# Last Thursdayism

Last Thursday or Last Thursdayism is a philosophical claim of the reductio ad absurdum type, challenging creationism. According to this claim, the age of the universe does not predate last Thursday. Everything we know about what came before last Thursday is an illusion since, on that day, all evidence of the world's age, including human memories and physical records, was created.
Similar to the "Flying Spaghetti Monster," this idea has evolved into a parody religion.

## Background

Attempts to determine the age of the universe, or the time elapsed since creation, have been made in all religions and ancient cultures. A literal interpretation of the Book of Genesis suggests that the universe is approximately six thousand years old, an idea known as "creationism."
Early scientific attempts to determine the universe's age began in the 19th century and initially focused on determining the age of Earth. Evidence for this was found in the emerging field of geology, which began constructing the geologic time scale based on Earth's strata layers. For example, in 1862, Lord Kelvin estimated Earth's age at 50–150 million years based on the time required for a molten Earth to cool to its current temperature. Such calculations sparked conflict between religious and scientific views, leading to heated debates.
In response to this tension, French writer François-René de Chateaubriand wrote in 1802: "God could have, and undoubtedly did, create the world with all the signs of its antiquity and perfection that it now displays."

### Omphalos hypothesis

In 1857, British naturalist Philip Henry Gosse published "Omphalos" (Greek for "navel"), aiming to "resolve the geological dilemma." Gosse attempted to reconcile the literal interpretation of the creation story in the Bible with the geological evidence of Earth's gradual—and much earlier—formation. The book's title referred to Gosse's hypothesis that Adam and Eve had navels despite not being born, symbolizing their perfect creation. Similarly, trees had growth rings that had never grown, created instantaneously. All fossil evidence of early life, Gosse argued, was a divine fabrication: such life never existed. God created it ex nihilo at the moment of creation.
Gosse's friend, Reverend Charles Kingsley, responded that he could not believe God had "written such a great and unnecessary falsehood upon the rocks for humanity."

### In Judaism

In the Talmud, Rabbi Yehoshua ben Hanania states that the world was created in Nisan, during spring, citing the verse "trees yielding fruit," indicating that trees were created in their fruit-bearing state. The Talmud elaborates:
   Rabbi Yehoshua ben Levi said: All the acts of creation were created in their full stature, with full understanding, and with their full beauty. As it says: "And the heavens and the earth were finished, and all their hosts" – do not read "hosts" but "beauty."
Rabbi Menachem Mendel Schneerson wrote in response to a question about fossils:
   Even if we assume that the time period given by the Torah for the age of the world is too short for the fossilization process (although I do not see how this can be determined with certainty), we can still easily accept the possibility that God created fossils as their mold, bones or skeletons (causes known to Him), just as He could have created living organisms, a complete human being, and finished products such as coal or diamonds, without any evolutionary process.

## History of the argument
### Five-Minute Hypothesis

In 1921, Bertrand Russell proposed the "Five-Minute Hypothesis" to demonstrate the arbitrariness of assigning a young age to the universe.
   There is no logical impossibility in the hypothesis that the world sprang into being five minutes ago, exactly as it then was, with a population that "remembered" a wholly unreal past. There is no logically necessary connection between events at different times; therefore, nothing that is happening now or will happen in the future can disprove the hypothesis that the world began five minutes ago.

### Last Thursday

The "Last Thursday" claim likely originated in the 1990s. In the early 21st century, a "church" of "Last Thursdayism" was established with a parody religion and tenets of faith. The church sparked lively debates online.
Both the Five-Minute Hypothesis and Last Thursdayism use reductio ad absurdum to challenge creationism's assertion that the universe's young age should be accepted due to the impossibility of disproving it. These arguments illustrate the arbitrary nature of religious claims about the universe's age.

## As satire

The claim is presented as a parody religion, a satirical tool. The "Church of Last Thursdayism" website attempted to equate belief in Last Thursdayism with an actual religion, listing "tenets of faith":
   The universe was created on Thursday and will expire on Thursday.
   The universe was created by you as a test for yourself. You will receive reward or punishment based on your actions in this test. Left-handedness is a sinful temptation. Everyone except you was placed here and pre-programmed to act as part of your test environment. Everyone except you knows this.
   The purpose of this one-week test is to discover your moral boundaries and character.