Realistic Idealism: Twelve Theses.

(Hanna, 2015)

You can also download and read or share a .pdf of the complete text of this essay by scrolling down to the bottom of this post and clicking on the Download tab.

An earlier version of this essay was published in Spanish (Hanna, 2018).

Realistic Idealism: Twelve Theses

I strongly believe that some or another version of metaphysical idealism is true; but I also strongly believe that the true version of metaphysical idealism must be substantively realistic. How can this be so? To show how, I’ll present twelve theses that add up to a realistic idealism. For clarity’s sake, I’ll start by defining some crucial background notions.

By a veridical appearance I mean anything X that appears as F, or appears F-ly, or appears to be F, to any or all rational human cognizers, just insofar as, and precisely because, X really and truly is F. For example, if I say “It appears that someone attempted to assassinate Donald Trump on 13 July 2024,” or “It appears that 2 + 2 = 4,” or “It appears that The Minimal Law of Non-Contradiction—i.e., that not every statement is both true and false (Putnam, 1983; Hanna, 2006)—applies universally,” and what I say is literally correct, i.e., literally the way the manifestly real world is, then all the things I am talking about are veridical appearances.

By the manifestly real world, I mean the world as it veridically appears to any or all rational human cognizers or agents.

By logical possibility, I mean analytic or weak metaphysical possibility; and by real possibility, I mean synthetic or strong metaphysical possibility. Real possibility entails logical possibility, but logical possibility does not entail real possibility. For example, 10,000 year old human animals are really possible and also logically possible; immortal human animals are logically possible but not really possible; and mortal immortal human animals are logically impossible and really impossible. Logical possibility is determined by consistency with the laws of logic, whereas real possibility is determined by consistency with the laws of logic together with consistency with the essential nature of the natural universe, including its basic ontological, mathematical, and physical structure (see, e.g., Hanna, 2024).

By idealism, I mean the metaphysical thesis which says that there are necessary and possibly also essential connections—possibly including identity-relations—between minds and the natural universe.

By subjective idealism, I mean the metaphysical thesis which says that the existence and specific character of the natural universe are necessarily dependent on and strictly determined by any individual rational human agent’s mind, or even only one individual rational human agent’s mind (solipsistic subjective idealism).

And by communitarian idealism, I mean the metaphysical thesis which says that the existence and specific character of the natural universe are necessarily dependent on and strictly determined by some or another community of rational human agents’ minds.

Now for the twelve theses.

Thesis 1: A world that cannot veridically appear, a world “in itself,” a noumenal world, transcending manifestly real spacetime and causal processes, is logically possible but not really possible. (The Real Impossibility of a Noumenal World)

Thesis 2: Necessarily, if the manifestly real world exists, then the specific characters of its basic structures systematically correspond to the specific characters of the innate structures of the rational human cognitive and practical capacities. (World-to-Mind Conformity)

Thesis 3: Necessarily, if the manifestly real world exists, then if rational human agents had been/were differently constituted as to their innate cognitive or practical capacities, the manifestly real world would have been/be correspondingly differently constituted as to its basic structures. (World-to-Mind Covariance)

Thesis 4: Necessarily, if the manifestly real world exists, then if some rational human agents were to exist, they would be able to know or change that manifestly real world to some salient extent, by means of the normal operations of their innate cognitive or practical capacities. (Mind-to-World Access)

Thesis 5: Even if any or all rational human agents were to go out of existence, nevertheless it is really possible for the manifestly real world not only to remain in existence but also to retain all the specific characters of its basic structures. (The Mind-Independence of the Manifestly Real World)

Thesis 6: Necessarily, if the manifestly real world exists, then if some rational human agents were to exist, they would all be able to know or change that world in essentially the same ways, with due allowances made for differences in context. (The Objectivity of the Manifestly Real World)

Thesis 7: Necessarily, if the manifestly real world exists, then for some but not all spacetime locations L in the manifestly real world, if any given rational human agent—call it Bob—were to have been/be actually present, cognizant, and active at L, then the manifestly real world would have been/be differently constituted at L than it would have been/be had Bob not been present, cognizant, and active at L. (The Observer-Dependence of Some Proper Parts of the Manifestly Real World.)

Thesis 8: Necessarily, if the manifestly real world exists, then rational human agents are not only logically (analytically, weakly metaphysically) possible but also really (synthetically, strongly metaphysically) possible. (Anthropocentricity 1)

Thesis 9: Necessarily, if rational human agents had not been really possible, then the manifestly real world would not have existed. (Anthropocentricity 2)

Thesis 10: It cannot be the case that both (i) the manifestly real world exists, and also (ii) rational human agents are really impossible. (Anthropocentricity 3)

Thesis 11: Subjective idealism is false. (Reject subjective idealism)

Thesis 12: Communitarian idealism is false. (Reject communitarian idealism)

If theses 1-12 are all true, then the manifestly real world is non-trivially mind-dependent even though subjective and communitarian idealism are both false—that is, realistic idealism is true. In a nutshell, realistic idealism says that the natural universe is our metaphysical, epistemic, and practical home, and therefore that the natural universe cannot be adequately explained without reference to our real possibility. For a detailed presentation and defense of a version of realistic idealism that I call weak or counterfactual transcendental idealism, see (Hanna, 2015: esp. section 7.3, 2024: esp. chs. 7 and 16).

REFERENCES

(Hanna, 2006). Hanna, R. Rationality and Logic. Cambridge: MIT Press. Also available online in preview HERE.

(Hanna, 2015). Hanna, R. Cognition, Content, and the A Priori: A Study in the Philosophy of Mind and Knowledge . THE RATIONAL HUMAN CONDITION, Vol. 5. Oxford: Oxford Univ. Press. Available online in preview HERE.

(Hanna, 2018). Hanna, R. “Idealismo realista: diez tesis sobre la dependencia mental.” Trans. G. Allende. Reflexiones marginales 58. Available online at URL = <https://2018.reflexionesmarginales.com/idealismo-realista-diez-tesis-sobre-la-dependencia-mental/>

(Hanna, 2024). Hanna, R. Science for Humans: Mind, Life, The Formal-&-Natural Sciences, and A New Concept of Nature. Berlin: Springer Nature. Available in hard-copy and Ebook at URL = <https://link.springer.com/book/10.1007/978-3-031-61113-1>.

(Putnam, 1983). Putnam, H. “There is at Least One A Priori Truth.” In Realism and Reason: Philosophical Papers, Vol. 3. Cambridge: Cambridge Univ. Press. Pp. 98-114.

Download