Ratio Christi
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Roadmap
Background/Assumptions
Math preliminary
Claim 1: Women’s testimony (W)
Claim 2: Disciples’ testimony(D)
Claim 3: Paul’s conversion (C)
Cumulative case
● “The issue on which everything hangs is not whether
or not you like [Jesus’s] teaching but whether or not
he rose from the dead.” -Timothy Keller
● If true, then Jesus has some insight into an unknown
realm of the universe: life after death
● Reliability of Synoptic Gospels + Acts
Early sources, eyewitness accounts, archeological
support
o Supported by majority of New Testament scholars
(+non-Chrisitian)
o
● Death of Jesus of Nazareth via Roman Cruxifiction
ca. 30CE
● Bayes theorem is useful for historical analysis
● The probability of a claim with some evidence in mind
is how well our claim explains the evidence times the
initial likelihood of the theory, normalized to the
evidence
●
𝑇ℎ𝑒𝑜𝑟𝑦 𝑤𝑖𝑡ℎ 𝑒𝑣𝑖𝑑𝑒𝑛𝑐𝑒 =
● P TE =
𝑃
𝐸𝑇
𝑃(𝑇)
𝑃(𝐸)
𝑇ℎ𝑒𝑜𝑟𝑦 𝑐𝑒𝑟𝑡𝑎𝑖𝑛𝑡𝑦 ∗𝑇ℎ𝑒𝑜𝑟𝑦 𝑒𝑥𝑝𝑙𝑎𝑖𝑛𝑠 𝑒𝑣𝑖𝑑𝑒𝑛𝑐𝑒
𝐸𝑣𝑖𝑑𝑒𝑛𝑐𝑒 𝐹𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦
● Ratio between competing models
●
𝑇ℎ𝑒𝑜𝑟𝑦 𝑤𝑖𝑡ℎ 𝑒𝑣𝑖𝑑𝑒𝑛𝑐𝑒
~𝑇ℎ𝑒𝑜𝑟𝑦 𝑤/ 𝑒𝑣𝑖𝑑𝑒𝑛𝑐𝑒
𝑃
●
𝑃(𝑇|𝐸)
𝑃(~𝑇|𝐸)
=
𝐸𝑇
=
𝑇ℎ𝑒𝑜𝑟𝑦𝑐𝑒𝑟𝑡𝑎𝑖𝑛𝑡𝑦 ∗𝑇ℎ𝑒𝑜𝑟𝑦 𝑒𝑥𝑝𝑙𝑎𝑖𝑛𝑠 𝑒𝑣𝑖𝑑𝑒𝑛𝑐𝑒
𝑇ℎ𝑒𝑜𝑟𝑦 𝑢𝑛𝑐𝑒𝑟𝑡𝑎𝑖𝑛𝑡𝑦 ∗"𝑂𝑡ℎ𝑒𝑟" 𝑒𝑥𝑝𝑙𝑎𝑖𝑛𝑠 𝑒𝑣𝑖𝑑𝑒𝑛𝑐𝑒
𝑃(𝑇)
𝑃(𝐸)
𝑃
𝐸 ~𝑇
𝑃(𝐸)
𝑃(~𝑇)
=
𝑃(𝑇) 𝑃 𝐸 𝑇
𝑃(~𝑇) 𝑃(𝐸|~𝑇)
Bayes
Factor
<1
Likelihood
Reversed
1 − 105
105 -1010
1010 -1015
1015 - 1020
> 1020
Barely
Mentionable
Substantial
Strong
Very Strong
Decisive
Hume Of Miracles (1787)- “I weigh the one miracle
against the other; and according to the superiority,
which I discover, I pronounce my decision, and always
reject the greater miracle. If the falsehood of the
testimony would be more miraculous, than the event
which [the witness] relates” [sic] (I.13)
● T = R = “Jesus of Nazareth was resurrected from the
dead”
● E:
o
o
o
W = Women’s Testimony
D = Disciples’ Testimony
C = Paul’s Conversion
● Cumulative case: multiply Bayes factors (maybe…)
● Evidence: W = “5 women claim to have discovered
Jesus’s empty tomb”
● Luke 24: 1-3, 8-9
● Alternative Explanations [ 𝑃 𝑊 ~𝑅 ]
o
o
o
o
Fabrication
Wrong Tomb
Hallucination
Joseph of Arimathea moved the body
● Considerations
o
o
Multiple attestations
Wild/speculative alternatives
● Bayes Factor:
𝑃
𝑊𝑅
𝑃(𝑊|~𝑅)
● Evidence: D = “13 disciples were willing to die for their
(empirical) claims of R”
o
13 = 12 original - Judas + Matthias + James (Justus)
● Acts 4:18-20
● Alternative Explanations [ 𝑃 𝐷 ~𝑅 ]
o
o
o
o
Fabrication
Zealotry (c.f. Kamikazes or Jonestown)
Hallucinations
Disciples stole the body
● Considerations
● Persevered in attesting to empirical claims
● Alternatives fail to incorporate all members
● Bayes Factor
o
Independence (multiply carefully)



