Paul Austin Murphy: Facebook Philosophy Debates (2)

               Human Beings and Computers

                       Science and Proof

               Communication and Grammar

        The Laws of Physics and Universality

Paul Austin Murphy: Facebook Philosophy Debates (1)

                              Logic and the Constants of Nature

              Hameroff, the Afterlife & Panpsychism

                               Francis Crick and Reductionism

Francis Crick's Deliberately Provocative Reductionism

i) Introduction

ii) Only Dependent on the Brain?

iii) Where in the Brain is an Ambition?

iv) Conclusion

In Francis Crick's 1994 book, The Astonishing Hypothesis: The Scientific Search for the Soul, he wrote the following oft-quoted passage:

“'You', your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules.”

It's easy to believe that Francis Crick was being willfully provocative and rhetorical here. At the same time, he may also have been telling the truth – if only to a degree (as shall hopefully be shown).

In terms of the rhetoric and provocation, it's true that Crick's critical attitude towards religion was one motivation for writing The Astonishing Hypothesis. So, to put it in non-rhetorical terms, Crick certainly did believe that religions can be wrong about scientific issues (as do many religious people). He also claimed that it is science's job to rectify the false claims of these religions. (Or at least those claims which appear to have a scientific subject.)

Crick was also well aware that when he began studying consciousness he was tackling a subject which traditionally had been the sole property of religion and philosophy.

Another point that can be made about Crick's rhetoric and provocation is that he was simply attempting to get a point across. And the best and simplest way of doing that is to be poetic and rhetorical. After all, strongly-expressed views often attract a large audience. Nonetheless, the extremity of a view doesn't automatically mean that it's false  - at least not in every respect. Thus perhaps Crick enticed people in and then gave them a broader and more nuanced perspective on his extreme words (i.e., those quoted above). Though it's of course possible that this is to give Francis Crick the benefit of the doubt.

Despite the opening quote, Crick does express the same idea in a slightly less provocative (i.e., more technical) way. That is, he also wrote:

"A person's mental activities are entirely due to the behavior of nerve cells, glial cells, and the atoms, ions, and molecules that make them up and influence them.”

So is that any better?

As already hinted at, the prefix “seemingly” (as in “seemingly extreme”) is used because what Francis Crick says isn't really extreme at all. It's partly true (if, as stated, in a limited way) – at least in becomes truer when the rhetoric is stripped away and the position is both defended and criticised.

In addition, the very fact that Francis Crick decided to study consciousness in the first place may – or does – suggest that he couldn't have been a reductionist in any strict (or traditional) sense. After all, in much psychology, neuroscience/neurobiology and sometimes even in philosophy, consciousness had been reduced to brain/behavior or simply ignored. Then again, most of The Astonishing Hypothesis is about neurobiology. Thus, even though the opening quotation is in essence a philosophical position, the philosophical defence and implications of that passage are rarely fully developed in the book itself.

Only Dependent on the Brain? 

Let's put the central position in this very simple way.

If it weren't for the brain (or if it weren't for the “nerve cells” mentioned by Francis Crick), then it's indeed the case that we wouldn't have (to use Crick's own words) “memories, ambitions, personal identity, free will, sorrows”. All these things do depend on the brain. Isn't that blatantly obvious to most (though, of course, not all) people?

Now does it follow from this that joys, sorrows, memories, ambitions, personal identity and free will (taken individually) are identical to a group of neurons, a part of the brain, or even the entire brain taken “holistically”? Not really.

Indeed how can one thing actually be another thing? Or in terms of Leibniz's Law:

If x and y are identical, then everything true of x must also be true of y.

Is a group of neurons identical to your memory (to take just one example) of a cat drowning in a river in 2010? In Leibnizian terms again:

i) If your memory of a cat drowning in 2010 is identical to neuron set x (which is its “subvenience base”),

ii) then everything true of that memory (taken as a mental phenomenon) is also true of neuron set x.

Yet surely that can't be the case. 

It is true that the memory (as a mental event/state) itself is about a cat's death in a river. Is neuron set x also about a cat drowning in a river? The memory itself relates to something which occurred in 2010. Does neuron set x also relate to an event in 2010 - at least in the same way as the (mental) memory does? Inversely, brain part x is grey-pink, fleshy and three-dimensional. Is the memory of a dying cat also grey-pink, fleshy and three-dimensional? And so on.

Nonetheless, it's certainly the case that the memory of a cat drowning in 2010 may be “encoded” (let's ignore the precise meaning of that word) in a part of the brain or even (somehow) in much of it. However, is the memory itself simply and purely a part of the brain?

