On
conclusive presumptions

Classes of Conclusive Presumptions
1. Estoppel in Pais
   whenever a party has, by his own declaration, act, or omission,
   intentionally and deliberately lead another to believe a particular
   thing to be true and act upon such belief, he cannot, in any
   litigation arising out of such declaration, act or omission, be
   permitted to falsify it.

2. Estoppel by Deeds
   the tenant is not permitted to deny title of his landlord at the
   time of the commencement of the land-lord tenant relationship. If
   the title asserted is one that is alleged to have been acquired
   subsequent to the commencement of that relation, the presumption
   will not apply.


Presumption
An inference as to the existence or non-existence of a fact which
courts are permitted to draw from the proof of other facts.

A presumption shifts the burden of going forward with the evidence.
It imposes on the party against whom it is directed the burden of
going forward with evidence to meet or rebut the presumption.