Knowledge, Belief, and Evidence

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Knowledge, Belief, and Evidence

• Chapter 5

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Knowledge, Belief, and Evidence

• Knowledge is power, according to Francis Bacon.
• Since knowledge is needed to help us attain our
  goals and to make sense of the world, then we
  must be clear about what knowledge is and how to
  acquire it.

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Babylonian Knowledge-Acquisition Techniques

• Hepatoscopy- divination through inspection of the
  liver.
• In Mesopotamia, hepatoscopy was considered to be
  such an effective knowledge-acquisition technique
  that only kings and nobles were allowed to use
  it.
• While hepatoscopy is no longer big business, that
  other form of divination pioneered by the
  Babyloniansastrologystill is.
• There are over ten thousand professional
  astrologers in the U.S. alone.

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Knowledge, Belief, and Evidence

• Astrology claims a causal relationship between
  the prophetic sign (the stars and planets) and
  the events to which they correspond that
  hepatoscopy doesnt.
• In hepatoscopy, the liver isnt the cause of the
  events it foretells, it is merely a record of
  them.
• In astrology, on the other hand, the stars and
  the planets supposedly help to bring about the
  events they portend.

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Propositional Knowledge

• A fact, in the sense we are using it here, is a
  true proposition.
• Thus, factual knowledge is often referred to as
  propositional knowledge.
• One of the first and foremost attempts to
  characterize propositional knowledge can be found
  in the works of Plato.

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Propositional Knowledge

• The point that Plato is trying to make here is
  that while having right opinions (true beliefs)
  may be a necessary condition for knowledge, it is
  not sufficient there must be something more to
  having knowledge than just having true beliefs.
• True belief is necessary for knowledge because we
  cant know something thats false, and if we know
  something, we cant believe that its false.
• We CAN believe something that is false but not
  KNOW something that is false.

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Propositional Knowledge

• For example, we cant know that 22 equals 5
  because 22 does not equal 5. In other words, we
  cant know what isnt so.
• Similarly, if we know that 22 equals 4, we cant
  believe that it doesnt.
• To know that something is true is to believe that
  its true.
• True belief is not sufficient for knowledge
  because we can have true belief and yet not have
  knowledge.

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Propositional Knowledge

• True opinions, Socrates tells Meno, are a fine
  thing and do all sorts of good so long as they
  stay in their place, but they will not stay long.
  They run away from a mans mind so they are not
  worth much until you tether them by working out
  the reasonOnce they are tied down, they become
  knowledge.
• For Plato, then, knowledge is true belief that is
  grounded in reality, i.e., has justification.
  What grounds our beliefs in reality are the
  reasons we have for them.

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Reasons and Evidence

• Reasons confer probability on propositions. The
  better the reasons, the more likely it is that
  the proposition they support is true.
• Does knowledge require certainty then? To know a
  proposition, must we have reasons that establish
  it beyond a shadow of a doubt?
• If knowledge requires certainty, however, there
  is little that we know, for there are precious
  few propositions that are absolutely indubitable.
  You might object that there are many things you
  know for certain, such as that you are reading a
  book right now. But do you? Isnt it possible
  that you are dreaming at this moment?

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Reasons and Evidence

• The view that we cant know what isnt certain is
  often espoused by philosophical skeptics.
  According to these thinkers, most of us are
  deluded about the actual extent of our knowledge.
• So if knowledge doesnt require certainty, how
  much evidence does it require? It does not need
  enough to put the claim beyond any possibility of
  doubt but, rather, enough to put the issue beyond
  any reasonable doubt.

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Reasons and Evidence

• A proposition is beyond a reasonable doubt when
  it provides the best explanation of something.
• We are justified in convicting someone if we have
  established his or her guilt beyond a reasonable
  doubt. Similarly, we are justified in believing
  a proposition if we have established its truth
  beyond a reasonable doubt. But being justified
  in believing a proposition no more guarantees its
  truth than being justified in convicting someone
  guarantees his or her guilt.

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Reasons and Evidence

• Nevertheless, if we are justified in believing a
  proposition, we are justified in claiming that it
  is true indeed, we are justified in claiming
  that we know it. Such a claim could be mistaken,
  but it would not be improper, for our
  justification gives us the right to make such a
  claim.
• If we have good reason for believing a
  proposition to be false, we are not justified in
  believing it to be true, even if all or our
  sensory evidence indicate that it is.
• There is good reason to doubt a proposition if it
  conflicts with other propositions we have good
  reason to believe.

