Scientific Deduction, Induction and Hypothesis

[Progenitor A]

Lovely discussion yesterday on Melvyn Braggs show
It showed that science is based on (very unreliable) induction
Induction is the process of generalising from particulars, where the premise and corollary cannot be shown to be true

An hypothesis (as I have insisted many times - when enthusiastic atheists have demanded proof for the God hypothesis)) does not need 'proof'; if proof is forthcoming it ceases to be an hypothesis

Deduction is far more reliable than induction. In deduction a corollary is always true if the premise is true. Thus deduction is not suited to the hcientific method.
Many people think, for example that the 2nd law of thermodynamics is deducable - it is not it mere induction, speculation

Popper recognised this and demanded that we should look to falsify hypothses reather than prove them for proof can never be obtained

This led amusingly to Poppers psuedo-science. where hypotheses are framed such that a scientific corollary always is true if the premise is true. Thus psuedo-science (as Melvyn wittily observed) is false science because it is true
An example?
God created the world therefore we are creatures of God.
QED
;D

[marchesarosa]

I missed that. I do enjoy Bragg's discussions.

There is a lot of discussion of thermodynamics in the climate debate, nay. I don't understand it, of course. But some people claim the greenhouse gas hypothesis of "back-radiation" warming the surface contradicts the 2nd Law. Others are now arguing that gravity in the form of differential air pressure is enough to account for the warmer temperature at ground level than on high.

Fascinating!

According to the alarmists quite a lot of sceptics are seriously misunderstanding thermodynamics, whereas sceptics are arguing that we are on the verge of a breakthrough into a new understanding of atmospheric physics.

Who knows! It would be great if something really useful came out of the AGW controversy - something that changed our understanding of the world.

[robinpike]

It's not even that clear cut, for any statement about the physical world can neither be proved nor disproved (including this hypothesis).

Every statement about the physical world is an interpretation of facts, but even the facts themselves are interpretations of something.

What happens is that for most statements we reach the position where the statement is far more likely to be true than false (or vice versa), and so becomes accepted as true / false.

[Progenitor A]

Jan 27, 2012 14:55:52 GMT 1 robinpike said:

It's not even that clear cut, for any statement about the physical world can neither be proved nor disproved

??
Not any statement can be disproved?
Here's one for starters

The moon is made of green cheese

[mak2]

What this proves, is that Melvyn Bragg does not understand science.

But what can you expect from an Oxford history graduate?

[robinpike]

"The moon is made of green cheese".

That statement has three elements to it: the moon, the colour green and cheese.

Taking the basic consequence of the statement: that we know what the moon is made of: how can that be known without there being some possibility of doubt?

[Progenitor A]

Jan 27, 2012 15:47:59 GMT 1 mak2 said:

What this proves, is that Melvyn Bragg does not understand science.

But what can you expect from an Oxford history graduate?

?
He was not speaking to himself bur to 3 distinguihed science philosophers. I may have misquoted them, but you haven't bothered saying whay is wrong

[Progenitor A]

Jan 27, 2012 15:56:48 GMT 1 robinpike said:

"The moon is made of green cheese".

That statement has three elements to it: the moon, the colour green and cheese.

Taking the basic consequence of the statement: that we know what the moon is made of: how can that be known without there being some possibility of doubt?

It matters not that what we know of the moons constitution cannot be known with certainty (although it is!), but it matters simply that it can be demonstrated (and it has) that it is not made of green cheese
Surely?

[robinpike]

The example statement "the moon is made of green cheese" is very likely to be false, but it cannot be proved as false or true.

For example, a mission to the moon brings back some moon rock for analysis here on earth. How do you know that an advanced alien civilisation living on the moon that wants to keep the 'green cheese' content of the moon a secret, has not performed mind control on the astronauts into thinking that they landed on a rocky moon, and then on their return substituted, the green cheese samples with rock samples?

[robinpike]

"The moon is made of green cheese" is perhaps a poor example to argue this point about.

Let's take some that are of more scientific relevance:

i) The inability to measure a change in our movement to any change in the velocity of light, has led to Relativity and the statement that there is no universal frame of reference.

ii) The behaviour of light and electrons in the two slit experiment has led to the statement that light and sub-atomic particles have an uncertainty to their position in space.

Neither of the above conclusions can be proved as being certainly true.

[Progenitor A]

Jan 27, 2012 17:10:45 GMT 1 robinpike said:

The example statement "the moon is made of green cheese" is very likely to be false, but it cannot be proved as false or true.

For example, a mission to the moon brings back some moon rock for analysis here on earth. How do you know that an advanced alien civilisation living on the moon that wants to keep the 'green cheese' content of the moon a secret, has not performed mind control on the astronauts into thinking that they landed on a rocky moon, and then on their return substituted, the green cheese samples with rock samples?

I see your point
However, I always favour a little Occan sense when dealing with such matters, rather than making statements such as:
It has been established by direct measurement that the moon's material constitution is not of green cheese, with the caveat that an advanced alien civilisation living on the moon that wants to keep the 'green cheese' content of the moon a secret, has not performed mind control on the astronauts performing the measurement, and indeed the scientists that examined returned specimans into thinking that they landed on a rocky moon, and then on their return substituted, the green cheese samples with rock samples

The sentence is too long and includes only one possibility, and there is also the possibility (approaching a probability of unity)that the alternative possibility cannot, in principle, be determined and hence is not a scientific proposition, whereas the proposition that the moon is not green cheese is confuted by the lumps of rock, which most certainly are, if only subjectively, lumps of rock when the measurement was observed

[Progenitor A]

Jan 27, 2012 17:39:26 GMT 1 robinpike said:

"The moon is made of green cheese" is perhaps a poor example to argue this point about.

Let's take some that are of more scientific relevance:

i) The inability to measure a change in our movement to any change in the velocity of light, has led to Relativity and the statement that there is no universal frame of reference.

ii) The behaviour of light and electrons in the two slit experiment has led to the statement that light and sub-atomic particles have an uncertainty to their position in space.

Neither of the above conclusions can be proved as being certainly true.

I agree that these cannot be shown to be true, but please do remember that we are attempting to show the falsity of scientific statements - something that you maintain is not possible

Here is another statement that can easily be shown to be false

The force of gravity repels two bodies in proportion to their mass and in inverse proportion to their separation

[robinpike]

"Two bodies repel each other in proportion to their mass and in inverse proportion to their separation"

You would think that the above statement must be false, but consider the possibility where the above is true but in addition there is a second force, and the two forces combined causes two bodies to attract each other in proportion to their mass and in inverse proportion to their separation.

Note that for clarity of this point, I removed the term 'gravity', as this isn't about contradicting the meaning of the word 'gravity'.

[Progenitor A]

Jan 27, 2012 18:09:49 GMT 1 robinpike said:

"Two bodies repel each other in proportion to their mass and in inverse proportion to their separation"

You would think that the above statement must be false, but consider the possibility where the above is true but in addition there is a second force, and the two forces combined causes two bodies to attract each other in proportion to their mass and in inverse proportion to their separation.

Note that for clarity of this point, I removed the term 'gravity', as this isn't about contradicting the meaning of the word 'gravity'.

Ah but it does not matter that there may be occasions when it is true - just one occasion when it is false is enough to establish the falsity of the statement

[robinpike]

The point is that when we do an experiment, it consists of all sorts of assumptions.

Yes, our understanding of experiments at the macro level are almost certainly correct, for if not, then there would have to be some fantastic alternative explanation (such as this is all a dream, etc).

But when it comes to what is happening at the micro level, the point about not being able to prove or disprove statements becomes very relevant.