About PredictionX and the Prediction Seminar

Part of what makes us human is our desire to learn our own future.  Throughout recorded history, people have sought ever-more-powerful methods of Prediction.  In ancient times, sheep were sacrificed and priests read signs from the gods in their entrails; revered oracles were consulted; and astrologers read the future in the heavens.   Great scholars began to debate determinism vs. free will–is there a pre-ordained future, or do our own actions affect the future?–and that debate has never really ended.   Today’s arguments over whether human activty or “nature” is responsible for global climate change are still effectively a battle of free will vs. determinism–but our methods for settling the argument have expanded beyond what was available to ancient philosophers.

In both the online HarvardX course called “PredictionX,” and in the “Prediction” Freshman Seminar at Harvard, we trace and analyze the history of Prediction over time.   We begin with Omens, Oracles, Religion & Prophecy, and then,  move on to the so-called Scientific Revolution, exemplified by the work of Galileo, and the Age of Exploration, enabled by John Harrison’s solution to finding longitude at sea. The second half of the courses focuses on predictive work in epidemiology, finance, and climate, and ultimately on work about the Universe’s future. At the end of the courses, we consider and discuss how computer models of health/wealth/climate combine to predict our future. This WordPress site, established in January 2015,  holds student contributions in response to assignments given in the  “Prediction” Freshman Seminar at Harvard, the full name of which is “Harvard Freshman Seminar 27j: Prediction: From Ancient Omens to Modern Computer Simulations, the syllabus for which can be found at the course web site.

About PredictionX and the Prediction Seminar

Cobá and the Mayans

“Small” Pyramid at Cobá

Alyssa Goodman visited the Mayan site of Cobá on February 19, 2015.  The image at left shows the smaller (about 25 m high) of two solid-stone temple pyramids at the site.  The height of the pyramids, according to a “Mayan” tour guide at Cobá, was intended to get the priests closer to the Gods.

The kinds of divination that priests carried at Cobá, which is one of the oldest Mayan sites known (dating from about 100 BC) , included scrying with special mirrors, as described in Sohum’s post, and shown in the image he provided, below.

An example of an ancient Mayan scrying mirror in use. (Source: Healy and Blainey)
An example of an ancient Mayan scrying mirror in use. (Source: Healy and Blainey)

The most interesting prediction-relevant tale our guide told us on our tour of Cobá (which by the way takes place by bicycle), was about Mayan astrology–perhaps their most important form of divination.  In particular he explained that every “century” (actually 102 to 104 years) the Venusian calendar and the Mayan Tzolkin (a system based mostly on lunar months,see below with a 260 day cycle) and the Earth-Sun year (~365 days) coincided so as to “align” the calendars–which was a particularly auspicious event–a time for war.  Read more at http://www.ancient-world-mysteries.com/mayan-aztec-century.html.  Actually, the half-century (or 52 years) is depicted in the stellae at Cobá.  Someday soon, I will attempt to reproduce all this in WorldWide Telescope–unless one of you would like to take on that project?!

Why have you likely not heard of Cobá? Wikipedia correctly surmises that: The site remained little visited due to its remoteness until the first modern road was opened up to Coba in the early 1970s. As a major resort was planned for Cancún, it was realized that clearing and restoring some of the large site could make it an important tourst attraction.  According to our tour guide, only 5% of Cobá’s 40 square miles have been excavated.

Interesting related links:

http://www.maya-portal.net/calendar, including the interactive Tzolkin calculator at http://www.maya-portal.net/tzolkin

Note that the Tzolkin (basic cycle of the Mayan Calendar) was used for Prediction in the following ways:

  • Finding dates are suitable for particular actions. For instance,  a low-numbered Ak’ab’al or B’en would be a good day for a wedding, whereas K’an would be a good day for building or maintaining a house.
  • For divination based on casting lots and counting forward through the calendar from the current ‘year bearer’ to arrive at a day which is then interpreted. This is not pure cleromancy because somatic twitches of “blood lightning” can either be specifically consulted or arise spontaneously during the process.

Scenes from Cobá.

Looking down from near the middle (not the top!) of the tall (48 m) pyramid.
Guide showing a site map.
Guide showing forehead flattening practiced by “the upper class.”
The Mayan world view (cosmology), represented by a tree.
Stellae showing tree of Mayan world view
Watchtower, note wraparound walkways–used to lookout for those coming to town on long, elevated, gleaming stone roads
Actual tree near tree stellae, allegedly same kind of tree depicted.
Ball Court
Cobá and the Mayans

Drawing Lots: When Fate and Chance are the Same

A common divination method for the Ancient Romans was to cast lots, called sortes in Latin, to attempt to figure out the will of the gods. Essentially, this process entailed using randomization as a means to determine the future, and there were various methods to create this randomization. A common method was to create different sortes representing different meanings and either throwing them into or drawing one out of a water filled urn, or situla.

Situla: situla

Another method to create randomization was to throw die and divine some meaning from the results.


Later, the Ancient Romans became a bit more sophisticated in their approach and started drawing random lines of poetry to predict the future, notable from the works of Homer and Vergil. The thinking was that such a line drawn could be interpreted as an omen of the future for the drawer. This practice came to be known as Sortes Homerica and Sortes Virgilianae, for the works of Homer and Vergil, respectively. This approach of taking a random line from a work of literature or poetry eventually became the inspiration for the early Christian practice of Sortes Sanctorum,which involved using lines from the Bible to divine the future. Churchgoers would take the line of Scripture they heard as they entered Church and try to extract special meaning, or in a more formal process, one could open the Bible at random and take the first line he or she read. Thus the ancients merged two concepts — fate and chance — which arguably are antonyms, in divining the future.

Drawing Lots: When Fate and Chance are the Same

Gazing into the future: Ancient Mayan Scrying

Mayan mirror
An example of an ancient Mayan scrying mirror. (Source: Healy and Blainey)

One of the most prominent methods of prediction in the Ancient Mayan world was the use of polished mirrors to gaze into the”Otherworld” and divine the future. Specimens of these mostly circular mirrors, which were made up of fragments of iron ore tiled like a mosaic and mounted on a slate backing, range from c.600 BCE to c.900 CE in origin, suggesting that they played a role in Mayan culture across a broad period of time.

According to literature on the subject, the Mayans attached a mystical importance to reflective substances. Reflective items were often worn or wielded by the upper echelon of Mayan society, and only the most skilled stoneworkers and artisans were chosen to create the specialized iron ore mirrors.

An example of an ancient Mayan scrying mirror in use. (Source: Healy and Blainey)
An example of an ancient Mayan scrying mirror in use. (Source: Healy and Blainey)

Per Mayan lore, the gods, unhappy with human abuse of their full capabilities of sight, reduced what mankind could “see.” However, they granted shamans and kings the role of interpreters: using their specialized mirrors, they could “scry” into the mystical “Otherworld,” and catch glimpses of the future, and the will of the gods. Thus, they gained power from the role they held as conduit between “ordinary people” and the gods.


In response to the prompt on “Ancient Ways.”

Gazing into the future: Ancient Mayan Scrying