Ridling Zaine. Philosophy: Then and Now. A look back at 26 centuries of thought

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Ridling, Philosophy Then and Now: A Look Back at 26 Centuries of Thought

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is inconsistent even though it may not be explicitly contradictory. For

example, the negation of “The whole is greater than any proper part” is not

explicitly contradictory in the way that “Snow is white and snow is not white”

is; nonetheless, “The whole is not greater than any proper part” cannot

possibly be true and hence is contradictory.

The second class of certainly known propositions consists of things

knowable through experience, where “experience” has the Aristotelian sense

of something that is encountered numerous times. The knowledge afforded by

experience is grounded in the a priori epistemic principle that “whatever

occurs in a great many instances by a cause that is not free is the natural effect

of that cause.” It is important to note that Duns Scotus’ pre-Humean

confidence in induction did not survive the Middle Ages. The 14th-century

philosopher Nicholas of Autrecourt, who has been called “the medieval

Hume,” argued at length that there is no necessary connection between any

two events and that there is no rational justification for the belief in causal

relations.

The third class of certainly known propositions consists of things

knowable that concern one’s own actions (de actibus nostris). Humans know

when they are awake immediately and not through any inference; they know

with certainty that they think (me intelligere) and that they hear and have

other sense experiences. Even if a sense experience is caused by a defective

sense organ, it remains true that one is aware of the sensuous content of the

sensation: for example, one sees white even if one is mistaken in thinking that

the seeing is caused by snow.

The fourth class of certainly known objects consists of things knowable

through human senses (per sensus). Duns Scotus said that humans learn about

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the heavens, the earth, the sea, and all that are in them. This last class of

objects that are certainly known things seems to be posited without regard to

the threat of Scepticism at all.

Duns Scotus’ rendition of intuitive knowledge, however, has the purpose

of forestalling the sceptical move of interposing something between the

knower and the thing known that might enable belief to deviate from its

object. Intuitive knowledge is indubitable knowledge that something exists. It

is knowledge “precisely of a present object [known] as being present and of

an existent object [known] as being existent.” Further, the object of

knowledge must be the cause of the knowledge. If a person sees Socrates

before him, then, according to Duns Scotus, he has intuitive knowledge of the

proposition that Socrates is white and that Socrates and his whiteness cause

that knowledge. Intuitive knowledge contrasts with abstractive knowledge,

such as knowledge of universals, for which the object need not be present or

even existent. For example, for all one knows from contemplating the nature

of dogs or unicorns, they are equally likely or unlikely to exist.

It may appear that intuitive knowledge is absolute; either one has it or

one does not. But that is not Duns Scotus’ doctrine. He held that there is

imperfect intuitive knowledge of the past, which is more certain than

abstractive knowledge but less certain than present intuitive knowledge.

However plausible or implausible this may be, it is worth noting that Russell

held the same view but expressed it by using the terms “knowledge by

acquaintance” (intuitive cognition) and “knowledge by description”

(abstractive cognition).

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William of Ockham

There are several places in Duns Scotus’ account where sceptical

challenges can gain a foothold, for example, when he endorses the certainty of

sense knowledge and when he holds that intuitive cognition must be of an

existent object. William of Ockham (c. 1285-1349?) took his stand against the

sceptical challenge by radically revising Duns Scotus’ idea of intuitive

cognition. Unlike Duns Scotus, Ockham does not require intuitive knowledge

to have an existent object, and the object of intuitive knowledge need not be

its cause. To the question “What is the basis for the distinction between

intuitive and abstractive knowledge?” given that it is not the existence of the

object and not a causal relation between an object and the knower, Ockham

answered that they are simply different. His answer notwithstanding, it is

characteristic of intuitive knowledge that it is unmediated. There is no gap

between the knower and the known that might undermine certainty: “I say that

the thing itself is known immediately without any medium between itself and

the act by which it is seen or apprehended.”

According to Ockham, there are two kinds of intuitive knowledge:

natural and supernatural. In natural intuitive knowledge, the object exists, the

knower judges that the object exists, and the object causes the knowledge. In

supernatural intuitive knowledge, the object does not exist, the knower judges

that the object does not exist, and God is the cause of the knowledge. In

neither case is knowledge a relation; it is something a person has, a property

of the person.

Ockham recognized that God might cause a person to think that he has

intuitive knowledge of an existent object when there in fact is no such object.

But such a condition is not intuitive knowledge but a false belief.

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Unfortunately, in acknowledging that a person has no way to distinguish

between genuine intuitive cognitions and divine counterfeits of them, Ockham

has in effect lost the argument to the Sceptics.

Later medieval philosophy followed a fairly straight path to Scepticism.

