A scientific response to the Brain in a Vat

Scientia Salon is an enjoyable webzine discussing philosophical matters, which recently addressed an old conundrum: how do we know we are not a brain in a vat? As I see it, this question is straightforwardly answered by the usual scientific method, so here I’ll summarise the argument that I advanced in the Scientia Salon discussion.

The Matrix-style scenario, which dates back to the skepticism of Descartes, supposes that we are a brain kept alive in a vat, being fed with a stream of inputs generated by an Evil Genius. Everything that we experience as sense data is not real, but is artificially simulated and fed to us. Since, ex hypothesi, our stream of experiences is identical to that in the “real world” explanation, we cannot know for sure whether or not we are such a brain in a vat.

How to respond? First, the whole point of science is to make sense of our “stream of experiences”. We do that by looking for regularities and patterns in those experiences, and we develop those into descriptions and explanations of the world (I’ll use the term “world” here for the sum of those experiences, regardless of whether they derive from our contact with a real world, or from a simulated world being fed to us).

Science attempts to build the best models of that world, meaning the most parsimonious explanations with the greatest explanatory and predictive power. The more parsimonious the description and the greater the predictive power the more likely the model is to be close to the true state of affairs. I’ve previously written a post justifying parsimony, but the main point is that the set of all true statements is vastly smaller than the set of all possible statements, and thus we are only likely to alight on a true statement when guided to it by evidence. Any statement not supported by evidence is most likely to be wrong and thus should be discarded. Thus science’s task is finding the model with the least information content that adequately describes the world.

Now suppose that we are a brain in a vat. Science’s task is still to describe and model everything, including the “stream of experiences”. Regardless of whether the “world” is real or simulated, the standard scientific “real-world model” gives the greatest parsimony and predictive power in describing that world. Any departure from that standard model would result in a worse account (one that is less parsimonious and less predictive about that stream of experiences). That’s because science’s models do work very well about our world and are the best that we have.

One might object that in a “brain in vat” scenario the Evil Genius could feed us any stream of experience he liked, with no rhyme or reason to it, no regularities and no predictability. That is indeed possible, but then the stream of experiences could only be described essentially as a streamed video tape, which is the most information-hungry type of model and one that would be totally useless at predicting anything.

In contrast the “real world” model is very compact in that all one needs are the basic laws of physics and all else follows from that. This model has a vast amount of predictive power, as we know from the fact that engineering works, and planes we build fly, and predictions we make for solar eclipses come true.

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The brain-in-vat model has no capacity to make any predictions at all about the stream of experiences, unless we make all sorts of assumptions about the Evil Genius and why he is feeding us the stream of experiences. Yet, ex hypothesi, we can never have any information about the Evil Genius or his doings.

The only way of regaining any degree of parsimony or predictive power is to build the real-world model into the brain-in-vat model. Thus, we can consider three competing models:

(1) The standard scientific real-world model.

(2) A brain in a vat being fed the {standard scientific real-world model}.

(3) A brain in a vat being fed a video-tape stream of information.

The first of these is by far the most parsimonious. The third is the worst, being vastly less parsimonious than the second. The second is worse than the first since in encompasses everything in the first but then adds a wrapper of additional content. Nor is the additional content trivial, since any explanation would have to describe the Evil Genius and the vat and the brain, and give an explanation of where the Genius came from and why he is acting as he is. This will amount to a whole meta-reality, and since that is going to take a quantity of information akin to that of the standard real-world model, the second scenario is going to involve an information content of order double that of the real-world model.

Thus the brain-in-vat model is invoking that vast increase in information content to explain absolutely nothing at all; it is pointed to by literally no evidence whatsoever, since, ex hypothesi, the brain-in-vat scenario envisages that we have exactly the same stream-of-experiences, and thus evidence, that we have in the real-world model. It is thus a hypothesis bad enough to make William of Occam faint with horror, and can be excised by the merest glance towards his razor.

Indeed, this real-world-plus-meta-reality idea is one of a class of models that all fail for the same reason. We can suppose that all sorts of things could be added to our model of the world (parallel dimensions; Narnia-like realities; orbiting teapots à la Russell; Flying Spaghetti Monsters, et cetera) yet if there is no actual evidence for them then the scientific method simply discounts them.

