When the objects of an inquiry, in any department, have principles, con-
ditions, or elements, it is through acquaintance with these that
knowledge, that is to say scientific knowledge, is attained. For we do not
think that we know a thing until we are acquainted with its primary con-
ditions or first principles, and have carried our analysis as far as its sim-
plest elements. Aristotle, Physics, bk. 1, ch. 1.
If a thing can be done adequately by means of one, it is superfluous to
do it by means of several. Thomas Aquinas [7, p. 129]
It is vain to do with more what can be done with fewer. William of Ock-
ham, as quoted in Russell [8, p. 472]
We are to admit no more causes of natural things than such as are both
true and sufficient to explain their appearances. To this purpose the phi-
losophers say that Nature does nothing in vain, and more is in vain when
less will serve; for Nature is pleased with simplicity, and affects not the
pomp of superfluous causes. Isaac Newton [9, bk. 3, Rule I]
…if everything in some science can be interpreted without assuming this
or that hypothetical entity, there is no ground for assuming it. Russell [8,
In scientific thought we adopt the simplest theory which will explain all
the facts under consideration and enable us to predict new facts of the
same kind. J.B.S Halldane, Science and Theology as Art-Forms, 1927.
As quoted in McAllister [10, p. 105]
It can scarcely be denied that the supreme goal of all theory is to make
the irreducible basic elements as simple and as few as possible without
having to surrender the adequate representation of a single datum of ex-
perience. Einstein [11, p. 165]
…different, conflicting theories are consistent with the data; ...Given
that the theories differ precisely in what they say about the unobserva-
ble... a challenge to realism emerges: the choice of which theory to be-
lieve is underdetermined by the data. Chakravartty 
If one considers the history ...what one typically finds is a regular turn-
over of older theories in favour of newer ones, as scientific knowledge
develops. From the point of view of the present, most past theories must
be considered false; indeed, this will be true from the point of view of
most times. Therefore, ... surely theories at any given time will ulti-
mately be replaced and regarded as false from some future perspective.
Thus, current theories are also false. Chakravartty 
(a) The Relativity Principle was postulated in Special Relativity.
(b) Special Relativity was extended into General Relativity.
(c) General Relativity was extended into FLRW.
(d) The Relativity Principle contradicts absolute simultaneity.
(e) Cosmology requires cosmic time which requires absolute simultaneity
and thus contradicts the Relativity Principle.
(f) Escaping the contradiction requires either rejecting the Relativity Princi-
ple or rejecting cosmic time.
(g) Neither can be done. Rejecting the Relativity Principle would mean
breaking the backbone of GR and thus also FLRW. Rejecting cosmic
time would render FLRW useless.
(a) The Relativity Principle entails eternalism.
(b) Eternalism leaves the direction of time open.
(c) Therefore GR needs an anchor for the direction of time.
(d) Entropy is now the commonly accepted anchor.
(e) Entropy that is applicable as the anchor is that of total entropy of a TSU).
(f) The concept of total entropy of a TSU whose parts exist simultaneously,
entails absolute simultaneity.
(g) Total entropy thus contradicts the Relativity Principle.
(h) Therefore, entropy cannot function as an intelligible anchor for the direc-
tion of time in the context of GR.
The weaknesses of a theory often do not appear if the theory confronted
with the facts as seen from its own perspective, but may only appear if
facts as seen from the perspective of an alternative theory are allowed.
Hoyningen-Huene [64, p. 10]
1 For congenial formulations, see Quine [1, p. 11] and Cameron [2, p. 250].
2 Economy has also been called Ockham’s razor and the principle of parsi-
3 The weight of metaphysical commitments of a theory is determined by the
number of different types (or kinds) of metaphysical entities, and quantities
of each type. Both the number of kinds of entities and the quantity of entities
of each kind need to be counted, for one can compensate the other (cf. Nolan
4 According to Sider [31, p. 230], Quine’s  ideological commitments are “as
much commitments to metaphysics as are ontological commitments.”