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Propositional Knowledge

• The structure of our belief system can be
  compared to that of a tree. Just as certain
  branches support other branches, so certain
  beliefs support other beliefs.
• And just as bigger branches support more beliefs
  than ancillary ones.
• Accepting some dubious claims is equivalent to
  cutting of a twig, for it requires giving up only
  peripheral beliefs.
• Accepting others, however, is equivalent to
  cutting off a limb or part of the trunk, it
  requires giving up our most central beliefs.

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Reasons and Evidence

• The search for knowledge, then, involves
  eliminating inconsistencies among our beliefs.
• The more background information a proposition
  conflicts with, the more reason there is to doubt
  it.
• When there is good reason to doubt a proposition,
  we should proportion our belief to the evidence
  (Humes Maxim restated)
• The more evidence we have for a proposition, the
  more credence we should give it (and vice versa).
• Bertrand Russell stated, It is undesirable to
  believe a proposition when there is no ground
  what ever for supposing it true.

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Appealing to Authority

• If you say you believe something
• Because you read it in a book
• Because a teacher, parent, mentor, hero or
  minister said it
• You are engaging in appealing to authority as
  justification.
• In psychology, call it modeling why many people
  have particular religious and political
  affiliations.
• Intermittent verification (i.e., reinforcement
  via confirmation) can make any belief much more
  persistent

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Expert Opinion

• (1) That when the experts are agreed, the
  opposite opinion cannot be held to be certain,
  (2) That when they are not agreed, no opinion can
  be regarded as certain by a non-expert and (3)
  that when they all hold that no sufficient
  grounds for a positive opinion exist, the
  ordinary man would do well to suspend his
  judgment.

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Expert Opinion

• There often appears to be an inverse correlation
  between degree of conviction and evidence the
  less evidence there is for a proposition, the
  more fervently it is believed.
• To avoid holding unjustified beliefs, then, its
  important to develop a healthy commonsense
  skepticism. Unlike philosophical skepticism,
  commonsense skepticism does not consider
  everything that lacks certainty suspect. Rather,
  it considers everything that lacks adequate
  evidence suspect. Commonsense skeptics wont
  believe something unless they have good reason
  for believing it, and their belief will be
  proportionate to the evidence.

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Degrees of Skepticism

• A person can have such absolute skepticism that
  they are skeptical of their skepticism, doubting
  everything.
• A close second would be philosophical skepticism
• A person can so absolutely lack skepticism that
  they will believe virtually anything.
• A reasonable or justifiable degree of skepticism
  could be common sense (open minded) skepticism)
  being willing to believe something to the extent
  that it has adequate evidence.

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Expert Opinion

• There is good reason to doubt a proposition if it
  conflicts with expert opinion.
• But the opinion of experts is superior to our own
  only in their fields of expertise. Outside their
  specialties, what experts say carries no more
  weight than what anyone else says.
  Unfortunately, people have a tendency to treat
  the opinions of experts as authoritative even
  when theyre speaking out of their depth.
• Conferring a Ph.D. on a person seems to give
  that person the inability to say I am wrong or
  I must be mistaken. (James Randi).

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Expert Opinion

• Just because someone is an expert in one field
  doesnt mean that he or she is an expert in
  another.
• To cite a nonexpert as an expert is to make a
  fallacious appeal to authority. Its fallacious
  because it doesnt provide the type of evidence
  it purports to. Instead, it attempts to deceive
  us about the quality of the evidence presented.
  To avoid being taken in by this kind of
  subterfuge, we need to know what makes someone an
  expert.

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Expert Opinion

• The designation expert is something you earn by
  showing that your judgments are reliable. To be
  considered an expert, you must have demonstrated
  an ability to correctly interpret data and arrive
  at conclusions that are justified by the
  evidence. In other words, you must have shown
  yourself capable of distinguishing truth from
  falsehood in a particular field.
• Expert testimony, like any testimony, is credible
  only to the extent that it is unbiased, (i.e.,
  objective).
• The current problem with the FDA
• Can a polygraph be detecting lying even with a
  plant as a subject? Is lying really being
  detected?

