Cigarettes, Sophistry, and David Hume
Over the past few years, statistical, clinical, and experimental studies of
the relationship between cigarettes and health have resulted in an almost
unvarying succession of bad news to the cigarette smoker. Yet, with
near-equal regularity, the spokesmen (“scientific” or otherwise) for the
tobacco industry have replied with reassurance to the public. These
responses have been both prompt and, by now, familiar in content. “or
example, Mr. Timothy Hartnett of the Tobacco Industry Research Committee
(hereafter the TIRC) has insisted that "nobody has produced evidence
proving that cigarette smoking causes cancer.”1
Hartnett later charged that the 1957 disclosures by the British Medical
Research Council, of the health hazards of smoking "represent opinions about
a theory of cause and effect not confirmed by scientific experiments and
widely challenged in the world of science.”2
In a New Yorker article describing his interviews with leading
executives of the tobacco and advertising industries, Thomas Whiteside
discloses a predictable agreement with the opinions of Mr. Hartnett and
other spokesmen for the Council, John T. Landry of Phillip Morris is
reported to have said “Nobody has ever shown anything conclusive about
cigarettes and health -- lung cancer and all that. It just hasn’t been
More tersely, from Mr. Robert B. Walker, the President of the American
Tobacco Company, we hear that “the hypothesis about smoking (and health) has
not been proved."4
And finally, Mr. Adolph J. Tiogo, the President of the Lennen and Newell
advertising agency reminds us that “there is no proof -- no established
proof -- of cigarettes being harmful."5
What, in fact, is the logical and the practical significance of these
replies. In view of the sobering conclusions of the United States Surgeon
General”s 1964 Report on Smoking and Health, what do these near-automatic
responses by the tobacco companies and advertising offer the cigarette
smoker in the way of reassurance and warrant to continue? Virtually none, it
seems to me.
The sophistry of the TIRC might become more apparent if at first we ask
them, and ourselves, a few basic questions: what is the meaning of a "causal
connection" between smoking and these diseases, both to the research
scientists, or again, to the TIRC? Must a necessary “causal connection"
be proven in order to clearly demonstrate that cigarette smoking is a health
hazard? Just what kind of evidence, if any, would satisfy the TIRC? In
fact, can any scientific theory in principle pass the TIRC”s stiff
standards of "proof"? And most of all, even if it is not “conclusive," how
much weight does all of this evidence bear upon the practical question: Is
cigarette smoking worth the hazard to my life and health?”
I propose to consider these questions, not from the point of view of
science, but from that of Philosophy -- as a student of language, logic and
scientific method. This approach seems particularly appropriate because the
position of the tobacco industry appears to have been sophistical rather
than scientific; seemingly exploiting popular misconceptions about
scientific procedure, causation and evidence, and catering to the
understandable desire of millions of smokers for easy reassurance.
The burden of the TIRC case seems to rest upon a challenge to the
scientists to demonstrate "conclusively" (i.e. to "prove") a necessary
"causal connection" between cigarette smoking and lung cancer and other
diseases. The argument of the eighteenth century philosophy, David Hume,
essentially accepted by most philosophers of science and working scientists,
would seem to invalidate this challenge. From a carefully reasoned argument,
Hume concluded that our conception of causation is derived from our
experience of "conjoined phenomena" and not through our direct perception of
necessary “causal connections.” Following Hume’s example; while we notice
the wax melt as we heat it, we do not perceive the “cause” as such. We see
merely the event of the heating followed by the event of the melting wax. As
this experience is repeated, we then come to conclude that the heat causes
the melting. Indeed, the invariable correlation of these events comes to
mean the "cause.” Says Hume:
When we look about us towards external
objects, and consider the operation of causes, we are never able, in a
single instance, to discover any power or necessary connexion; any
quality, which binds the effect to the cause, and. renders the one an
infallible consequence of the other. We only find, that the one does
actually, in fact, follow the other. . . . There is not, in any single,
particular instance of cause and effect, any thing which can suggest the
idea of power or necessary connexion."6
From our repeated experience of
"conjoined” events, and our statistical and experimental studies thereof, we
presume a “connection” to exist. Such is the basis of a scientific
demonstration of causation as most scientists and philosophers of science
will agree. And thus, this necessarily is the basis of the studies which
have indicated a health hazard in smoking.
But perhaps the industry does not ask for a demonstration of a "necessary
connection in Hume's sense; rather they ask for a thoroughgoing "scientific"
account of the alleged biochemical changes in the cell that result from an
exposure to certain components of cigarette smoke. If so, then we must
apparently concede that this “clear connection" is not known, however
important such knowledge might be to medical science. Nonetheless, this
mystery does not invalidate the clear statistical evidence that cigarette
smoking does increase the chances of contracting lung cancer or certain
Consider an analogous case; Almost any child knows, by direct experience,
that if his hand touches a very hot object, his hand will be burned. He
knows this, although he has not touched every possible hot object. Yet only
the physiologist begins to understand the complex
physical-.chemical-neurological phenomena that attend this event, and in
fact much mystery remains in this matter. However, this medical mystery in
no way encourages the child to touch another hot stove. So too we may know
very well that cigarette smoking is a cause of lung cancer without fully
knowing how this happens. But the analogy is incomplete; unlike cigarette
smoking, no pleasure and no social approbation attends a burned hand.
Moreover, no multi-billion dollar industry depends upon a public compulsion
to be burned, nor are millions of dollars spent on advertising messages to
daily persuade us to partake of that particular act of masochism.