5 E.g. Planck [16, pp. 33-4] and Feyerabend [17, pp. 193-4]  warn about
the dangers of dogmatism. See also Narlikar, this volume.
6 Aliseda and Gilles [21, pp. 466-7] propose “that philosophers of science have
to develop not only a theory of the growth of science, but also a theory of the
appraisal of scientific hypotheses. ...we need a theory of the appraisal of sci-
entific hypotheses which does not involve detailed considerations of how
those hypotheses are discovered.” Economy is a suggestion of exactly this
kind of a ‘theory’ or a criterion of fitness.
7 Niiniluoto (personal communication, 21.5.2016) confirms that he accepts the
idea that the similarity approach is first applied in picking out theories with
the most accurate predictions, and after this the aesthetic features such as sim-
plicity are evaluated.
8 These remarks conform to Snyder  and Whewell [33, pp. 83-96].
9 For the basic structure of DU, see Suntola  and this volume, and Suntola
et al. . See Suntola [36, p. 125] for comparison of the postulates.
10 This test is analogous to Chou et al. , where the difference in heights of
the clocks was less than 1 meter, and the resulting difference in their velocities
less than 10 meters per second.
11 See Suntola [38, pp. 12, 55-7, 283-4, 301, 313] and this volume, §4.
12 As in this test we are dealing with differences in the state of gravitation,
Schwarzschildian metrics is applied. If we were dealing only with differences
in velocity in a fixed state of gravitation, Lorentz transformations would suf-
13 See Suntola [38, pp. 36-9, 73-4] and this volume, §4.
14 Lehti  notes that Einstein [41, pp. 98-9] in no way indicates that he has
given a suggestion about the structure of the Universe which is incompatible
with his own Relativity Principle.
15 See e.g. Rietdijk , Putnam , Peterson and Silberstein  and Saun-
ders  for proofs. The fusion of eternalism and partial determinism —or
indeterminism— implies some version of branching space-time (Belnap
). If branching space-time is evaded by selecting total determinism —also
called causal determinism— the question boils down to whether total deter-
minism is plausible after all, as it is e.g. incompatible with free will.
16 This definition is congenial with e.g. Dummett [49, p. 73-4] and Putnam [44,
17 See e.g. Broad [50, pp. 59-60] and Deasy [51, p. 2075].
18 See Sider [52, p. 261]. Merricks’ [53, p. 105] critique of the growing-block
theory applies also to the moving spotlight theory.
19 See Suntola [38, §§1.2.5, 3.3.1, pp. 254-6], [36, pp 186-7], this volume, §4.
20 The following was inspired by Sipilä .
21 The standard interpretation since the 1930’s has been that galaxies and plan-
etary systems do not expand but the Universe as a whole expands (de Sitter
). The expansion is explained by Hubble flow between galaxies or galaxy
groups (de Sitter ).
22 See e.g. Gough  and Bahcall et al. .
23 Emiliani [61, p. 543] notes that there was water in Mars more than 3 billion
24 See e.g. Kusky [62, p. 238] and Le Bihan and Fukuyama [63, p. 344]. In terms
of DU, ‘3.85 billion years ago’ is translated as ‘when the 4-radius of the Uni-
verse was 3.85 billion light years smaller’.
25 Lunine [65, p. 162] notes that the Earth should have been frozen for the first
three billion years due to the faint Sun but that geological findings suggest
that the temperature of the seas was much higher 3.4 billion years ago than
26 See Suntola, [38, §§7.3.3, 7.4.2] and this volume §4, for the effect of the ex-
pansion of space on Earth to Moon distance, and the compatibility of DU’s
predicted expansion with coral fossil data.
27 Pierre-Simon Laplace, Mécanique Céleste 1, 1799-1825.
28 See Suntola [36, pp. 175-6] and this volume, §4.