The memory itself has some kind of relation to a past event which was evidently outside the brain. And even if we can say that a part of the brain itself (rather than the the mental content of the memory itself) also has a relation to something outside of it, it still can't be identical to what's outside of it – by definition. 

To repeat: although the memory is indeed dependent on a part of the brain, it can't be identical to it. To paraphrase Leibniz again:

There are things true of the memory of a dying cat that aren't true of the part of the brain which is its material subvenience base. (Let's ignore “externalist” or “broad content” arguments for now.)

One other such truth is the subvenience base of the memory is material – it's made out of neurons, glial cells, atoms, axons, dendrites, molecules, myelin, charged particles, electrical currents, neurotransmitters, etc. Surely the mental memory of a dying cat isn't made out of any of these things.

The Francis Crick quote is problematic in another way too.

Crick seems to be referring exclusively to the brain or to its “nerves cells”. However, joys, sorrows, memories, ambitions, personal identity, etc. also have physiological or bodily aspects which go beyond the brain. Being sorrowful, for example, can make you physically lethargic and even ill. It's true that these physiological or bodily effects are also related to the brain and therefore to Crick's nerve cells. However, like memories, etc., they aren't identical to them. Then again, there are nerve cells (e.g., motor, sensory and autonomic) throughout the body. That is, when you're tired (in the sense that your body becomes weaker, you become sleepy, etc.), even these physiological events/conditions outside the brain are related to neurons in the brain. (Such nerve cells outside the brain are sometimes classed as “projections of neurons”.) Then again, it's still the case that not all nerve cells are neurons.

Where in the Brain is an Ambition?

In the case of certain other examples cited by Francis Crick, it's hard to even conceive of what he means.

Francis Crick mentions “ambitions”. 

More accurately, take the case of a particular ambition of a particular person at a particular point in time.

The idea that a particular ambition is identical to a particular set of nerve cells (or a particular part of the brain) seems very odd. What could it mean?

Let's use Mr X's ambition to want to rule the universe as an example. 

Could that really be fully accounted for by the brain alone (or by a set of neurons)? If it were, then perhaps a neuroscientist could look at that set of neurons and literally either see the ambition or get to knows its content in some other way.

However, let's say that in principle an ambition (or another psychological attitude) is caused/brought about/etc. by a particular part of the brain which can be fully and successfully observed and investigated by magnetic resonance imaging (MRI), elctroencephalography (EEG), or by positron emission tomography (i.e., a “PET scan”). The neuroscientist still wouldn't observe - or get to know the content of - Mr X's ambition to want to rule the world. The only way he could know about the Mr X's ambition would be to ask him.

And even if a precise correlation between this ambition and a part of the brain existed, the neuroscientist would still need to question Mr X about it. 

Conclusion

So Francis Crick may well be confusing the fact that brain parts physically cause, bring about, or physically instantiate (as it were) memories, attitudes, etc. and even that such things can be strongly correlated (at least in principle) with brain parts. However, brain parts (or sets of nerve cells) aren't themselves memories, attitudes, etc. The two things are very different. 

(It's a little like the difference between the cause of a fire and the fire itself. A struck match was a necessary - though not sufficient - cause of a particular forest fire. However, the striking of the match  - or the lit match itself - and the forest fire were very different things.)

Again, the brain's parts are necessary for memories, sorrows, etc; though they aren't identical to - or sufficient for - them. That means that Crick's phrase “are in fact no more” is (strictly speaking) false.

Nonetheless, none of this extra detail (as it were) needs be non-natural, non-physical or “spiritual” in nature. That extra something will include mental states/events, other parts of the body (as well as bodily physiology), the external environment, personal and communal history, language, culture and many other things – all of which are indeed either physical/natural or abstractions from the physical/natural.

Susskind & Steinhardt: The Universal Laws of Physics?

Are the laws of physics universal? That is to ask: Do the laws of physics apply throughout entire universe?

If the laws of physics aren't universal, then wouldn't that have a profound affect not only on physics itself, but also on the pursuit of physics? This is a fairly recent worry for many physicists and cosmologists.

It can now be asked if physicists need their laws to be universal. Yes they do, some may say, in order for there to be laws of physics at all! Others may say that universal laws are required in order to make things simpler (to put it simply). However, can't there be laws of nature which change over time and which don't apply throughout the universe?

The universe itself is... well, universal; though why should the laws of physics also be universal? Of course it can (semantically) be said that the words “law of physics” have the notion of universality built into them. However, isn't that simply a contingent semantic fact (possibly) without any profound or necessary implications?

Despite stating all the above, many definitions of the laws of physics don't even mention their universality.

