Biological Anthropology the nature of science

Some Terms used in Science Hypothesis: a statement that potentially explains specific phenomena – must be falsifiable Data: evidence that helps answer questions and problems Empirical: referring to data obtained through observations and/or experimentation Theory: a set of hypotheses – explanatory principles – that have not (yet) been falsified

Science is … a process that develops provisional truths That is, “truths” that may one day be replaced by better “truths”

Science is not… a process that develops absolute truths That is, TRUTHS that may not be questioned and can never be corrected or improved upon

Two Assumptions of Science 1)You explain natural phenomena only by referring to other natural phenomena Methodological materialism 2) If two models both explain the data, use the simplest (unless you have a reason not to) OCCAM’S RAZOR (which is NOT the same as Philosophical Materialism)

Science can be understood as a process of “modeling” reality reality

A Theory Emerges the first model does not explain some aspects of its focus predicts outcomes that will not occur x + 1 = y

Science Advances a second, “better” model unexplained phenomena predicted, but not “real” x 2 + 2z = 0

Comprehension Increases another, even “better” model predicted, but not “real” unexplained phenomena

Science as the Quest for ever “better” models

Is there a “perfect” model? explains all phenomena that do exist predicts nothing that does not exist

Not yet…

Science as a revolutionary process “normal” science anomalies scientific “revolution”

The Copernican Revolution the shift from a geocentric (“earth-centered”) to a heliocentric (“sun-centered”) model of the solar system

Geocentric Worldview Earth was immobile All celestial objects revolve around the earth Sun Moon (fixed) stars Planets, comets, etc. Aristotelian physics divided the heavenly region from the earthly region (= perfection vs. corruption)

Science takes place in a Social Context Geocentrism was central to early Christianity Universe created for humans Humans are the reason for creation Challenging the geocentric view was heresy Heresy was a very serious offense

The Retrograde Mystery

Two Different Explanations The Geocentric ViewThe Heliocentric View Different celestial objects move in very different ways The Earth moves in the same way as other celestial objects

Nicholas Copernicus Physician, lawyer, church administrator De Revolutionibus Orbium Coelestium (“On the Revolutions of the Celestial Orbs”) published in 1543

Heliocentric Worldview the planets all move in a similar manner Heliocentrism makes fewer assumptions has greater applicability the movements of celestial objects can be explained and predicted Retrograde Mars (and Uranus) Credit & Copyright: Tunc Tezel

But acceptance was slow, as heliocentrism seemed absurd If the earth is moving, how can a stone that is thrown straight up come straight down? If the earth is a planet, why is it the only one with a moon? If the earth did move, why did the relative positions of the stars not (why would space be that big?)

Galileo Galilei Born 1564 Begins studies at University of Pisa in – appointed professor of mathematics at University of Padua

Galileo Galilei 1609 – makes his first telescope Discovers Sunspots Rings of Saturn Phases of Venus Satellites of Jupiter Galileo’s notes of his observations of Jupiter and its moons; January 1610

Galileo Galilei Dialogue Concerning the Two Chief World Systems (1633) Condemned by the Roman Inquisition in 1633 Under house arrest from 1633 until his death in 1642

Galileo Galilei Pope John Paul II orders a review of the case against Galileo Initial report states that Galileo was wrongly condemned 1989 – Pope acknowledges “imprudent” action of Church

Science as a revolutionary process “normal” science – sun goes around earth anomalies – planetos the “revolution” – earth goes around sun

Another Scientific Revolution Antoni van Leeuwenhoek ( ) Some of van Leeuwenhoek’ instruments (replicas)

The first image of microbes (1683) (the dotted line between C and D indicates motility) Spermatozoa by van Leeuwenhoek originally published in Philosophical Transactions,

Van Leeuwenhoek’s Work would ultimately lead to Robert Koch ( ) Louis Pasteur ( ) Joseph Lister ( ) the discovery that microscopic organisms can cause illness and death

Things to remember Scientific discovery is driven by the community of scientists; they actively look for problems with theories Scientific discoveries often contradict cherished notions of what the world is like Scientific truths are provisional, as better models are continually being pursued Science is a self-correcting process