Francis Bacon on the New Science (1620) 1. Clearing Away Idols: During Bacon’s time, medieval science was still alive and well (but not for long). For instance, in Bacon’s time, most still believed in: - Geocentrism: The Sun goes around the Earth. - Spontaneous Generation: Life arises spontaneously in nature. - Alchemy: It is possible to turn various metals into gold. - Magic: For instance, magnets were thought to be proof that magic existed. And the public regularly sought the use of amulets, astrology, and other superstitious and supernatural sources for healing, etc. - Bloodletting: Illness is caused by an imbalance in the “four humors”. For instance, a fever is caused by too much blood—and is curable by bleeding the patient. (Fun aside: The terms sanguine (blood), melancholic (black bile), choleric (yellow bile), and phlegmatic (phlegm), are derived from a time when it was thought that these were four personality types were caused by the quantities of these humors.) Bacon argues that science had been, up to that point, pretty much rubbish—founded mostly on opinion, dogma, and superstition. It was rarely able to make good predictions, and it had become very common, in the face of observations contradicting the going theory, to simply revise that theory in an ad hoc way rather than throwing it out and searching for a new hypothesis. (The theory of epicycles is famous for this.) But Bacon was living in the midst of a scientific revolution (of which he was a major player). For instance, the Copernican model (of heliocentrism), published in 1543, would finally become widely accepted shortly after this writing from Bacon. And the rest of the list above would slowly be rejected over the coming century or two. Brief timeline of some notable events 1543 – Copernicus publishes (as he dies) his proposal that the Earth orbits the Sun 1609 – Telescope invented 1610 – Galileo discovers the moons of Jupiter and the phases of Venus 1616 – Galileo officially warned by the church to stop defending the Copernican system 1609-1619 – Kepler, using Brahe’s observations, publishes his laws of planetary motion 1620 – Bacon publishes his proposal for a new scientific method 1633 – Galileo arrested for the heresy of defending the Copernican system 1641 – Descartes’ Meditations 1665 – Hooke discovers the cell (after microscope developments from 1620 – 1644) 1672 – Newton discovers light is a spectrum of the colors 1687 – Newton publishes his laws of gravitation 2. Confirmation Bias: Why so much error? Before answering, let’s do an experiment. I have a mathematical rule about sequences of numbers in mind, and I want you to guess it. Before we begin, I’ll give you an example of a sequences that follows my rule: {2, 4, 8} Your task is to guess my rule. Before making your guess, you’ll be allowed to state any sequence of numbers you want, and I’ll tell you either “Yes, it follows my rule” or “No it doesn’t”. You may do this for as long as you like. Once you’re satisfied that you know what rule I have in mind, you can guess what my rule is. How would you proceed? Most people proceed as follows: {8, 16, 32} yes {16, 32, 64} yes And so on; and ultimately guess something like “factors of 2” or “multiples of 2”. What’s weird is that nearly always, EVERYTHING they ask is something that they expect the answer to to be “yes”—they never ask something where they expect the answer to be “no”. Yet, falsification is far more informative than confirmation. (Watch an excellent video describing the phenomenon here.) [Spoiler: Scroll to the end to see my rule.] [Why would we think that falsification is more conclusive than confirmation? Consider: If my model or hypothesis predicts that X will happen, and X does NOT happen, we know for sure that my hypothesis is false. But, what should we say if X DOES happen? Perhaps we’re justified in raising our level of confidence in that hypothesis but we still haven’t shown CONCLUSIVELY that it is correct. To see why just consider: According to the theory of spontaneous generation, if I leave this rotten meat out overnight, there will be maggots in it in the morning. A-ha! There are! Confirmed! According to geocentrism, the Sun will rise in the East in the morning as it orbits the Earth. A-ha! It did! Confirmed! According to Newtonian physics, this ball will travel in this specific arc when I throw it. A-ha! It did! Newtonian physics confirmed! You get the idea…] 400 years ago, Francis Bacon noticed a strange psychological phenomenon, which fostered irrationality; a phenomenon we now call “confirmation bias”. Confirmation Bias: The tendency to seek out, favor, or focus on, only that evidence or information that confirms one’s pre-existing belief (while overlooking or discounting