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The Demise of the Congressional Office of
Technological Assessment

• For decades, the US Congress relied on a panel of
  independent scientists to give advice on funding
  for research projects, the OTA. Members of the
  OTA were independent of any funding dependent
  upon government funding.
• The OTA was dismantled in 1994 because the House
  leadership argued (a) there was always a
  differing (but usually a minority) opinion to be
  found, (b) the OTA was argued to merely be a
  liberal information source because of (a).

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Coherence and Justification

• Coherence alone is not enough for justification
  because a coherent set of propositions may not be
  grounded in reality.
• Since justification is supposed to be a reliable
  guide to the truth, and since truth is grounded
  in reality, there must be more to justification
  than mere coherence.

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Sources of Knowledge

• The traditional sources of knowledge
  perception, introspection, memory, and reason
  are not infallible guides to the truth, for our
  interpretation of them can be negatively affected
  by all sorts of conditions, many beyond our
  control.
• If we have no reason to doubt whats disclosed to
  us through perception, introspection, memory, or
  reason, then were justified in believing it.

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The Appeal to Faith

• To believe something on faith is to believe it in
  spite of, or even because of, the fact that we
  have insufficient evidence for it.
• To say that you believe something on faith is not
  to offer any justification for it in fact, you
  are admitting that you have no justification.
• Believing something on faith doesnt help us
  determine the plausibility of a proposition,
  faith cant be a source of knowledge.

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The Appeal to Intuition

• But the claim to know by intuition need not be
  construed as a claim to possess ESP. It can
  instead be construed as a claim to possess what
  might be called HSP hypersensory perception.
  Some people, like the fictional Sherlock Holmes,
  are much more perceptive than others. They
  notice things that others dont and consequently
  make inferences that others may think are
  unwarranted but really arent they are simply
  based on data that most people arent aware of.

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The Appeal to Mystical Experience

• Beyond the senses, beyond the intellect, beyond
  these mundane means we use to acquire knowledge
  lies a more direct path to truth mystical
  experience. So say many people who claim that
  mystical experience bypasses our normal modes of
  cognition and yields a deeper insight into the
  nature of reality.

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The Appeal to Mystical Experience

• Physicist Fritjof Capra, author of the
  best-selling The Tao Physics, argues that the
  mystics claim to knowledge cant be so easily
  dismissed because their vision of reality agrees
  with that of modern physics.
• The principal theories and models of modern
  physics, he says, lead to a view of the world
  which is internally consistent and in perfect
  harmony with the views of Eastern Mysticism.
  Mystics, like scientists, are seekers after
  truth. Whereas scientists use their senses to
  explore natures mysteries, mystics use only
  their intuition.

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The Appeal to Mystical Experience

• According to Capra and Lawrence LeShan (a
  psychologist), although the mystic and the
  scientist have traveled different paths, they
  have arrived at the same destination.
  Consequently, they claim, mystical experience
  must be considered a privileged source of
  knowledge.
• Capra cant claim that modern physics vindicates
  the worldview of Eastern mystics in general
  because the Eastern mystics dont share a common
  worldview. Hindus and Buddhists have radically
  different conceptions of the nature of reality.
• In fact, mystical worldviews seem to be at least
  as various as mystical traditions themselves.
  Mystics, even Eastern ones, do not speak with a
  single voice. Consequently, it cant coherently
  be maintained that modern physics confirms their
  view of things.

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Quantum Mysticism

• Quantum mysticismthe view that human
  consciousness determines the content of reality

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Capras assertion

• Quantum theory has confirmed the ancient view of
  Eastern mystics that human consciousness and the
  universe are one interconnected whole.

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Deepak Chopra is a better known mystical writer
with many best sellers
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Chopras ten bedrock assumptions of reality and
replacements

• According to Chopra, to achieve ageless body,
  timeless mind, we must replace ten bedrock
  assumptions from our current world view
• 1. There is an objective world independent of the
  observer.
• The physical world is a creation of the observer.

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Chopras ten bedrock assumptions and
replacements

• 2. The body is composed of clumps of matter
  separated from one another in time and space.
• The body is information and energy spanning the
  universe.
• 3. Mind and body are separate and independent
  from one another.
• Mind and body are one, resulting from a single
  creative source.

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Chopras ten bedrock assumptions and
replacements

• 4. We are physical machines that have learned to
  think.
• Thoughts and emotions create physical processes.
• 5. Human awareness can be completely explained by
  biochemistry.
• The world, including the experience of your body,
  is completely determined by how you learn to
  perceive it.

