How to Recognise Philosophical Nonsense

philosophical nonsense

Philosophy is our ideas about morality, politics, how we find out about the world in which we live, and consequently how we think the world works.

Unfortunately philosophers do not agree on what the basic ideas in these fields are.   They have not agreed on any principles whereby they or we can distinguish good and bad philosophy.

Is there a message in there that will enlighten or educate us? The philosopher is often pushing a world view and gathering what he or she considers evidence to bolster it.

Philosophers, like the rest of us, are susceptible to reaching a consensus that ‘everybody knows’ that turns out later to be false.  Great fashions in thought have lasted for centuries but philosophers abandoned them later.   In recent times there have been claims that philosophy is dead and that science can take the place of philosophy.   Such claims are inherently philosophical in nature.

Books written by professional philosophers are usually difficult to understand.   How come they are so hard?

My book considers the various schools of philosophical and scientific thought and demystifies the arguments in a way that most people can understand.  My view is an empirical one: physics, biology, neuroscience, psychology, psychotherapy and so on. But I recognise that philosophical viewpoints underpin these subjects.

I am not dogmatic that mine is the correct view: other books with titles like “How the Mind works”, “How the Brain makes up its Mind”, “Consciousness Explained” push particular views.   There is not enough evidence yet to make such statements either as conclusions or book titles.   You can make up your own mind.

It is difficult to judge whether a particular philosophical position will prove to be true eventually.   But it is possible with some uncertainty to measure how readable and understandable a text is.

Psychologists have researched what makes texts simple or difficult to read.   The obvious ones are sentence construction and vocabulary.   Simple measures of these factors are sentence length (in words) and the length of the words (in syllables).   A measure which uses these easy to count features of a text is the Flesch-Kincaid Grade Level which is worked out as follows:
grade = 0.39 x average sentence length + 11.8 x average word length – 15.59.

Microsoft Word is happy to calculate this for us (menu: tools/spelling and grammar).
The calculated grade is the US school grade (years of schooling) = six plus the numbers of years in school required to be able to understand the text.

There are a number of similar measures of school grade using slightly different formulae. The web site will calculate these for any supplied text.   The agreement between the various measures is only about ±3, so they can only be taken as a guide.   It is possible to write philosophical nonsense that gives a good readability score!

Here are the measures of readability (average from 5 different measures) for sample texts of approx 1500 words by a few selected philosophers:

This text 11
Plato (428BC-348BC) 11
Richard Dawkins (b1941) 11
My book “Rethinking the Mind” 12
John Searle (b1932) 13
John Locke (1632-1704) 13
Aristotle (384BC-322BC) 14
Benedict Spinoza (1632-1677) 14
Thomas Hobbes (1588-1679) 15
Dan Dennett (b1942) 15
Thomas Reid (1710-1796) 15
Friedrich Hayek (1899-1992) 16
Georg W F Hegel (1770-1831) 16
Immanuel Kant (1724-1804) 17
John Stuart Mill (1806-1873) 17
David Hume (1711-1776) 17
Robert Almeder (b1939) 18
Rene Descartes (1596-1650) 21

The aim of my book has been to make philosophy understandable to people educated to 12th grade.

The first step in reaching a balanced and consistent personal philosophy that one can live by is to approach philosophical texts with sure principles for evaluating them.   I put forward a set of such principles in chapter 1.   You can download it for free by leaving your email address in the green box at the side of this page.

Armed with these principles you can not only understand the arguments that have occurred but by applying these principles evaluate their merits.

You will then be able to see through many of the facile psychological, philosophical and political arguments that are put forward in the media.   The counter arguments have been locked in obscure and impenetrable texts as the above table hints.