The in-a-vat wrapper to the real-world model is along the same lines, a vast and needless complication that doesn’t in any way improve the model’s fit to evidence. We could just as well imagine any number of other parallel meta-realities that make no difference to what we experience. Since there are an infinite number of such possibilities the chances of any random one of them being actually true is infinitessimal.

Thus, by the adoption of the usual scientific method, invoking Occam’s razor and principles of parsimony and the need for predictive power, we can reject brain-in-a-vat scenarios. That, of course, does not mean that they can be absolutely ruled out, any more than we can rule out any other hypothesis designed to leave no discernible trace at all on our experience of the world (apophatic theologians are particularly good at inventing these), but the chances of any such suggestion being true is too low to merit taking it seriously.

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Applying falsifiability in science

Falsifiability. as famously espoused by Karl Popper, is accepted as a key aspect of science. When a theory is being developed, however, it can be unclear how the theory might be tested, and theoretical science must be given license to pursue ideas that cannot be tested within our current technological capabilities. String theory is an example of this, though ultimately it cannot be accepted as a physical explanation without experimental support.

Further, experimental science is fallible, and thus we do not immediately reject a theory when contradicted by one experimental result, rather the process involves the interplay between experiment and theory. As Arthur Eddington quipped: “No experiment should be believed until it has been confirmed by theory”.

Sean Carroll recently called for the concept of falsifiability to be “retired”, saying that:

The falsifiability criterion gestures toward something true and important about science, but it is a blunt instrument in a situation that calls for subtlety and precision.

Meanwhile, Leonard Susskind has remarked that:

Throughout my long experience as a scientist I have heard un-falsifiability hurled at so many important ideas that I am inclined to think that no idea can have great merit unless it has drawn this criticism.

Continue reading

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The Religious Freedom Restoration Act establishes religious privilege

In the United States, the Supreme Court tells us, corporations have the status of “people” and thus have attendant constitutional rights including freedom of religion. That allows corporations to decline to participate in aspects of Obamacare if it considers that doing so would be against the corporation’s religious beliefs.

This landmark “Hobby Lobby” ruling followed predictable lines, with five Catholic judges out-voting the Court’s four moderates. Much of the commentary has focused on the doctrine of awarding personhood to corporations. An equally important issue, however, is the role of the 1993 Religious Freedom Restoration Act, whose effects are seen for the first time.

That Act would have been better named the Religious Privilege Establishment Act. It requires that the:

“Government shall not substantially burden a person’s exercise of religion even if the burden results from a rule of general applicability”, with allowed exceptions only where the burden “furthers a compelling governmental interest”, and in addition “is the least restrictive means of furthering that compelling governmental interest”.

This privileges the religious since it grants greater import and status to a religious motivation for doing or not doing something than to a secular motivation for the same thing. Through this promotion of religious belief it is a law “respecting an establishment of religion” and thus it violates the First Amendment. Continue reading

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A “conscience clause” would negate equality under the law

The suggestion of a “conscience clause” opt-out from equality legislation has been floated by no less a person than Lady Hale, Deputy President of Britain’s Supreme Court, and the most senior female judge in the land. The idea is that if treating people equally goes against your conscience then you get to play the “conscience” trump card entitling you to treat people unequally.

Unsurprisingly, some Christians have welcomed the suggestion, which they see as preserving their “religious freedom” against what they see as the encroachment of equality legislation.

“It is obvious that there is a growing conflict between religious freedoms and equalities legislation, and that a new balance has to be struck” opines The Telegraph. So, for example, the Christian hoteliers who famously turned away a same-sex couple, and lost the resulting court case, could in future be indulged by a clause that makes “special provisions or exceptions for particular beliefs”. Continue reading

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A review of “Beyond an Absence of Faith”

This review was written for Richard Dawkins Foundation

Beyond an Absence of Faith, edited by Jonathan Pearce and Tristan Vick, brings us the stories of 16 people who came to reject the faith of their upbringing. Most of the writers are American and former Christians, though some are former Muslims. They tell us of their journeys from strong religious faith to atheism, and in the process give a vivid account of the state of Christianity in America today.