John of Mirecourt was condemned in 1347 for holding among other things

that there is no certainty of external reality because God could cause illusions

to seem real. Nicholas of Autrecourt was also condemned in the same year for

holding that only purely sensory reports of human experience are certain and

that the only certain principle is that of contradiction, namely, that a thing

cannot be and not be something at the same time. He denied that humans

know that causal relations exist or that there are substances, two of many

errors he credited to Aristotle, about whom he said, “In all his natural

philosophy and metaphysics, Aristotle had hardly reached two evidently

certain conclusions, perhaps not even a single one....” The link between

Scepticism and criticism of Aristotle was fairly strong, and Petrarch, in On My

Ignorance and That of Many Others (1367), cited Aristotle as “the most

famous” of those who do not have knowledge.

From Scientific Theology to Secular Science

For most of the Middle Ages there was no split between theology and

science (scientia). Science was knowledge that was deduced from self-evident

principles, and theology received its principles from the source of all

principles, God. In every way, theology was superior to the other sciences,

according to Thomas Aquinas. By the 14th century the ideas of science and

theology began to be separated. Roughly, theologians began to argue that

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human knowledge was much more narrowly circumscribed than earlier

believed. They often exploited the omnipotence of God in order to undercut

the arrogance and pretension of human reason. Their motive was to enhance

the dignity of God at the expense of human reason, and in place of rationalism

in theology, they promoted a kind of fideism.

Gregory of Rimini (c. 1300-c. 1358) exemplified the growing split

between natural reason and theology. According to Gregory, theology is not a

science, and theological propositions are not scientific. In the new view of

Gregory, who was inspired by Ockham, science deals only with what is

accessible to humans through natural means, that is, through the ordinary

operations of their senses and intelligence. Theology in contrast deals with

what is accessible in some supernatural way. Thus, theology is not scientific.

The role of theology is to explain the meaning of the Bible and the articles of

faith and to deduce conclusions from them. Since the credibility of the Bible

rests upon belief in divine revelation and revelation upon the authority of God,

theology lacks a rational foundation. Further, since there is neither self-

evident knowledge of God nor any natural experience of him, humans can

have only an abstract understanding of what he is.

Ockham and Gregory did not at all intend their views to undermine

theology. For them, natural science is built on probabilities, not certainties.

Since humans are fallible, their natural science is fallible, unlike theology,

which is built upon propositions that have the authority of God. Unfortunately

for theology, the prestige of natural science rose in the 16th century and

skyrocketed in the 17th and 18th centuries; modern thinkers preferred coming

to their own conclusions based upon experience and reason, even if these were

only probable, to trusting the authority of anyone, even God. (This attitude has

been called “the Faustian ethos,” after Goethe’s character Faust.) As the

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theologians tended to lose confidence in reason, other thinkers who had no or

virtually no commitment to Aristotelian thought became the champions of

reason and helped give birth to modern science.

Modern Philosophy

Faith and Reason

Modern philosophers as a group are usually thought to be purely secular

thinkers. Nothing could be further from the truth. From the early 17th century

until the middle of the 18th century, all of the great philosophers incorporated

substantial religious elements into their work. Descartes, in his Meditations

(1641), offered two different proofs for the existence of God, and he asserted

that no one who does not believe in a cogent proof for the existence of God

can have knowledge in the proper sense of the term. Benedict Spinoza began

his Ethics (1677) with a proof for the existence of God, after which he

expatiated on its implications for understanding all reality. And George

Berkeley explained the stability of the sensible world by relying upon God’s

constant thought of it.

Among the reasons modern philosophers are mistakenly thought to be

primarily secular thinkers is that many of their epistemological principles,

including some that were intended to defend religion, were later interpreted as

subverting the rationality of religious belief. The role of Thomas Hobbes

(1588-1679) and John Locke might be briefly considered in this connection.

In contrast with the standard view of the Middle Ages that propositions of

faith are rational, Hobbes argued that propositions of faith belong not to the

intellect but to the will. To profess religious propositions is a matter of

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obeying the commands of a lawful authority. One need not even understand

the meanings of the words professed: an obedient mouthing of the appropriate

confession of faith is sufficient. In any case, the linguistic function of virtually

every religious proposition is not cognitive in the sense of expressing

something that is intended to represent a fact about the world but rather to

give praise and honour to God. Further, in contrast to the medieval view,

according to which theology is the highest science, theology is not a science at

all since its propositions are not susceptible to rational dispute.

In An Essay Concerning Human Understanding (1689), Locke further

eroded the intellectual status of religious propositions by making them

subordinate to reason in several dimensions. First, reason can dictate what the

possible content of a proposition allegedly revealed by God might be; in

particular, no proposition of faith can be a contradiction. Consequently, if the

proposition that Jesus is both fully God and fully man is contradictory, it

cannot be revealed and cannot be a matter of faith. Also, no revelation can be

communicated that contains an idea not based upon sense experience. Thus,

St. Paul’s experience of things “as eye hath not seen, nor ear heard, nor hath it

entered into the heart of man to conceive,” are things in which other people

can have no faith. To move to another dimension in which reason takes

precedence over faith, direct sense knowledge (what Locke calls “intuitive

knowledge”) is always more certain than any alleged revelation. Thus, a

person who sees that someone is soaking wet cannot have it revealed to him

that the person is at that moment dry. Rational proofs, in mathematics and

science, also cannot be contradicted by divine revelation. The interior angles

of a rectangle equal 360, and no alleged revelation to the contrary is credible.

