How did science get started?

1. How did science get started? Michael Bass CREOL, The college of optics and photonics University of Central Florida Orlando, fl

2. Creation myths • Explanations for what we did not or could not understand. • Usually a God(s) would tire of doing nothing and to entertain him- or her- self create everything. • Then the God(s) would require of humans something in return for creating them such as: • Sacrifices • Prayers • Payments to the priests who interceded for the people with the Gods hence making the priests rich and powerful.

3. Events and regularities • Consider eclipses – eventually people realized that the sun would re-appear. • If you could count you could find that from the shortest day of the year to the next took 365 days. • The moon went from full to full again in 28 days. • Eclipses didn’t just occur randomly. • The ancient Babylonians could predict eclipses of the moon fairly accurately even if they didn’t know what caused them. • Another God related issue.

4. Calamities and non regularities Volcanoes Earthquakes Storms Floods Droughts And many other things that could not be understood. The common answer was that we must have offended the God(s). There were gods of love, sun, earth, sky, oceans, rivers, rain, storms, volcanoes and earthquakes to name a few. Keep them happy and all was well. Affront a god and a catastrophe ensued.

5. Was there science before the Greeks? • Modern humankind had been around for ~200,000 years and must have done something. • Lets list some of those achievements. • Starting with making fire and stone tools. • 28,000 BC – marks carved on a bone seem to represent the moon’s course over 2.5 months. • What next? • Was all of this science or an accumulation of technologies?

6. The beginning in Greece • About 9000 years ago the first written languages appear. • This was necessary for record keeping and rationing out bread and beer. • Near 600 BC Thales of Miletus suggested that things may follow consistent principles that humans could figure out. • With this concept, science began the long path to ending the roll of God(s) and establishing the roll of science in understanding the universe. • Since the first modern humans appeared about 200,000 years ago, science has been developing for only 1% of that time and yet • look how far we have come! • During the first 198,000 years we did learn to make stone tools, gold, copper, brass, iron and steel, boats, wheeled vehicles, farms, domesticate animals and so on. This body of knowledge could be called science but was not thought of as a connected body of knowledge and no connections were made.

7. Science in Ancient Greece About 900 BC the first written Greek records are found. It takes over 300 years before Thales has his insight into the universe even if he doesn’t know it. In fact it was Aristotle (384 to 322 BC) who pointed this out and expanded on it; Thales idea was that complex events could be explained in terms of simpler events and eventually in terms of general principles. No myths or Gods were required, just human intelligence.

8. Rational thinking and the use of logic • The goal of science since Thales has been to uncover fundamental laws to explain natural phenomena. • This is a major milestone in human thought. • It might be possible for us to understand what before had been up to the Gods. • This rational approach allowed the Greeks to reach many conclusions that seem to be very much the basis of modern science. • The first mathematical formulation to come from this approach was by Pythagoras (580 to 490 BC) when he developed the Pythagorean theorem relating the lengths of the sides of right triangles. • This simple mathematical formula is the first instance of theoretical physics.

9. Anaximander (610 to 546 BC) Was a friend of Thales (maybe even a student of Thales). Anaximander observed that human infants are helpless. If not cared for by parents they would die. Hence, he reasoned people must have evolved from other animals with sturdier young. This is the first inkling of Darwin’s Theory of Evolution.

10. Empedocles (490 to 430 BC) Performed an experiment to show that there was air. Used a device roughly spherical in shape with holes in the bottom and a hole on top. When submerged in water it filled up and when you withdrew it, it emptied. If you covered the top hole with your finger and withdrew it the water did not run out. If you covered the top hole when submerging it the water did not get in. Something must be holding the water in or preventing it from getting in. The something was air. Notice the use of logic when interpreting an experiment. A very simple experiment with very major implications

11. Democritus (460 to 370 BC) • What happens if you cut something in pieces? • And cut the pieces again. • If you kept this up you would eventually have pieces you could not cut up. • He postulated from such thinking that all things including us are made of fundamental particles that can not be cut into smaller pieces. • From logical reasoning and no experimental evidence he started atomic physics. • He named these particles “atoms” from the Greek word for “un-cuttable”. • He even went so far as to postulate that these particles moved forward indefinitely. • This eventually led to the law of inertia.

12. Aristarchus (310 to 230 BC) • By observation and calculation he concluded that we humans were not so special and at the center of the universe. • By observing the size of the earth’s shadow on the moon during a lunar eclipse he concluded that the sun must be much larger than the earth. • If tiny objects orbited huge objects we were not at the center. • He was just a small step from the Copernican concept of our place in the solar system. • He even argued that the stars were just very distant suns. • A very modern concept indeed.

13. Euclid (323 to 283 BC) • Brilliant mathematician. • Identified small set of axioms. He postulated: • "To draw a straight line from any point to any point." • "To produce [extend] a finite straight line continuously in a straight line." • "To describe a circle with any centre and distance [radius]." • "That all right angles are equal to one another." • The parallel postulate: "That, if a straight line falling on two straight lines make the interior angles on the same side less than two right angles, the two straight lines, if produced indefinitely, meet on that side on which are the angles less than the two right angles." • and developed what we now call Euclidean geometry. • Plane geometry • Also wrote works on conic sections, spherical geometry, number theory and rigor in arguments. • Established the concept of rigorous proofs for mathematical truths.

14. Archimedes(287 to 212 BC) • Archimedes formulated three of the most important laws of physics still in use today: • The law of levers! • The law of buoyancy! • The law of reflection of light! • Perhaps he should be honored here in the College of Optics and Photonics? • He did not treat them as laws or explain them by measurement or observation. • He considered them purely mathematical theorems.

15. Not accepted The concepts suggested that there was no room for free will or for the Gods in the universe. All was to be determined by these laws. Epicurus (341 to 270 BC) argued against atomism because it is “better to follow the myths about the gods than to become a slave to the destiny of natural philosophers.” Aristotle also objected that human beings could not be composed of soulless inanimate objects. He also set in place the model of the cosmos that held sway for nearly 2000 years.

16. Was this Science? • They had not invented the scientific method so they did not have the goal of experimental verification. • The interesting concepts were not to be tested. • They never really separated the concept of God from their concepts of science. • For example, Heraclitus (535 to 475 BC) claimed that the sun behaved as it does because if it didn’t the goddess of justice would punish it. • They used human behavioral concepts to deal with the physical world. • The rules needed to be enforced so that the objects obeyed.

17. It wasn’t science but It gave us logic. The use of mathematics to describe how things worked. Because precise measurements and calculations were difficult they made very few. However, they did know the earth was a sphere, they had Pythagoras’ theorem, Archimedes principle, the law of levers and light reflection and Euclid’s geometry. These tools were crucial to the development of science and helped develop technology but were not science as we know it.