptable that is, but maybe distance is a good example to debate.

In reality, A can be closer to B than C is to D. Time taken by light to travel between them, if that's the physical definition (I don't know whether it is). However, some measurements of distance are conventions; miles are more similar to kilometres than cubits are to leagues.

I'm not sure what conclusions that leads to, but do you accept that qualitative similarity can apply to conventions in some cases, at least?

I disagree. There is nothing more fundamental than counting. Do I have one apple or two? The quality of there being "1" or "2" of something is no less real than the quality of something being "red" or "blue"

Qualitative properties are precisely like math. The are repeatable, objectively verifiable observations about structure and relations between structure.

If you do define a "color" dimension, then where something sits on that color dimension is an abstractly measurable quality.

Just like if you define a "y" dimension, then where something sits on that y dimension is an abstractly measurable quality.

There is no difference between those two observations. Both could be equally false or non-existence. Both can be tested by referring to other minds, or by measuring using an apparatus.

Space and the properties of something within 3 dimensions is no more real than color. Yep nominalists have no problem calling spatial observations ("this object occupies this part of space") real. Why? I cannot see a difference between them. They are both minds perceiving and naming a property it's capable of perceiving and naming.

Not sure how relevant this may be...

I was watching this talk by Jordan Peterson on autistic people anyway he used an analogy that when kids draw a picture of a person they draw stick figures representing a person.. this to me is the minds representation of a person IOW (qualitative similarity).

the talk on autism then goes on to say something about autistic's can't abstract, therefore the autistic when asked to draw a person doesn't use the stick representation but has to think of a specific person...

I'm paraphrasing pretty bad here so you may want to just watch the video lol.

Anyway I've grunched this thread pretty good but my intuition is that I agree with the nominalists and that qualitative similarity exists in the mind..

I would say that whether universals exist or not is irrelevant. It's at best underdetermined.

The only thing that really matters is;

'Does assuming universals exist lead to models that are useful in achieving practical or empirical objectives.'

I think the answer is clearly yes. But only because universals fit in so well with the way we think, not the way the universe necessarily works.

I wonder if that's a decent general rule of thumb for determining what paths you should follow and take seriously in philosophy.

'Does assuming <X> exists lead to models that are useful in achieving practical or empirical objectives.'

If <X> is 'God' and our practical objective is get it off with some church crazy girl, then clearly believing in God is something that should be taken seriously.

I read somewhere that most mathematicians are philosophically nominalists about mathematics but think like realists when actually doing the math.


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