Begin your journey to Understanding. Buy the first of the three volumes here:

Common Sense and Reid’s Razor

by Michael Davidson

One of the problems in philosophy is how to set standards by which philosophical theories might be evaluated. Various philosophers have proposed razors, ie philosophical principles that can be used to cut away and discard other philosophical principles and ideas. Perhaps the best known are Ockham’s Razor and Hume’s Fork. Another razor is ‘common sense’. This term has unfortunately become a pejorative in some philosophical and ‘scientific’ circles along with ‘folk psychology’ which means explanations of the behaviour of people in terms of their beliefs and goals, rather than in ‘scientific’ terms such as neurophysiology. One objection to the term ‘common sense’ is that though everyone presumes to have it, it seems to be remarkably absent in others, and it lacks any agreed definition.

Another objection is that our best physics (ie quantum mechanics and relativity) “defies common sense” and since this physics describes how the world is, common sense can and should be discarded as inconsistent with reality. The astrophysicist John Barrow, for example, defines common sense as

“a description that crystallises from what is already known, and implies a certain unwillingness to admit any change, …the implication being that any deviation from it would be uncommonly senseless”.(Barrow 1988)

Similarly the biologist Lewis Wolpert contends

“that ‘natural’ thinking – ordinary day-to-day common sense – will never give an understanding about the nature of science. Scientific ideas are with rare exceptions counter-intuitive: they cannot be acquired by simple inspection of phenomena and are often outside everyday experience. Secondly, doing science requires a conscious awareness of the pitfalls of ‘natural’ thinking. For common sense is prone to error when applied to problems requiring rigorous and quantitative thinking; lay theories are highly unreliable.
. . .I would almost contend that if something fits in with common sense it almost certainly isn’t science. The reason is that the way in which the universe works is not the way in which common sense works.
. . . common sense thinking is quite unsatisfactory [for science]. It is quite different from scientific thinking lacking the necessary rigour consistency and objectivity.
. . . One of the strongest arguments for the distance between common sense and science is that the whole of science is totally irrelevant to most people’s day to day lives.” (Wolpert 1992)

This view seems to promote the alienation of science from the rest of human activity. If science is antithetical to ‘common sense’ it does not follow that because something is contrary to ‘common sense’ it must be true. In another part of the book, Wolpert states that he is ‘a common-sense realist’ ieI believe there is an external world which I share with others and which can be studied.” but holds that his philosophical position is irrelevant to his scientific activities.

In both these examples ‘common sense’ seems to mean the frequent notions that people have about the world particularly in those areas in which they have little or no experience. Appeals to common sense certainly ought to be more careful and more specific about what particular principle is held to be ‘sensible’ and ‘common’. But neither ‘frequent beliefs’ nor ‘common sense’ are a single principle.

The foremost ‘common sense’ philosopher was probably the Scottish philosopher Thomas Reid (1710 – 1796). Reid acknowledged Francis Bacon and John Locke as his predecessors. Reid’s standing as a philosopher diminished at the hands of Kant who was dismissive of common sense as

“but an appeal to the opinion of the multitude, of whose applause the philosopher is ashamed, while the popular charlatan glories and confides in it.” (Kant 1783)

The most well-known ‘common sense philosopher’ of the twentieth century was G E Moore (1873-1958), through his defence of common sense in an essay.(Moore 1925) Karl Popper also claimed that his philosophical theories did not clash with common sense nor with science (Popper 1983). Commitment to ‘common sense’ is of course no guarantee of having it.

Defining what we mean by common sense is not easy. Generally we define it by those things which are not it, for example when someone does something we consider stupid. If we look up the two words in the dictionary we find:

common: shared (as in ‘common property’); open or free to all (as in ‘common land’); frequent (as in ‘a common event’); inferior (as in ‘a common dwelling’).
sense: sensation (as in ‘sense of pain’); understanding (as in ‘it makes sense’); sound reasoning and judgement (as in ‘to speak sense’); opinion or sentiment (as in ‘the sense of the meeting’).