What is striking is how all-encompassing and cult-like religious faith can be. These are not the stories of luke-warm believers, but of people for whom religion was a central feature of their lives. We read stories of people brought up in a “fundie bubble” to the extent that:

At one point, I counted five of seven nights of the week as church functions. Monday was a discipleship with a church leader and some students. Wednesday was a youth service. Thursday was a large-group discipleship, where we met at someone’s house for prayer and Bible study. Friday was the “Powerhouse,” a sort of hangout for teens with live music and a small service. Saturday was the Hellfighters service, and Sunday was the main service …

This is coupled with indoctrination of children so complete that one writer recalls:

I came home to an empty house, and became worried that everyone else had been Raptured away while I was out.

Continue reading

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The multiverse as a scientific concept

This article was first posted in two parts on Scientia Salon.

The multiverse concept is often derided as “unscientific” and an example of physicists indulging in metaphysical speculation of the sort they would usually deplore. For example commenters at Scientia Salon have said that the multiverse is “by definition not verifiable and thus outside the bounds of empirical science”, and that “advocates of multiverses seem to be in need of serious philosophical help”. [1]

Critics thus claim that the multiverse amounts to a leap of faith akin to a religious belief. Indeed, the religious often accuse atheistic scientists of inventing the multiverse purely to rebut the “fine-tuning” argument that they say points to a creator god (though the fine-tuning argument is readily refuted in several other ways, and anyhow physicists really don’t care enough about theology these days to let that worry them; further, the concepts leading to a multiverse were developed well before theologians started taking note of the issue).

The purpose of this article is to argue that the multiverse is an entirely scientific hypothesis, arrived at for good scientific reasons and arising out of testable and tested cosmological models. To be clear, I am not asserting that the multiverse has been proven true, even on the balance of probability, but I am asserting that it is a serious scientific concept that will eventually be accepted or rejected on scientific grounds.

Several different concepts could be labelled a “multiverse”, but I am advocating one particular multiverse concept, that arising from what cosmologists call the “eternal inflation” version of Big Bang cosmology. [2] I’ll outline why cosmologists have arrived at this model, which is now a mainstream account of the origin of our universe, and which leads naturally to a multiverse. Continue reading

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Defending scientism: mathematics is a part of science

While the term “scientism” is often a rebuke to those considered to be overstepping the proper boundaries of science, plenty of scientists will plead guilty to the charge so long as they get a say in how the term is defined. The “scientism” that I defend is the claim that, as far as we can tell, all human knowledge is empirical, deriving from empirical contact with reality. Further, that empirical reality seems, as far as we can tell, to be a unified whole, and thus our knowledge of reality is also unified across different subject areas so that transitions between subjects are seamless.

What we call “science” is the set of methods that we have found, empirically, to be the best for gaining knowledge about the universe, and the same toolkit and the same basic ideas about evidence work in all subject areas. Thus there are no “other ways of knowing”, no demarcation lines across which science cannot tread, no “non-overlapping magisteria”.

A related but different stance is expounded by philosopher Massimo Pigliucci in his critique of scientism [1]. Pigliucci instead prefers the umbrella term “scientia”, which includes “science, philosophy, mathematics and logic”. This sees mathematics and logic as epistemologically distinct from science. Indeed Pigliucci has remarked:

it should be uncontroversial (although it actually isn’t) that the kind of attention to empirical evidence, theory construction, and the relation between the two that characterizes science is “distinctive enough” … to allow us to meaningfully speak of an activity that we call science as sufficiently distinct from … mathematics.

Mathematics is a huge area of knowledge where science has absolutely nothing to say, zip …” [2]

In this piece I argue that mathematics is a part of science. I should clarify that I am taking a broad interpretation of science. Nobody who defends scientism envisages science narrowly, as limited only to what is done in university science departments. Rather, science is conceived broadly as our best attempt to make sense of the empirical evidence we have about the world around us. The “scientific method” is not an axiomatic assumption of science, rather it is itself the product of science, of trying to figure out the world, and is now adopted because it has been found to work. Continue reading

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