So much for the demand to exhibit the "necessary connection." Let us now
examine the next challenge of the industry: "Are the results of these
studies conclusive?" For practical purposes they apparently are. In an
absolute sense, they are not, no can they be for these studies are the
results of empirical research. But by the same token, the law of gravitation
is not "conclusive” for all falling objects have not been examined, nor can
we be absolutely assured that falling objects will behave in the future as
they have in the past. As Hume observed: The bread, which I formerly ate,
nourished me; . . . but does. it follow, that other bread must also nourish
me at another time. . . ? The consequence seems no wise necessary."7
Yet we refrain from jumping out of windows, albeit the law of gravitation is
not "absolutely" certain. We retire at night confident of the "unproven"
assumption that the sun will rise as usual in the morning.
We can carry this point every further: the Surgeon General’s conclusions are
fallible, as in a sense they must be if they are to be at all meaningful.
"Fallible," but not "false." By this I mean that a meaningful hypothesis
must not only affirm, but it must deny as well. It cannot simply be true for
every conceivably possible world, but must be shown to be conceivably false
though actually true for the world of facts as encountered by the scientist.
And so the Report must allow us to conceive of experiments that would render
its findings false -- and it must be demonstrated that such conceivable
refutations have not been borne out by investigation. Any casual reader of
the report will discover that it meets this test of fallibility admirably.
Of course, the list of possible refuting experiments can be extended
forever. And though we employ several million scientists to study the
effects of smoking for several generations, we cannot in principle deny the
conceivability that the next study will refute the hypothesis. -- we must
not deny it, if the hypothesis is to have meaning. In this sense, then, the
cigarette-cancer theory is "inconclusive.
In this sense, Harvey's theory of the circulation of the blood, and
Pasteur's germ theory of disease are also “inconclusive." But of course, in
the work of science the point is commonly reached at which a theory is
accepted as true beyond reasonable doubt.” The question of “fallibility"
then becomes just another logical problem to the philosopher of science --
and another red herring for the sophist.
In response to such sophistry, one need only ask: “Just what sort of
evidence would convince you of a “necessary connection" between cigarette
smoking and lung cancer?" "What sort of demonstration would you accept as
“conclusive”?" There seems to be little evidence that the TIRC is
prepared to answer such questions in a manner that will not expose their
sophistry. If, then, they are unprepared at the outset to accept any
conceivable "proof," what business have they in posing these challenges?
If it is to be granted that the evidence against smoking must, in principle,
be logically “inconclusive," what practical difference does this make in
view of the enormous statistical evidence from countless studies, of a
concomitance of smoking to lung cancer and other chronic diseases? The
theoretical difference between high probability and certainty should make
virtually no practical difference. Only a few years ago, a boy survived a
plunge over Niagara Falls. Thus we have clear evidence that such a mishap
does not bring certain death. The hypothesis: ”If I am swept over Niagara
Falls, I will be killed," is not “conclusive." Yet no sane person who values
his life will casually swim in the Niagara River rapids above the Falls. Not
even a sophist will carelessly expose himself to probable -- but not certain
-- loss of life, simply because he has a "chance" of survival -- not if the
danger is clear and present. The alternative to a “conclusive proof” of risk
may be an “overwhelming probability:" A prudent person will respond to such
a high probability of danger as if it were a certainty. This seems a clear
point of immediate personal concern to every cigarette smoker. One may not
expect to hear it raised by the TIRC
In summary, medical science is necessarily (though not entirely) inductive.
From a controlled study of samples, the scientist arrives at conclusions
concerning all cases. When his predictions are verified unerringly and rival
hypotheses are refuted, we then have substantial scientific knowledge. This
approach has supplied knowledge which is firm enough to warn us of many of
the present hazards to our health. To ask any specific scientific inquiry to
meet additional and impossible criteria of proof -- criteria that are
ill-defined at that -- is to engage in clear and simple sophistry.
The fundamental standards of sound inquiry were well stated by Hume:
If we take in our hand any volume . . .
let us ask, does it contain any abstract reasoning concerning quantity or
number? No. Does it contain any experimental reasoning concerning matter of
fact and existence? No.. Commit it then to the flames; for it can contain
nothing but sophistry and illusion.8
On both counts, the Surgeon General's
Report should not only be spared from the flames, but should be seriously
considered by all cigarette smokers.
The TIRC argument that no "necessary connection” Has been found is,
strictly speaking, correct. It is also trivial and irrelevant. The same
argument would invalidate any empirical scientific law. Nonetheless, upon
this astonishing conception of scientific method, they have established
their strategy: (1) Take a seemingly reasonable request for "conclusive"
evidence -- a request which, in fact, is vague and which is in logical and
scientific principle, impossible to answer. That is to say, present a
challenge which need never be -- in fact can never be fully met. (2)
Broadcast the necessary ”failure" after each new item of evidence against
smoking is released, thus suggesting that the whole enterprise is
inconclusive and unproductive. A smoking public, eager for justification)
and an industry eager to preserve its profits, will be over grateful.
As, to be sure, they have been.
University of Utah.
PS (2012): See also my
"Is Science Just Another
NOTES AND REFERENCES
1. The Consumers Union Report on
Smoking and the Public Interest, Mount Vernon, New York, Consumers
Union, 1963, p. 109. (My italics)
2. The Consumers Union Report on Smoking and the Public
Interest, Mount Vernon, New York, Consumers Union, 1963, p. 109. (My
3. Thomas Whiteside, "A Cloud of Smoke “ The New Yorker,
November 30, 1963, p. 96.
4. Thomas Whiteside, “A Cloud of Smoke,” The New Yorker,
November 30, 1963, p.105-6.
5. Thomas Whiteside, “A Cloud of Smoke,” The New Yorker,
November 30, 1963, p.108.
6. David Hume, An Enquiry Concerning the Human
Understanding, Chapter VII, Part I.
7. Hume, Enquiry... , Chapter IV, Part 2.
8. Hume, Enquiry... Chapter XII, 3.