Else said, are there any physical mind-independent objects which are abstractions of other ones?

I’m using mind-independent and mind-dependent like Searle. Things like syntax, language, and computation are mind-dependent and mountains and tables are mind-independent.

Is this why physical reductionism keeps failing, because mind-independent objects can’t be abstracted into one another?

  • Do you believe that 2+3=5 was not true until human minds existed? I take the position that abstract truths, such as mathematical truths, are true regardless of whether anyone is thinking them at a given time, and regardless of whether anyone has ever thought them. To take the position that these truths are always mind-dependent, you would have to assert that 2+3=5 was simply not true 500 million years ago. Do you?
    – causative
    May 19, 2022 at 22:58
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    Are moutains really mind independent, though? Take the twin peaks in Alaska: is it one moutain? Two moutains? A double moutain? I think you might find peoples opinions are divided on this one. The same could go for what is and is not a table. In fact, the more introspection we do about it, the more we find that objects that are truly independent of our mind are few in number.
    – armand
    May 19, 2022 at 23:23
  • @causative I mean I don’t know. I know what different people and theories say and they don’t all agree. But if there are no mind-independent abstractions (maybe someone will provide one), why should humans be so special to be uniquely aware of them? Isn’t that possibly an equal undesirable? If 16 die are a whole different thing than 4, and two particles than one, that world is not using abstraction right?
    – J Kusin
    May 19, 2022 at 23:24
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    Physical reductionism is a further step upon the causal closure principle, thus may encounter more objections from more philosophers. Like Davidson's token identity theory, physical mind-independent objects/events may not determine the relations between mental events which include mind-dependent abstraction... May 19, 2022 at 23:31
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    @DoubleKnot Thanks that seems like a great source for me to learn more
    – J Kusin
    May 19, 2022 at 23:34

1 Answer 1


Abstractions are mind-dependent in the sense that they do not interact with the physical world except through the medium of the mind. Abstract objects have no mass and exert no forces; they are causally inert, yet they can influence physical events thorough the medium of mind. For example, I might go down a line of traffic cones knocking over every third one because I'm superstitious about groups of three. There is a sense in which the number three has influenced the world.

Physical objects are mind-independent in the sense that they interact with the physical world without the medium of the mind. However, there is an important sense in which physical objects are constructed by the mind as Armand suggested in his comment. There are obvious examples such as a place setting consisting of knife, fork, spoon, plate and glass. The only thing that makes this collection of unlike things into a single object is the way that the mind views them. If you follow this sort of logic to its core, you eventually have to conclude that many (and perhaps all) physical objects are essentially just objects because that is how they are perceived. However, despite being, in a sense, mentally constructed, physical object still engage in physical interactions independently of the mind. This is how they are different from abstractions.

So, in answer to your questions: no, there aren't any physical objects that are abstractions because physical objects are mind-independent (in the sense I described) and abstractions are mind-dependent. And, yes, this is one of the many reasons that physical reductionism fails: because abstract objects cannot be reduced to physical objects.


In the comments, @causative notes that a computer program could also do something like knock down every third traffic cone and asks how this is different from a human mind doing it.

My response is that the computer is a physical device that operates on physical causality, so the proper way to evaluate the process is with physical theory. In physical theory, causes are forces, and the number three exerts no forces, so it cannot be a physical cause.

By contrast, my story about knocking over traffic cones was about mental processes. When speaking about mental processes, you use the language of belief, intention, thoughts, etc. It is a different language and requires a different theory of causation. Within this language of mental processes, the number three had an effect.

Now, this dichotomy of language is not by itself controversial. There is no serious thinker who would deny that, in mental language, the cause of me knocking over the traffic cones was my fear of the number three. What is controversial is the connection between my intention to knock over the traffic cone and the physical action of my body to do so. Causative seems to want to deny me the use of mental language on the grounds that I don't have a reduction of that language to the physical, but since no one has a reduction of mental language to physical, that is an unreasonable demand.

Also in the comments, J.D. implies that my use of two different languages means that I am a Cartesian dualist, but one doesn't have to be a dualist to recognize that there are two different languages of causality and that there is no existing reduction of one to the other.


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