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Chopras ten bedrock assumptions and
replacements

• 6. As individuals, we are disconnected entities.
• Impulses of intelligence continually re-create
  your body every second.
• 7. Our perception of the world gives us an
  accurate picture of how things really are.
• All of us are connected to patterns of
  intelligence that govern the cosmos.

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Chopras ten bedrock assumptions and
replacements

• 8. Time is absolute. No one escapes its ravages.
• By perceiving changelessness, time ceases to
  exist.
• 9. Our true nature is totally defined by the
  body.
• Inside us is a field of non-change that creates
  who we really are.
• 10. Suffering is a necessary part of reality.
• Our spirit is immune to suffering or any form of
  change.

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The Appeal to Mystical Experience

• To preserve the view that all mystical experience
  yields knowledge, it has been claimed that
  although there are many different descriptions of
  mystical experience, the experience itself is the
  same for everyone.
• The different descriptions arise from the fact
  that mystical experience transcends our ordinary
  linguistic categories. Its so unlike any other
  experience weve had that we lack the words to
  describe it. Thus mystical experience is said to
  be ineffable.

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The Appeal to Mystical Experience

• If no description of mystical experience is true,
  however, there are no grounds for believing that
  its the same for everyone. Our only access to
  others experiences is through their descriptions
  of them. If these descriptions cant be trusted,
  we have no way of knowing whether their
  experiences are similar, for totally
  indescribable experiences cant be compared.

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The Appeal to Mystical Experience

• Most likely, what mystics mean by calling their
  experience ineffable isnt that it cant be
  described, but that the descriptions offered
  cant, by themselves, provide knowledge of what
  its like to have the experience.
• In this respect mystical experience are no
  different from any other experiences. Certainly
  it would be difficult to describe, for example,
  an orgasm to someone who had never had one. And
  simply reading a description of an orgasm wont
  normally produce one. To know what it is to have
  either an orgasm or a mystical experience, you
  simply have to have one.

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The Appeal to Mystical Experience

• While orgasms are relatively easy to induce,
  mystical experiences are relatively difficult.
  Those who have had mystical experiences have
  usually led lives of extreme self-denial and
  self-discipline.
• One effect of such behaviors is sensory
  deprivation, which is known to produce altered
  states of consciousness.
• Research indicates that the self-denial and
  self-discipline practiced by the mystics can have
  the same effect on the brain as hallucinogenic
  drugs.

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Hallucinogens and Mystical Experiences

• The Miracle of Marsh Chapel
• 2006 Johns Hopkins studies of Psylocibin

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The Appeal to Mystical Experience

• While being mystical doesnt guarantee the truth
  of an experience, it doesnt guarantee its
  falsity either. Its entirely possible that
  mystical experiences do reveal aspects of reality
  that are normally hidden to us. But the only way
  we can tell is by putting them to the test. If
  they are revelatory of reality, we should be able
  to corroborate them.

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Astrology Revisited

• There is simply no reliable data establishing any
  of astrologys claims.
• Not only is there no trustworthy evidence
  supporting astrology, but the very notion that
  stars and planets determine our physical and
  psychological makeup conflicts with a good deal
  of what we know about human physiology and
  psychology.

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Astrology Revisited

• It is the difficulty of explaining how stars and
  planets could possibly influence our
  personalities and careers that makes claims of
  astrology so hard to swallow.
• To the best of our knowledge, the universe
  contains only four forces gravity,
  electromagnetism, the strong nuclear force, and
  the weak nuclear force. Everything that happens
  in the world results from the action of one or
  more of these forces.
• The range of the strong and weak nuclear forces,
  however, is very limited they can only affect
  things in and around atoms. So if stars and
  planets affect us, it cannot be by their means.

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Astrology Revisited

• That leaves gravity and electromagnetism. Their
  range is potentially unlimited. But the strength
  of these forces diminishes the farther they get
  from their source. The gravitational and
  electromagnetic forces reaching us from the stars
  and planets are extremely weak. The book you are
  now reading, for example, exerts a gravitational
  force about a billion times greater at the point
  youre holding it than does Mars when it is
  closest to Earth.

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Astrology Revisited

• Accepting astrology would mean rejecting large
  tracts of physics, astronomy, biology, and
  psychology.
• When faced with such conflicts, the thing to do
  is to proportion our belief to the evidence.
• In the case of astrology, however, there is no
  evidence to proportion it to, for none of its
  claims has been verified. So the degree of
  belief it warrants is negligible.