Does R unify testimonies more than ~R?
Other disciples’ deaths
Encouragement in (known) deception?
● Evidence: C = “Conversion of Saul of Tarsus”
● Galatians 1:13-16a, Philipians 3:5-6
● Alternative explanations [ 𝑃 𝐶 ~𝑅 ]
o
o
Hallucination
Fabrication
● Considerations
o
o
Total reversal
Apparent failure of alternatives
● Bayes Factor:
𝑃
𝐶𝑅
𝑃(𝐶|~𝑅)
𝑃(𝑅)
𝑃(~𝑅)
● Initial bias
● Consider other evidential claims
● Cosmological, Fine-tuning, etc.
● Potentially philosophical or ‘off the cuff’
● Dynamic premises
● Full Bayes Factor:
o
o
Independence?
𝑃 𝑅𝐸
= prior* cumulative Bayes factor
𝑃(~𝑅|𝐸)
Bayes
Factor
<1
Likelihood
Reversed
1 − 105
105 -1010
1010 -1015
1015 - 1020
> 1020
Barely
Mentionable
Substantial
Strong
Very Strong
Decisive
● Rapid spread of new worldview and religion (against
authorities, c.f. Jewish and Greco-Roman beliefs)
● Making wild claims (negative evidence) (actually
helps the factor; if substantiated)
● Other well-attested historical facts
●
●
●
●
Alternative explanations for W,D,P?
Negative Evidence?
Valid assumptions? What effect if they don’t hold?
Dwindling probabilities?
 Hume’s paper:
[http://www.bartleby.com/37/3/14.html]
 Bayes factors table [H. Jeffreys (1961). The Theory
of Probability]
 W: Accepted by 75% of NT scholars [Habermas 2006a]
 D: Accepted by majority of scholars [Habermas 2005;
2006a; 2006b]
 P: Integral to the early church
● Alternative Explanations [ 𝑃 𝑊 ~𝑅 ]
o
Fabrication


o
Testimony of women disregarded [cf Luke 24:11]
Incapable of deceiving such a multitude (culturally)
Wrong Tomb





Unlikely that multiple women would lose the tomb
Disciples lost tomb too?
Authorities didn’t produce the body
Doesn’t account for claims of seeing Jesus
Group conformity? (Asch experiment)
● Alternative Explanations [ 𝑃 𝑊 ~𝑅 ]
o
Hallucination


o
5+ women hallucinating same thing is prohibitively
miraculous (see discussion for D)
(Group) hallucinations require emotional excitement,
expectation and suggestion
Joseph of Arimathea moved the body



Ad hoc acceptance of Gospels’ claims
Contradicts rabbinic teaching
Joseph didn’t speak against Christians
● Alternative Explanations [ 𝑃 𝐷 ~𝑅 ]
o
Fabrication



o
Unaccounted transformation: timidity to boldness
Falls apart in the face of persecution (cf witness
intimidation)
Motive?
Zealotism (cf Kamikazes or Nazis)



Converts vs Believers
Empirical claims vs Ideologies
Diminishes with persecution
● Alternative Explanations [ 𝑃 𝐷 ~𝑅 ]
o
Hallucinations



o
(Group) hallucinations require emotional excitement,
expectation and suggestion
Parallel, integrated and detailed
Suddenly ceased
Disciples stole body


Continued devotion unlikely
Doesn’t explain claims of interaction (not just missing
body)
● Alternative explanations [ 𝑃 𝑃 ~𝑅 ]
o
Hallucination


o
Utterly unprecedented (cf previous discussions)
Persecutor to Pastor?
Fabrication


Committed Jew
Witnessed persecution