In short, “Nothing that is contrary to, and inconsistent with, the clear and self-

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evident dictates of reason, has a right to be urged or assented to as a matter of

faith....”

What space, then, does faith occupy within the mansion of human

beliefs? According to Locke, it shares a room with probable truths, those

propositions of which reason cannot be certain. There are two types: claims

about observable matters of fact and claims that go “beyond the discovery of

our sense.” Religious propositions belong to each category, as do empirical or

scientific ones. That Caesar crossed the Rubicon and that Jesus walked on

water belong to the first type of probable proposition. That heat is caused by

the friction of imperceptibly small bodies and that angels exist are

propositions that belong to the second category.

While mixing religious claims with scientific ones might seem to secure

a place for the former, in fact it did not. For Locke also held that whether

something is a revelation or not “reason must judge,” and more generally that

“Reason must be our last judge and guide in everything.” Although this

maxim was intended to reconcile reason and revelation – indeed, he calls

reason “natural revelation” and revelation “natural reason enlarged by a new

set of discoveries communicated by God” – over the course of 200 years

reason repeatedly judged that alleged revelations had no scientific or

intellectual standing.

Although there is a strong religious element in modern thinkers,

especially before the middle of the 18th century, the purely secular aspects of

their thought predominate in the following discussion, because it is these that

are of contemporary interest to epistemologists.

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Impact of Modern Science on Epistemology

Nicolaus Copernicus (1473-1543), a cleric, argued in On the Revolutions

of the Celestial Spheres (1543) that the Earth revolves around the Sun. His

theory was epistemologically shocking for at least two reasons. First, it goes

directly counter to how humans experience their relation to the Sun; it is

everyone’s prescientific view that the Sun revolves around the Earth. If

science can overthrow such a belief, then scientific reasoning seems to lead to

knowledge in a way that nonscientific reasoning cannot. Indeed, the

nonscientific reasoning of everyday life may seem to be a kind of superstition.

Second, his theory was shocking because it contradicts the view that is

presented in several books of the Bible, most importantly the explicit account

in Genesis of the structure of the cosmos, according to which Earth is at the

center of creation and the Sun hangs from a celestial ceiling that holds back

the waters which once flooded the Earth. If Copernicus is right, then the Bible

can no longer be taken as a reliable scientific treatise. Scientific beliefs about

the world, then, must be gathered in a radically new way.

Many of the discoveries of Galileo Galilei (1564-1642) had the same

two shocking consequences. His telescope seemed to reveal that unaided

human vision gives false or seriously incomplete information about the nature

of celestial bodies. His mathematical formulations of physical phenomena

seem to indicate that most sensory information may contribute nothing to

knowledge. Like his contemporary, the astronomer Johannes Kepler, he

distinguished between two kinds of properties. Primary qualities, such as

shape, quantity, and motion, are genuine properties of things and are

knowable by mathematics. Secondary qualities, namely, odour, taste, sound,

color, warmth, or coldness, exist only in human consciousness and are not part

of the objects to which they are normally attributed.

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René Descartes

Both the rise of modern science and the rediscovery of Scepticism were

important influences on René Descartes (1596-1650). While he believed that

humans were capable of knowledge and certainty and that modern science

was developing the superstructure of knowledge, he thought that Scepticism

presented a legitimate challenge that needed an answer, one that only he could

provide.

The challenge of Scepticism, as Descartes saw it, is vividly portrayed in

his Meditations. He considered the supposition that all of one’s beliefs are

false, being the delusions of an evil genius who has the power to impose

beliefs on people unbeknownst to them. But Descartes claimed that it is not

possible for all of one’s beliefs to be false, for anyone who has false beliefs is

thinking and knows that he is thinking, and if the person is thinking, then that

person exists. Nonexistent things cannot think. This line of argument is

summarized in Descartes’s formula, “Cogito, ergo sum” (“I think; therefore, I

am”).

Descartes distinguished two sources of knowledge: intuition and

deduction. Intuition is an unmediated mental seeing or direct apprehension of

something experienced. The truth of the proposition “I think” is guaranteed by

the intuition one has of one’s own experience of thinking. One might think

that the proposition “I am” is guaranteed by deduction, as is suggested by the

“ergo.” In Objections and Replies (1642), however, Descartes explicitly says

that the certainty of “I am” is also based upon intuition.

If one could know only that one thinks and exists, human knowledge

would be depressingly narrow. So Descartes proceeded to broaden the limits