Addition of adjustments to a theory to save it from being
falsified by compensating for anomalies not anticipated by the
theory in its unmodified form. Theories that rely on continual,
ad hoc adjustments are distrusted.

Statistics: In → significance testing,
any hypothesis which differs from the one being tested. A
hypothesis alternative to the → null hypothesis
is denoted by H_{1}.

The suggestion by Louis de Broglie in 1924 whereby if
→ electromagnetic waves possess particle
properties (→ particle nature),
then it might be reasonable to suppose that material particles, such as
→ electrons, should possess wave properties
(→ wave nature). The
de Broglie hypothesis was based on
the intuitive feeling that nature seems to have strong attachment to symmetry.
In other words,
if radiation has particle-like properties, then material particles should possess wave-like
properties. At the time no direct experimental evidence was present for the validity
of this suggestion.
The first confirmation of de Broglie's hypothesis was provided by the
→ Davisson-Germer experiment. See also
→ wave-particle duality;

Hypothesis,
from M.Fr. hypothèse, from L.L. hypothesis, from Gk. hypothesis
"base, basis of an argument, supposition," literally "a placing under," from
→ hypo- "under" + thesis "a placing, proposition,"
from root of tithenai "to place, put, set," didomi
"I give;"
from PIE base *dhe- "to put, to do;" cf.
Mod.Pers. dâdan "to give,"
Mid.Pers. dâdan "to give," O.Pers./Av. dā- "to give, grant, yield,"
dadāiti "he gives;" Skt. dadáti "he gives;"
L. dare "to give, offer," facere "to do, to make;"
Rus. delat' "to do;" O.H.G. tuon, Ger. tun,
O.E. don "to do."

Engâré, from engâridan, engâštan
"to → suppose." Upâdâyan, from upâ-, → hypo-, +
dâyan, → thesis.

The hypothesis of the origin of the solar system proposed first by Kant
(1755) and later by Laplace (1796). According to this hypothesis, the solar system
began as a nebula of tenuous gas. Particles collided and gradually, under the influence
of gravitation, the condensing gas took the form of a disk. Larger bodies formed,
moving in circular orbits around the central condensation (the Sun).

Named after the German prominent philosopher Immanuel Kant (1724-1804) and the French great
mathematician, physicist, and astronomer Pierre-Simon Marquis de Laplace (1749-1827);
→ hypothesis.

large number hypothesis

انگارهی ِ عددهای ِ بزرگ

engâre-ye adadhâ-ye bozorg

Fr.: hypothèse des grands nombres

The idea whereby the coincidence of various → large numbers
would bear a profound sense as to the nature of physical laws and the Universe.
Dirac suggested that the coincidence seen among various large numbers of different
nature is not accidental but must point to a
hitherto unknown theory linking the quantum mechanical origin
of the Universe to the various cosmological parameters.
As a consequence, some of the → fundamental constants
cannot remain unchanged for ever. According to Dirac's hypothesis, atomic parameters
cannot change with time and hence the → gravitational constant
should vary inversely with time (G∝ 1/t).
Dirac, P. A. M., 1937, Nature 139, 323; 1938, Proc. R. Soc. A165, 199.

The hypothesis first put forward in the 18-th century
that the solar system formed from a primeval nebula around the Sun.
Same as the → Kant-Laplace hypothesis.

Fr.: l'hypothèse de l'Univers sans limite initiale

The proposal whereby the → Universe would not have begun
with a → singularity. Instead, the → Big Bang
would be an ordinary point of → space-time.
The proposal, advanced by James Hartle and Stephen Hawking (1983) results from an
attempt to combine aspects of → general relativity
and → quantum mechanics. Based on an imaginary time
assumption, it predicts a closed Universe that would start at a single point,
that can be compared to the North Pole of the Earth on a two-dimensional space.
Before the → Planck era there was space, but
the real time began with the Big Bang event.
→ Hartle-Hawking initial state.

Statistics: The assumption of the absence of a particular pattern in
a set of data. The null hypothesis, denoted by H_{0}, is
put forward to be rejected in order to support an
→ alternative hypothesis.

An assumed statement about the way a → random variable
is distributed. A statistical hypothesis generally specifies the form of
the → probability distribution or the values of the
parameters of the distribution.
The statement may be true or false. See also → null hypothesis.