With four possible meanings each of ‘common’ and ‘sense’, (plus some minor meanings) we have plenty of room for misunderstanding and misrepresentation. The form of common sense that is usually dismissed as useless is ‘frequent opinions’ or ‘frequent notions’. Many frequent notions are false and misleading. That is no news. A different reading of the term ‘common sense’ is “the power of reasoning and judgement possessed by people in general and open and free to all.” Very often when this power is brought to bear on frequent notions they are seen to be the falsehoods they are. What is missing from frequent false notions is exactly this power. Obviously I do not mean to say that all mankind are capable of discourse on quantum mechanics; but I do mean to say that most people given the inclination, aptitude and application would be able to appreciate the subject. The sciences are built on this power presumed to exist for all. Not everyone can be an Einstein and trail blaze, but we assume that everyone with an inclination can follow. In the sciences, at least, there are no private lines to God.

‘Common sense’ is for reasons mentioned an unfortunate term. A possible alternative term is ‘good sense’ which perhaps escapes the connotation of “everybody knows (that which turns out not to be so)”, and perhaps sees the term more as an epistemological one than a metaphysical one. It is difficult to see how any principle can stand once we throw out good sense as a starting point.

Reid defined common sense as “that degree of judgement which is common to men with whom we can converse and transact business” (Reid 1785a) I have no quarrel with this definition. To try to avoid the unfortunate connotations of the term ‘common sense’ I refer to this as ‘Reid’s Razor’. Take a philosophical or scientific principle that is being applied to a particular situation: ask yourself whether you would be able to converse rationally and transact business with that person assuming that principle governed the situation or persons involved. If not dismiss the principle as erroneous or at least deeply suspicious. For example, suppose someone proposes that things-as-they-appear-to-be are not things-as-they-really-are. I do not think I would buy a used car from this man.

Thomas Reid (1710 – 1796)
Reid goes on to list a number of principles that he holds to be contingently true (but not necessarily true all the time) (Reid 1785b)

1) Everything of which I am conscious really exists
2) The thoughts of which I am conscious are the thoughts of a being which I call myself, my mind, my person.
3) Events that I clearly remember really did happen.
4) Our personal identity and continued existence extends as far back in time as we remember anything clearly.
5) Those things that we clearly perceive by our senses really exist and really are what we perceive them to be.
6) We have some power over our actions and over the decisions of our will.
7) The natural faculties by which we distinguish truth from error are not deceptive.
8) There is life and thought in our fellow-men with whom we converse.
9) Certain features of the face, tones of voice, and physical gestures indicate certain thoughts and dispositions of mind.
10) A certain respect should be accorded to human testimony in matters of fact, and even to human authority in matters of opinion.
11) For many outcomes that will depend on the will of man, there is a self-evident probability, greater or less according to circumstances.
12) In the phenomena of Nature, what happens will probably be like what has happened in similar circumstances.

According to Reid, anyone who doubts these principles will be incapable of rational discourse and those philosophers who profess to doubt them cannot do so sincerely and consistently. Each of these principles, if denied, can be turned back on the denier. For example, although it is not possible to justify the validity of memory (3) without reference to premises that rest on memory, to dispense with memory as usually unreliable is just not philosophically possible. Reid qualifies some of these principles as not applying in all cases, or as the assumptions that we presume to hold when we converse, which may be contradicted by subsequent experience. For instance with regard to (10) Reid believes that most men are more apt to over-rate testimony and authority than to under-rate them; which suggests to Reid that this principle retains some force even when it could be replaced by reasoning.

I endorse Reid’s principles as normally true and what we must assume to be true to engage in argument and discussion. But, as Reid acknowledges, not all may be true all the time. I thus see Reid’s principles as epistemological rather than metaphysical. Psychologists might point to such things as optical illusions, false memory, attentional blink, hallucinations and various other interesting phenomena which might throw some doubt over some of Reid’s assertions. But these are nonessential modifiers that if entertained as falsifications of these principles would lead to the collapse of all knowledge. Very few philosophers have not acknowledged that the senses can deceive us or that reason is fallible, but to say the senses consistently deceive or that reason is impotent is too big a sacrifice. That the senses can deceive and reason is fallible is good reason to be cautious in our conclusions but not a good reason to dispense with observation and reason all together. Whereas it may be true that

“we are the sort of creatures who cannot help but believe some things that are false,” and “There seems to be no guarantee that our epistemic capacities really give us access to the world,” (Jamieson 1991)

it does not follow that everything we believe is false, nor that our most cherished beliefs – 1 to 12 above – are entirely false.


