Introducing the Philosophy of Science Lecturer: Vincent Zungu - - PowerPoint PPT Presentation

Introducing the Philosophy of Science

Lecturer: Vincent Zungu Source: Chalmers, A.F. 2005. What is this thing called Science. Open University

• Press. Maidenhead.

“Unprejudiced seeing?”

• Two people viewing the same object do not

always see the same thing. Figure 1 on page 6.

• What do you see? Is it a staircase or just a

collection of lines. If it is a staircase, is it

• ne from above or below?

Observation: passive and private

• r public and active
• How observation is commonly understood

by philosophers?

• What is observation as passive and private
• r public and active affair?
• What is the role of observation in Science?

Observation: passive and private

• r public and active
• Common understanding of observation by

range of philosophers: seen as passive, private affair.

• Passive – when seeing we simple open and

direct our eyes, let the information flow in, and then record what is there to be seen.

• Private – it is the perception itself in the

mind that is taken to directly validate the

• bservable facts.

Observation: passive and private

• r public and active
• Example – One can see that an object in

front of his is a Tomato!

• Note- the above act is accomplished by

individual closely attending to what is presented to him/her in the act of percetion

• However- it does not provide an accurate

account of perception in everyday life or even in science.

• There are range of things that are done to

establish the validity of perception.

Observation in Science Public and Active

• Our task is to consider the role of
• bservation in science.
• E.g. the early use of microscope in science.
• Robert Hooke and Henry Powers used the

microscope to look at the small insects and ants.

• These scientists often disagree about
• bservable facts initially. Hooke traced the

nature of the disagreements.

Observation in Science Public and Active

• He pointed out that the eye of a fly appears

like a lattice covered with holes in one kind

• f a light.
• Powers agreed but also mentioned that it

appears like a surface covered with cones in another and in yet another light like a surface covered with pyramids.

– Important to note that above scholars sees the same objects but with different descriptions. – The question: is which one of these provides accurate description?

Observation in Science Public and Active

• Hooke then proceeded to make practical

intervention designed to clear up the

• problem. How?
• Eliminate spurious information arising from

dazzle and complicated reflections by illuminating specimens uniformly.

• Micrographia (1665) book came out with

many detailed descriptions and drawings that resulted from Hooke’s actions and

• bservations.

Observation in Science Public and Active

• These productions were and are public, not

private.

• They can be checked, criticised and added to

by others.

• Therefore the observable facts about the

structure of a fly’s eye that eventuate result from a process that is both active and public.

• If actions are taken to explore the validity of

claims – thus subjective aspects of perception need not to be a problem for science

Observation in Science

• Perceptions of the same scene can vary

from observer to observer – their background, culture and expectations.

• This problem can be eliminated by taking

appropriate action.

• The perceptual judgements of individuals

can be unreliable for a range of reasons.

• Challenge: in science is to arrange the
• bservable situation in way that the reliance
• n such judgments is minimised.

Observation in Science

Vertical View Horizontal View

Observation in Science

• Moon illusion is a common phenomenon.
• High in the sky – appears much smaller

than when it is low on the horizon.

• However – do not have to put trust on the

subjective judgement about the moon size

• But what do we do to reduce subjective

view of the moon size.

• Can mount a sighting tube fitted with cross

wires – so that its orientation can be read on a scale.

Observation in Science

• This can be done when the Moon is high on

the sky and repeatedly done when it is horizontal.

• Findings- the moon remain unchanged –

indicating that there is no significant variations and differences between the scale readings in two cases.

Observation in Science

• Key points to learn:
• Observation statement constitute worthy of

forming basis for science – straightforwardly tested by senses and withstands those tests.

• OS – their validity can be tested in ways

that involve routine, objective procedures that do not necessitate fine, subjective judgements on the part of observer.

• This brings out the Active, public character
• f the vindication of OS.

Observation in Science

• Small price has to be paid for the notion of

an observable fact (OF).

• That price is that (OF) are to some degree

fallible and subject to revision.

• If OF passed the testes – does not mean that

it will survive new kinds of tests that become possible in the light of advances in knowledge and technology.

• E.G. The earth is Stationary and second –

the apparent size of Mars and Venus do not change appreciably during the course of the year.

Observation in Science

• Therefore we can conclude that observation

worthy of forming basis for scientific knowledge are both objective and fallible.

• Objective – because they can be publicly

tested by straightforward procedures And

• Fallible – they may be undermined by new

kinds of tests made possible by advances in science and technology

Essay Question ?

• Discuss how observation statement can

form the basis for scientific knowledge. Answer your question by providing relevant examples to show understanding of the

• topic. (Essay must be 5 pages!!!). Due date:

15 August 2011)