the causes of what they observe. 2 HOW WE EXPLAIN THINGSRead more at location 313
Desks and trees, stars and galaxies, atoms and electrons, animals and human beings are all substances.Read more at location 315
Substances have properties: they are square or have such and such a mass or electric charge; and they have relations to other substances:Read more at location 317
Events are caused by substances. The dynamite caused the explosion, one billiard ball caused another to move away, and the marksman caused the motion of the gun trigger.Read more at location 321
Human beings have always sought the true explanations of all the eventsRead more at location 324
and the reasons why those causes had the effects they did.Read more at location 326
We find two different kinds of explanations of events, two different ways in which objects cause events. There is inanimate causation, and there is intentional causation.Read more at location 330
Here we have two kinds of explanation. The first, in terms of powers and liabilities, is inanimate explanation. The second, in terms of powers, beliefs, and purposes, is intentional,Read more at location 335
The second, in terms of powers, beliefs, and purposes, is intentional, or—as I shall call it in future—personal explanation.Read more at location 336
act intentionally), and some events are brought about by inanimate things.Read more at location 339
Some thinkers have claimed that persons and their purposes really make no difference to what happens; brain events cause and are caused by other nerve events and bring about bodily movements without persons and purposes making any difference. But no one can think consistently in that way. To form a purpose (in the sense which I have described) to move one’s hand or whatever involves trying to move the hand.Read more at location 340
These generalizations about when things exercise their powers are called laws of nature, or natural laws, or scientific laws.Read more at location 348
I shall find it more convenient for much of the rest of this chapter to summarize inanimate explanation simply as initial conditions plus law of nature causing event.Read more at location 366
Laws of nature may be universal ones (e.g. ‘all particles of light travel with a velocity of 300,000 km/sec.’) or statistical ones (‘all atoms of radium have a probability of ½ of decaying within 1,620 years’).Read more at location 374
So much for the elements involved in explanation of the two kinds: inanimate substances, and their powers, liabilities, and events which trigger them off; persons, and their powers, purposes, and beliefs.Read more at location 385
A claim that some proposed law is really a law of nature, is justified (i.e. likely to be true, rendered probable) to the extent to which: (1) it leads us to expect (with accuracy) many and varied events which we observe (and we do not observe any events whose non-occurrence it leads us to expect), (2) what is proposed is simple, (3) it fits well with our background knowledge, (4) we would not otherwise expect to find these events (e.g. there is no rival law which leads us to expect these events which satisfies criteria (1–3) as well as does our proposed law).Read more at location 390
Newton’s three laws of motion and his law of gravitational attraction are simple (criterion 2)—in comparison with wild alternatives which could be constructed.Read more at location 433
The ‘simplicity’ of a scientific theory is a matter of it having few component laws, each of which relates few variables by mathematically simple formulaeRead more at location 464
If a theory postulates objects or properties beyond those which we can observe (such as atoms and electrons, quarks or quasars), the criterion of simplicity tells us to postulate few new objects, few new kinds of objects, few new properties, and few new kinds of property—and the fewer the better.Read more at location 466
The rule that you should postulate no more new objects than you need to explain your observations is often called ‘Ockham’s razor’. But how you apply it depends on what you understand by ‘need’.Read more at location 468
The simplest theory for some area which satisfies criterion 1 may not be very simple, but it may still be far simpler than an infinite number of possible theories which satisfy criterion 1 equally well.Read more at location 472
Those who think otherwise say that theories can always be constructed to fit observations, whereas theories do not always predict accurately;Read more at location 493
An example to illustrate the irrelevance to theory-support of when the observations are made is provided by Newton’s theory of motion. This was judged by many (surely correctly) to be highly probable on the evidence available to scientists of the early eighteenth century, even though it made no predictionsRead more at location 496
have made this point at a little length because it is often claimed that theism and fuller theological theories do not make ‘predictions’ which can readily be tested. (They may make predictions about life after death, for example, but those cannot readily be tested now.)Read more at location 502
The same four criteria are at work in judging the worth of personal explanations. In explaining some phenomena as caused by persons, we seek a hypothesis which leads us to expect the phenomena which we would not otherwise expect to find, as simple a hypothesis as possible, and one which fits in with background knowledge.Read more at location 527
The four criteria are at work to determine which of all our many claims about the world beyond observation are most likely to be true. In all fields we seek the simplest hypothesis which leads us to expect the phenomena we find (and which, if there is background knowledge, fits best with it).Read more at location 551