Take this definition:

“The laws of science, scientific laws, or scientific principles are statements that describe or predict a range of phenomena as they appear in nature.”

And this one:

“Scientific laws summarize and explain a large collection of facts determined by experiment, and are tested based on their ability to predict the results of future experiments.”

Then again, some definitions of the laws of physics do indeed mention their universality. For example:

“Physical laws are Universal. They appear to apply everywhere in the universe....Everything in the universe apparently must comply with them (according to observations).”

In terms specifically of the physical constants (or the “constants of nature”), there's also this definition:

“A physical constant, sometimes fundamental physical constant, is a physical quantity that is generally believed to be both universal in nature and have constant value in time.”

Susskind on Universal Laws

If the laws of physics aren't universal, then what are they?

Let the American physicist Leonard Susskind explain one possibility:

“If these things prove true, then some features of the laws of physics (maybe most) will be local environmental facts rather than written-in-stone laws – laws that could not be otherwise.”

Despite Susskind's words, physical laws were always meant (historically, philosophically and scientifically) to be universal. That is, all the laws of physics were meant to be instantiated in all cases – whether in all similar experiments, similar conditions, when it came to all planets/stars, etc. Thus some people (in response) may say:

How can there be laws at all if they aren't universal?

National political laws, on the other hand, are (to use Susskind's word) “local”. And there are no “genuine laws” in the philosophy of mind or economics either. That's because there are no mental or economic phenomena which are exceptionless. Another way to put that is to say that various “ceteris paribus clauses” are always shoehorned into “mental laws” or the laws of economics in order to make these laws come out as laws. Yet some scientists and philosophers have also said the same about the laws of physics! (See Nancy Cartwright's How the Laws of Physics Lie.)

So if the laws of nature are of ultimate importance in physics (and those laws are supposed to be universal), then anything that fundamentally challenges this will cause a certain amount of consternation within the community of physicists and beyond. (As we'll see with Paul Steinhardt later.) 

Again, if we haven't got laws because we haven't got universality, then what have we got?

Leonard Susskind expresses the worry in this way:

“What... worries may physicists is that the landscape may be so rich that almost anything can be found – any combination of physical constants, particles masses, and so forth. This, they fear, would eliminate the predictive power of physics. Environmental facts are nothing more than environmental facts. They worry that if everything is possible, there will be no way to falsify the theory – or, more to the point, no way to confirm it.”

If Susskind's “landscape” were infinite, then “anything [could] be found”. If we think in terms of the philosopher David Lewis's “possible worlds”, then anything is possible at these worlds - as long as they don't involve logical contradictions, inconsistencies, etc. However, these possible worlds could/do indeed involve different laws of physics and therefore different constants of nature. Thus, as with David Armstrong, we have possible-worlds “combinatorialism” in which not only are properties and facts combined in an indefinite number of ways: so too are the constants of nature.

In terms of Susskind's landscape again: Where does that leave physicists? If laws are “local” or “environmental”, then in what sense are they laws at all? Having said that, is there anything, prima facie, to stop laws from being (merely) local?

Take this hypothetical scenario.

Physicists once knew about a universe which they said was “governed by the same physical laws”. However, it came to be seen that this wasn't actually the case. Instead that universe was really divided in four neat-and-tidy sections.

Now within each of those four sections, the laws were then deemed to be “universal” - or at least they applied (across the board) within each section.

Now what's to stop there being (genuine) laws for each of these four sections of a previously (seemingly) homogeneous large section of spacetime? After all, each section still as its own laws which apply within it.

There is a problem: What's to stop this process continuing?

That is, perhaps each of these four sections (of a once-larger section) were itself be broken up into another four sections (now totaling 16 sections). In principle, this could happen! Indeed this could occur ad infinitum. Though it can also be said that it wouldn't necessarily happen. It just possibly could happen.

So how does this thought experiment compare to what we actually know about our universe in 2019? In terms of any possible sub-spatiotemporal sections of our own known universe, does this scenario so much as make sense?

Susskind: Laws Enable Predictions

Leonard Susskind also ties the laws of nature to what he calls “the predictive power of physics”. In other words, laws are mainly required for reasons of prediction. So if the laws we uphold aren't universal, then wouldn't prediction prove to be more difficult or even impossible? In other words, if laws don't apply across the board, then how are predictions possible?

Perhaps physical laws are still applicable even in our previous hypothetical subsections of the universe. Therefore perhaps such laws may - or will - still do their job in these hypothetical sections.