Barrow J (1988) The World within the World, Oxford University Press, p54
Jamieson D (1991) Method and Moral Theory in Singer P (ed) A Companion to Ethics Blackwell p 476-487
Kant I (1783) Prolegomena to any Future Metaphysics transl J Fieser p6 available at
Moore GE (1925) A Defence of Common Sense in Muirhead JH (ed) Contemporary British Philosophy (2nd series), available at
Popper K (1983) Realism and the Aim of Science Routledge p131
Reid T (1785a) Essays on the Intellectual Powers of Man, Essay 6 Chapter 2 available at (p217)
Reid T (1785b) Essays on the Intellectual Powers of Man, Essay 6 Chapter 5 ibid p240-51
Wolpert L (1992) The Unnatural Nature of Science Faber & Faber pp xi,11,12,16,106,487

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The Logical Leap

by Michael Davidson

Book Review
(first published in Journal of Scientific Exploration 2011 vol 25 no 4)

The Logical Leap: Induction in Physics by David Harriman. New York: New American Library, 2010. 275pp, incl index. $16.00 (paperback) ISBN 978-0-451-23005-8

The so-called problem of induction has been with us since David Hume first drew attention to it in the mid 18th century. The problem is that we infer from a number of similar events laws of nature that are universal. We infer the idea of a cue ‘causing’ a billiard ball to move, by observation of many similar events of cues striking billiard balls. Therefore we suppose that the next time we strike a billiard ball with a cue that the ball will move in a similar way. But, says Hume, there is no valid chain of reasoning that can lead to that conclusion (there is no valid Aristotelian syllogism that leads from ‘some’ to ‘all’). We can introduce an axiom “the future resembles the past” or “nature is uniform in certain regards”, but by so doing we are arguing in a circle:

“all inferences from experience suppose . . . that the future will resemble the past, and that similar powers will be conjoined with similar sensible qualities. If there be any suspicion that the course of nature may change, and that the past may be no rule for the future, all experience becomes useless, and can give rise to no inference or conclusion. It is impossible therefore that any arguments from experience can prove this resemblance of the past to the future; since all these arguments are founded on the supposition of that resemblance” (Hume 1748).

This problem of being unable to get from past observations to some necessarily true
general principle is known as the “problem of induction”.

Induction is contrasted with deduction, which is moving from some true premises inevitably to true conclusions. Aristotle formulated the laws of logic which showed which kind of deductions (syllogisms) lead to correct conclusions, regardless of the actual objects to which the various premises refer. The ubiquitous example is “All A’s are B; C is A; Therefore C is B.” Thus “All men are mortal; Socrates is a Man; Therefore Socrates is mortal.” The point is that the deduction is valid whatever is substituted for A, B and C. The deduction is not necessarily true if the premises are not true: “All men are women; Socrates is a man; Therefore Socrates is a woman”. There is thus a distinction in Aristotelian logic between the validity of an argument and the truth of the conclusion. Aristotle came to his universal laws of logic by a process of induction. First he examined a great many arguments and arranged them into 192 possible forms, removing the particulars to which the arguments referred. Aristotle then isolated 14 valid syllogisms out of the 192 (later expanded to 19 out of 256) which give true conclusions if the premises are true. Although a syllogism may be valid and true it does not necessarily get you very far. Take for example the valid syllogism “no women are immortal; some people are women; therefore some people are mortal.” All the valid syllogisms have “all” or “no” in one or the other of the premises. But the only way such premises can be arrived at is by induction or by definition (as in mathematics).

Yet science proceeds from individual experiments and observations to general principles. It is to the problem of when and why the inference from ‘some’ to ‘all’ is legitimate; “in short, how can man determine which generalizations are true (correspond to reality) and which ones false (contradict reality)”; (p 7) that Harriman sets his mind in “The Logical Leap” subtitled “Induction in Physics”.