evidence that disconfirms it). Bacon noticed that human beings have a tendency to accept without question those things which conform to their pre-existing beliefs, and either ignore or rigorously scrutinize those things that oppose them. Even worse, we tend to only LOOK FOR or SEEK evidence that confirms what we already believe, and never seek evidence to the contrary, or examine potential objections to what we already believe. He writes, “it is the peculiar and perpetual error of the human intellect to be more moved and excited by affirmatives than by negatives; whereas it ought properly to hold itself indifferently disposed towards both alike. Indeed in the establishment of any true axiom, the negative instance is the more forcible of the two.” [Bacon stressed the importance of falsifiability over 300 years before Karl Popper did!] While this tendency is often helpful—for instance, likely you’d happily accept without question someone’s claim that they saw a squirrel today, but would seriously question someone’s claim that they saw a unicorn today—confirmation bias can sadly infect our more important beliefs too, such as moral, political, or religious beliefs. For instance, Bacon tells a story of someone who, seeing a painting of some believers who had survived a shipwreck, takes this to be a confirmation that God had saved them. A skeptic replies, “But, where is the painting of all the believers who drowned!?” Confirmation bias can have terrible consequences. For example, regarding people: Whenever we think that some person (or group of people) is good, we tend to overlook their wrongdoings. And, when we think that someone (or some group) is bad, we will tend to find only evidence that confirms this. But, then, someone who favors deportation of undocumented immigrants will be pre-disposed to emphasize or remember crime caused by undocumented immigrants, while ignoring or being blind to crime caused by citizens. (Consider also how racism, sexism, hatred of the “other” political party, etc., will also be fed and fueled by confirmation bias.) Regarding moral and political (and philosophical) beliefs, confirmation bias can cause us to be overly critical of, and see no merit in arguments which oppose our own position; and not critical enough toward arguments which support our own positions. 3. The Source of Our Error: So why so much error? Bacon seems to think that the problem goes to our very core. In order for there to be human understanding of the world, that world must first be filtered through the human senses, human experience, human reasoning… And this filter tends to distort the truth. Bacon writes, “the human understanding is like a false mirror, which, receiving rays irregularly, distorts and discolors the nature of things by mingling its own nature with it.” In short, we ALL filter the world through our own minds. And, Bacon points out, the filter of our minds presents FOUR kinds of obstacle to truth (which he calls the Four Idols): (1) Idols of the Tribe – It is in our very human nature to be susceptible to error. We have already discussed confirmation bias, which all humans are prone to. We also have, as humans, a tendency to see order, regularity, or patterns everywhere. (Bacon: “The human understanding is of its own nature prone to suppose the existence of more order and regularity in the world than it finds.”) For instance, the belief that the planetary orbits are perfect circles; or seeing constellations in the stars; or faces on tortillas, toast, and Mars. (2) Idols of the Cave – Error also arises from our individual natures. We each have our own unique temperament, upbringing, education, and so on—and these color the way that we perceive and interpret the world. For instance, a mathematician might see math everywhere. Someone with a “victim mentality” might interpret everything through that lens. As a smaller example, consider the last time you bought a new phone, or shoes, or learned a new word, etc., and then suddenly started noticing it everywhere. [Can you think of other examples?] In short, each of us is stuck inside the “cave” of our own minds; biased owing to: “his own proper and peculiar nature; or to his education and conversation with others; or to the reading of books, and the authority of those whom he esteems and admires; or to the differences of impressions, accordingly as they take place in a mind preoccupied and predisposed or in a mind indifferent and settled; or the like.” [Side note: Here is the cover of Bacon’s New Atlantis (1626), depicting Father Time freeing Truth from the cave of the intellect. The inscription reads, “Time reveals hidden truth.”] (3) Idols of the Marketplace – In the “marketplace” we exchange words and ideas with one another.