After his Delft lecture,¹ Verlinde gave this answer to a question about the possibility of a theory of everything:

I don’t even want to go into the direction of religion or this kind of thing because for me that’s philosophy. What I can do with my equations is only estimate how much information is there, what it’s doing and for us that’s enough. And so I don’t think that that question is part of what we need to answer as physicists. (63:46ff)

It may be guessed that Verlinde has been criticized in the physics community for a tendency to ‘philosophy’. This might especially come from physicists like Lee Smolin who are insistent realists. Here is Smolin in an April 2019 Perimeter Institute lecture, ‘Einstein’s Unfinished Revolution‘:

I don’t want a theory of myself intervening with nature or having a conversation about nature. I’m doing science because I want to understand how nature is in our absence. (…) After all, through most of the history of the universe (…) we weren’t there. So our knowing, believing, thinking, intervening, preparing, measuring shouldn’t play a role in what fundamentally the atoms and the elementary particles are doing.² (…) Those of us are realists believe that nature exists independently of our knowledge and beliefs about it, and that the properties of systems in nature can be characterized and understood independent of our existence and our manipulations. That’s what I mean by a realist. (12:20ff)³

Since information is a primitive property⁴ of the universe for Verlinde,⁵ and since information is necessarily implicated in the “knowing, believing, thinking, intervening, preparing, measuring” rejected by Smolin, Verlinde might seem to violate Smolin’s strictures in the very foundations of his work.  It may well be, then, that his declared aversion to ‘philosophy’ is an apotropaic attempt to deflect such criticism away from his research at the outset. ‘I’m not declaring myself in either of the realist-idealist directions’, he might be seen as assuring Smolin and other realists, ‘I’m just doing my work — please look at my equations before judging what I’m up to.’

Now McLuhan’s undergraduate mentor at the University of Manitoba, Rupert Lodge, held that philosophy comes in three flavors⁶ — realism, pragmatism and idealism.⁷ And Verlinde’s portrayal of his research might be seen as typical of the middle position of Lodge’s three forms, that of the ‘pragmatist’:

Realism interprets experience as a kind of being, idealism as a kind of knowing. It is easy to see that (…) both realism and idealism are one-sided. Experience has been split up into two aspects, and then the whole has been interpreted exclusively in terms of one of its aspects. It is all nature, or all mind. The extreme forms of these views have always invited criticism. (…) Consequently a third type of philosophy has tended to develop: a philosophy which tries to be true to experience, and to avoid all abstract and one-sided theorizings. This attempt at interpretation has taken many forms. One of the best known is called “pragmatism”.⁸

However, despite its declared wish “to avoid all abstract and one-sided theorizings”, such as might seem to characterize only realism and idealism, Lodge saw pragmatism as falling prey to this same ambition (or, at least, the same fate).⁹ He therefore explicitly rejected it as philosophy’s “proper method of study”:

If philosophy is essentially speculative, an affair of alternative possibilities, I must study those alternative possibilities, and must not, in my enthusiasm for realism (or idealism or pragmatism)¹⁰ close my eyes to alternative possibilities. In so far as any one alternative (…) refuses to be regarded as one alternative amongst others, and claims to be in exclusive possession of the whole truth, I must be sceptical of its claims. In fact, in so far as it ceases to be sceptical about its own claims, and becomes [for example] (…) convinced pragmatism, it loses its open-mindedness and is really ceasing to be truly speculative and philosophical.¹¹ ln a word, it is precisely such one-sided philosophizing which is anti-philosophical, and not comparative philosophy, with its scepticism directed against one-sidedness. As the speculative construction of interpretations which essentially admit of alternatives, philosophy is necessarily sceptical of [any and all] one-sided claims; and its proper method of study is necessarily comparative. ¹²

For Lodge, the essential thing was to reject every form of “one-sidedness” and to remain “necessarily comparative”. Such fundamental pluralism in Lodge’s work — and of McLuhan’s in “understanding media” as opposed to ‘understanding the medium’ — is also to be found in Verlinde, notably in his attention to entangement:

• [Qubits] can do something called being entangled in the sense that one qubit, here, is doing the same thing as another one somewhere else [over there]. This is two qubits that are entangled, where the zero of one [qubit] is combined with a zero of the other, or the 1 of the one [qubit] is combined with the 1 of the other. This is an example of entanglement.  So this is the language we’re going to use to consider even our universe — we’re going to think about the universe in terms of information and also in terms of this entangled quantum information. (8:22ff)
• it’s the power of quantum mechanics, it’s the essence of quantum mechanics that we have entanglement. And our [whole] universe [itself] is very entangled. (47.45ff)

The many implications of entanglement are of fundamental importance and will be considered in future posts. Suffice it to note here only that, at a minimum, entanglement entails plurality — and if Lodge and Verlinde are followed, this means essential plurality characterizing the very ontology of everything that exists.¹³ In this case, plurality cannot not characterize philosophy simply insofar as it is part of the furniture of the universe. And if philosophy, too, is essentially plural, it (it!) cannot be waved away as Verlinde does in his answer to the question in Delft (as cited above). Indeed, as Smolin illustrates, even a decided realist can see value to philosophy in at least some of its necessarily plural senses:

Philosophy cannot settle scientific questions, but it has a role to play. A bit of philosophical thought may prevent us from getting hung up on a bad idea, and the record of people who have struggled with the deep questions we face, such as the meaning of time and space, may suggest new hypotheses for us to play with. (The Life of the Cosmos, 1997, 21)

But a stronger claim may be made for philosophy in physics if (a) theory is required to do physics at all¹⁴ and if, as Lodge claimed, (b) philosophy is the comparative investigation of the field of fundamental theories.

As to the first, Eric McLuhan in a lecture claiming his father had no theories, yet somehow managed to cite Stephen Hawking as follows:

“[W]e cannot distinguish what is real about the universe without a theory,” [Hawking] writes. A good, elegant theory will describe a wide array of observations and predict the results of new ones. “Beyond that, it makes no sense,” he points out “to ask if [a theory] corresponds to reality, because we do not know what reality is independent of a theory”.¹⁵

Hawking’s claim that “it is no good appealing to reality”¹⁶ is, of course, not “model independent”¹⁷ itself. So it would appear that, if theory is necessary to do physics at all, and if theory is necessarily plural, something like Lodge’s philosophy as the “speculative construction of interpretations which essentially admit of alternatives” must be applicable within physics before any assurance from it that “it is no good appealing to reality”. Or, of course, before ‘it’ is dismissed out of hand.¹⁸