To answer the question Harriman relies on the Objectivist philosophy of Ayn Rand (1905-1982, author of the novel “Atlas Shrugged”, where she describes her philosophy in detail, other works of fiction and numerous philosophical essays). This takes for granted the validity of sense perception and causality (p9). Sense perception is our only contact with reality. From sense perception we find out what exists in the world: tables, chairs etc. “We form concepts by grasping similarities that make a group of existents stand out against a background of different existents.” (p10). The concepts formed in this way do not imply that all existents grouped into a concept are the same: their differences are quantitative. For instance, tables have different surface areas, different heights and different numbers of legs. “When we form a concept, our mental process consists in retaining the characteristics but omitting their differing measurements.”(p10)

Concepts are hierarchical. “The meaning of first-level concepts can be made clear simply by pointing to instances.” (p12) For higher level concepts we need definitions which must be empirical statements that specify the distinguishing characteristics and condense our knowledge of them. A concept however cannot be equated with its definition:

“The concept ‘temperature’ had the same meaning for Galileo and Einstein ie both men referred to the same physical property. The difference is only that Einstein knew much more about this property; he understood its relation to heat, to motion, and to the fundamental nature of matter.”(p13)

Generalizations are also hierarchical, and all generalizations ultimately depend on first level generalizations: “all generalizations – first level and higher – are statements of causal connection… there is nothing to make any generalization true except some form of causal relationship.” (p21). Thus, contrary to Hume, we perceive causation directly in the case of the cue and the billiard ball, and in the case of high level generalizations we discover causes by experiment. We do not discover causes by simply counting regularities or finding correlations.

The above is a (condensed) version of Rand’s theory of concepts. The so-called problem of induction relies on prior concepts. “Deduction takes for granted the process of conceptualization. Induction is the conceptualizing process itself in action.” (p35) The process of making higher level concepts requires thought and is therefore not infallible. In fact it is quite difficult.

As an example of correct induction, Harriman cites Benjamin Franklin’s famous experiment with a kite in a thunderstorm which showed that lightening is essentially electricity. Franklin drew on a number of concepts:

“‘electricity’, ‘discharge’, ‘conductor’, ‘insulator’, ‘Leyden jar’. These concepts were made possible by and represent a wealth of earlier knowledge (which was also discovered by means of experiment). Without this conceptual framework, as we may call it, Franklin could only have stared uncomprehendingly at sparks and shocks. Given such a framework, however, he can at once identify what he is seeing: the kite apparatus is a long conductor, and thus the electrically charged thundercloud causes [the Leyden jar to become charged]. Once Franklin can identify what he is seeing in such terms, his conclusion – the generalization – follows directly.”.(p32)

Harriman then discusses at length the progress of scientific knowledge in astronomy, physics and chemistry by the ‘greats’ such as Copernicus, Galileo, Kepler, Newton, Lavoisier, Dalton, Maxwell and Mendeleev and brings out the mechanics of valid induction, though the accounts might be construed as rather Whiggish, wherein the later theory is accepted as correct, the good guys are the ones who got the answer right and the bad guys are the ones who tried to resist the right answer.

