How Do You Know?

This introductory lecture for Freshman Organic Chemistry covers course logistics, the philosophical foundations of scientific inquiry, and the historical development of experimental logic.

Course logistics and student support

Organic chemistry has a long-standing reputation for being a daunting subject, and even able students will need significant help to succeed. To that end, several resources are provided. PowerPoint presentations used in lectures can be downloaded from the course website so students can focus on discussion rather than transcription. Though created on a Mac, they are designed to work on PCs and free PowerPoint viewers.

The course website serves as a substitute for a traditional textbook and includes lecture notes, assigned problems, and an archive of previous exams and answer keys. A unique feature is the Wiki, now in its third year of systematic use: students are assigned specific frames from the PowerPoints to write up and explain, contributing to a collective learning resource. To receive credit, Wiki entries must be completed within 36 hours of the lecture so other students can benefit from them immediately.

Personalized assistance is a priority. The instructor posts his contact information on the website, and two graduate teaching assistants—Filip Kolundzic and Nathan Schley—run discussion sections. These are flexible; students can attend any of the two-hour night sessions regardless of which section they officially signed up for. Additionally, peer tutors—seniors who took the course as freshmen—hold sessions on Sunday evenings. Students are strongly encouraged to form study groups and consult advice from course veterans posted online. Grading is based on 650 total points: three exams plus 50 points for Wiki participation.

The goals of organic chemistry

The primary academic goals of the first semester are to learn the vocabulary of the field and to develop a theoretical intuition regarding bonding, molecular structure, and reactivity. Equally important, though, is the "scientific transition" from school to university: primary school often focuses on learning what is already known, while university education aims to teach students how to develop new knowledge.

A creative scientist must learn to be "astonished" by the unexpected—a sentiment echoed by Louis Pasteur, who noted that astonishment is the first step toward discovery. The lecture contrasts the famous "Eureka!" moment with the more common scientific observation: "Huh, that's funny." By forming a solid mental picture of how chemistry works, students can recognize when something does not fit, leading to genuine discovery. The course also aims to help students develop "good taste" to distinguish scientific sense from nonsense by examining high-quality examples of research.

How do you know? Four ways of knowing

A central theme of the course is the question: "How do you know?" There are four primary ways people acquire knowledge:

1. Divine authority — receiving truth from a higher power, exemplified by Moses on Mount Sinai.
2. Human authority — accepting the interpretations of experts or scriptures.
3. Experimental observation — learning through direct experience and testing.
4. Logic — using reasoning to reach conclusions.

While the first two forms of authority may exist in other realms, science is not faith-based and must ignore both divine and human authority in favor of evidence. Michael Faraday, a leading experimentalist of the 19th century, illustrates the shift toward experiment. Despite a humble background as a bookbinder's apprentice, Faraday taught himself chemistry by reading and performing the experiments in Jane Marcet's Conversations on Chemistry. He famously said that while he was imaginative, "facts were important to me and saved me," leading him to cross-examine every assertion through experiment.

Physicist Richard Feynman reinforced this, stating that "science is the belief in the ignorance of experts." For Feynman, the phrase "science has shown" is often a misuse of the word; instead, one should ask how an experiment or effect showed a specific result. In this course, the lecture focuses on logic while the lab focuses on experiment—both necessary for a balanced understanding.

The 17th century and the birth of modern science

Modern science began to flourish in the 17th century, a period Robert Hooke described as the most "inquisitive" of all ages. This era saw the work of Francis Bacon, who sought a "Great Restoration" (Instauratio Magna) of knowledge. Bacon criticized his Cambridge tutors for being "shut up in their cells" with a few ancient authors like Aristotle. He argued that traditional philosophy was like the "boyhood of knowledge"—it could talk but could not "generate" or produce anything of practical use.

Bacon proposed the inductive scientific method, which replaced Aristotelian deduction with systematic experimentation. He used the metaphor of the Pillars of Hercules (the mouth of the Mediterranean) to represent the limits of the old Classical world. Just as explorers sailed beyond these pillars to find the New World, scientists must go "plus ultra" (more beyond) to increase knowledge through experiment.

This philosophy led to the founding of The Royal Society in 1662. Its motto, Nullius in Verba ("in the words of none"), underscores that scientists are not bound by the oath of any master or philosopher—instead, they follow where the experiment leads. Early chemistry in the Royal Society was often driven by practical needs, such as the government's desire for better gunpowder and improved navigation.

Crucial experiments and logic

Bacon identified a specific type of experiment that "finally decides between two rival hypotheses"—he called this a "crucial experiment." The word "crucial" comes from the Latin crux (cross), referring to a signpost at a crossroads that tells a traveler which way to go. Isaac Newton's prism experiment is a classic Experimentum Crucis. At the time, thinkers like Hooke and Descartes believed the prism itself created colors by altering light pulses. Newton hypothesized that colors were pre-existing and the prism merely separated them. By isolating a single color (red) and passing it through a second prism, he showed that the "broken light does not change its color" (nec variat lux fracta colorem), proving his theory.

The lecture also highlights intellectual honesty through the story of Samuel Pepys and Isaac Newton. Pepys, though a high-ranking official and President of the Royal Society, was not ashamed to admit his ignorance. He spent hours learning the multiplication table at age 30 and later sought Newton's help with a gambling problem involving dice probabilities. When Newton provided a solution showing that "A" had a better chance of winning than "B" or "C," Pepys did not simply accept the answer. He insisted on seeing the computation because he "cannot bear the thought of being made master of a jewel I know not how to wear." This persistence in seeking solid understanding over rote memorization is the model for success in the course.

The foundations of atoms and forces

The lecture concludes by introducing the physical nature of atoms and the forces that hold them together. Robert Boyle, an early member of the Royal Society, explored the "Spring of Air," demonstrating that air in a piston acts like a physical spring (Boyle's Law). Robert Hooke expanded on this by publishing a theory of elasticity, though he initially hid it in an anagram (ceiiinosssttuv) to prevent others from stealing his idea. Unscrambled, the Latin reads Ut tensio sic vis ("as the extension, so the force"). Known as Hooke's Law, this principle states that the force of a spring is proportional to its distortion. The idea of potential energy being proportional to the square of the extension (a parabola) serves as a foundational tool for understanding chemical bonding in the sessions to follow.