So what about predictions about the parts of the universe we've never observed? What about those parts we have limited information about? Again, most physicists want both their laws and predictions to be universal. If this weren't the case, then some physicists may say: What's the point? Well, there are lots of sciences which don't deal with universal or exceptionless laws; such as economics, sociology, psychology and the like. However, these disciplines are “soft sciences”. Physics is a “hard science”.

Would the truth of these speculations mean that all the sciences (including physics) are actually soft – at least in relative terms?

Paul Steinhardt: Physical Modality

Let's ask the earlier question again: Are the laws of physics universal?

The Albert Einstein Professor of Science at Princeton University, Paul Steinhardt, asks us a simple question (hinted at earlier) which relates our own questions:

“What is the point of exploring further the randomly chosen physical properties in our tiny corner of the multiverse if most of the multiverse is so different?”

There are wording problems with much of what Paul Steinhardt says above. Nonetheless, that may depend on how literally Steinhardt wants his words to be taken.

For a start, what does the word “randomly” mean in the phrase “randomly chosen physical properties”? If those physical properties weren't randomly chosen, then what would the alternative/s be? That these physical properties are necessary? That God chose them? That God chose them and He did so necessarily?

Why use the word “chosen”? Even if the physical properties weren't random, why did they also need to be chosen? And even if they were chosen, then surely they could still be random in the sense that the Chooser might well have chosen different physical properties. (Or the Chooser might have chosen different laws to underpin these physical properties.)

Again, what do the words “necessary properties” or “necessarily chosen properties” so much as mean?

Are the Laws of Physics Necessary or Contingent?

If someone says

The laws of physics (or nature) are necessary for x.

what is he/she saying? That the laws of physics couldn't have been any other way? Possibly. 

The universe wouldn't be the way it is today (as well as life wouldn't be the way it is today - or even have come about) if the laws of nature hadn't been the way they were at the beginning of the universe and beyond. However, that doesn't make the laws themselves necessary. The necessary relation here is one between the laws of physics and the nature of the universe as it is today.

So what about making a claim about the necessity of the laws being the way they are (or were) in the first place? Why is it necessary for them to be the way they are (or were)? True, if they had been different, then we wouldn't be here today. However, that's not the question. The question is:

Why is it necessary that the laws were/are the way they were/are?

It can be said that it was necessary that they were the way they were in order to bring about the universe we know today. Here again, this is about the (necessary) relation between the laws and the nature of the universe today or indeed at any time. It's not about the laws as they were/are in and of themselves.

All this works for the words “accidental”, “contingency” and “chance” too. Thus:

If the laws of physics are contingent (or accidental), then that only makes sense in the context of the possibility that they might/could have been necessary.

Though if they couldn't have been necessary in the first place, then perhaps they couldn't have been accidental or contingent either.

There is another option which some people make (or simply hint at). 

The physical constants necessarily have their strengths, values, etc. because God made them that way in order to bring about the universe (as well as the people) we know today. (For example, the speed of light, the gravitational constant, the Planck constant, the elementary charge of a proton or electron, etc.)

Though here again that necessity is smuggled in to explain why people are here today and also why the universe is the way it is today. That necessity doesn't (or may not) belong to the laws themselves.

Similarly, when Lawrence Krauss says that

“the laws of physics we observe are mere accidents of our circumstances, and that there could exist an infinite number of different universes with different laws of physics”

what is he actually saying?

More specifically, what function is the word “accident” fulling here? If the laws of physics weren't/aren't accidents (or accidental), then what could they be? Necessary? And if they were/are necessary, then what does that mean? Moreover, if the word “accident” has no purchase here, then neither has the word “necessary”. That's because modal logicians and philosophers often tell us that modal notions only make sense as a package-deal. In this instance, the notion of accident (or contingency) only has purchase alongside necessity; just as possibility (which itself is related to accident/contingency/chance) can only work alongside necessity.

Possible Worlds

If one is a believer in possible worlds (or, alternatively, if one believes that an acceptance of modal notions necessitates a belief in possible worlds), then one won't have a problem with the laws of physics being contingent. This is how John Earman puts it:

“Laws are contingent, i.e., they are not true in all possible worlds.”

Of course we may not need to smuggle in possible worlds in order to question the assumption that laws must either be contingent or necessary. In any case, possible worlds are - by definition (or at least David Lewis's definition) - causally, spatially and temporally cut off from us. So, from a strictly scientific perspective, they're (almost?) irrelevant.

There's also another very simple point. The possibility that physical laws may - or even will - be different at other possible worlds doesn't it stop it from being the case that the laws of physics are universal; just as it doesn't stop them from being contingent or necessary at our world. Then again, if necessity is "what is true at all worlds", and if the laws of our world are necessary, then their necessity must be replicated at all possible worlds.