From this survey Harriman shows when induction is valid and delineates several fallacies which make induction appear invalid:
a) Dropped context: To say Newton’s laws are falsified by the development of relativity and quantum mechanics is to drop the context. They are true in the context of the mechanics of ordinary bodies and the motion of planets, in which context the laws were validly induced. (p8)
b) Substituting a regularity for a cause: Lavoisier thought that the presence of oxygen in a chemical compound was what made the chemical acidic. This was merely a regularity in those acids he studied and was not found in hydrochloric acid (then known as muriatic acid).(p196)
c) Inadequate experimental controls: Galvani thought that the reason a frog’s leg placed on a silver plate jerks when touched by a bronze hook was because electricity was stored in the leg. Volta thought the reason was contact of the different metals and the frog was irrelevant for the production of electricity. Galvani and Volta both performed variations of the experiment which ‘proved’ their point. Davy later showed that the frog’s leg provided a salt solution vital for the operation of the silver-bronze battery. (p200)
d) ‘Cognitive fixation’: The physicist Lord Kelvin ‘refuted’ the up-and-coming science of geology on the grounds that the age of the Earth, according to the then known physics, was too young for the formation of mountains as postulated by the geologists. Kelvin could not see that the facts of geology suggested another energy source apart from gravity on which he based his calculations. (p206)
e) ‘Cognitive promiscuity’: Pons & Fleischman proclaimed they had been able to obtain the ‘cold fusion’ of deuterium atoms in a room temperature electrolysis experiment, “despite weak evidence and a context that makes the idea implausible… A mind that is open to any ‘possibility’, regardless of its relation to the total context of knowledge, is a mind detached from reality and therefore closed to knowledge.” (p207)
f) ‘Theory stealing’: accepting a theory as an instrument for research whilst not believing that the theory refers to reality. This was the situation through much of the 19th century when many chemists did not believe that atoms actually exist, whilst still using the theory to guide their research. (p220)

In the final chapter, Harriman turns his attention to quantum theory.

“As a mathematical formalism, quantum theory has been enormously successful. It makes quantitative predictions of impressive accuracy for a vast range of phenomena, providing the basis for modern chemistry, condensed matter physics, nuclear physics and optics. It also made possible some of the greatest technological innovations of the twentieth century, including computers and lasers. Yet as a fundamental theory of physics it is strangely empty… It gives a mathematical recipe for predicting the statistical behavior of particles but fails to provide causal models of subatomic processes.” (p248)

According to Harriman, the necessity of supposing that a single reality exists, that the human mind has a reasonably clear access to it, and that the scientist can explain it, has been surrendered not by reference to experimental facts (“the knowledge gained by experimental discovery of facts can never lead to the denial of knowledge and fact.”) but by the influence of post-Kantian philosophy,

“an enemy that operated behind the front lines and provided the corrupt framework used to misinterpret facts. By rejecting causality and accepting the unintelligibility of the atomic world, physicists have reduced themselves to mere calculating machines (at best) – and thus they are unable to ask further questions or to integrate their knowledge.”

Harriman does not discuss the double-slit experiment, the EPR experiments of Alain Aspect and others, the quantum Zeno effect, quantum computation and the various other puzzling phenomena in quantum physics. Harriman himself seems to be ‘theory stealing’ here in that he is willing to accept the benefits he lists from quantum theory without subscribing to the theory itself, nor addressing the really puzzling experimental facts on which the theory is based. There is no explanation of why quantum mechanics gives such precise answers whilst it does not correspond to reality.

I do not deny that modern physics is in something of a crisis. 96% of the universe as we know it consists of ‘dark matter’ and ‘dark energy’ which we have only the vaguest idea about. The two most successful theories we have: quantum mechanics and general relativity refer to completely different contexts and are deeply incompatible in those areas where perhaps they both apply (such as black holes). The effort to unify these two great theories has stimulated physicists to retreat into metaphysical speculation of great mathematical complexity (string theory) with as yet no hint of an experimental test.

In short, Harriman presents a reasonable theory of how a science can proceed by induction to true theories (provided you read ‘true’ as ‘true in context’ and not ‘absolute truth’). He shows, following Rand, that the problem of induction depends on prior concepts that had not been examined by Hume and that science is possible (contrary to the pessimistic conclusions of certain philosophers over the centuries). I am skeptical about his insistence that physics must conform to some pre-ordained form (which might be construed as ‘cognitive fixation’). As Neils Bohr said in response to Einstein’s insistence that “God does not play dice with the universe,”: “Do not tell God what to do.”

“Physics is the most universal of the natural sciences.” (p ix) and Harriman does not address the sciences such as biology, psychology, sociology which suffer from ‘physics envy’ but rely even more on statistics than quantum mechanics. It is here that his theory of induction might meet even tougher challenges.

Hume D (1748) “An Enquiry Concerning Human Understanding” Section IV part II.

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