Metaphysics is a dark ocean without shores or lighthouse, strewn with many a philosophic wreck.
Immanuel Kant
Metaphysics is really the branch of philosophy that contemplates the questions of existence, being, the origin of the Universe and similar questions. Unfortunately, the term has also been perverted to mean spiritualism, magic and “experiences beyond physics”.
Let us look at the dictionary definition:
- the branch of philosophy that treats of first principles, includes ontology and cosmology, and is intimately connected with epistemology.
- philosophy, especially in its more abstruse branches.
- the underlying theoretical principles of a subject or field of inquiry.
which we adapt from Dictionary.com
Why it is not science
On the face of it metaphysics seem to be very similar to science. Both subjects want to understand the natural world around us.
The big difference is that science is based on empirical evidence. Science is about exploring the world around us and putting our theories to the test by making empirical predictions. A theory is only scientific if it, at least in principle, makes predictions that we can test.
This is very closely related to the scientific method, which serves as a guideline to scientific thinking. Simplified the scientific method is
- Observation: use your experience of the world. Consider some phenomena.
- Theory: make some mathematical theory that explains the said phenomena.
- Prediction: use your mathematical theory to make predictions beyond the initial phenomena.
- Test: you now look for the predicted phenomena. If you don’t find it you go back to step 2.
The above is of course over simplified and idealistic. The point is one has to make clear predictions that can be tested.
Metaphysics fails here
Metaphysics is not constrained in this way. Metaphysical ideas cannot usually be put to the test via empirical evidence. This means they cannot be falsified. Importantly this means that differing positions in metaphysics cannot be supported or refuted based on experimental evidence.
Therefore, metaphysics requires some belief. You can argue a metaphysical position based on your opinion and maybe some philosophical consequences of this position. However, you could never appeal to experimental or observational evidence. If you could, it would be science!
The lesson for us all
So, when people make claims that they have a theory of everything or a theory of the atom based on high school mathematics or any thing similar you must ask yourself “is it science?”
By this I mean they should have a mathematical framework in which one can make calculations of physical phenomena that can, at least in principle be tested.
If this is not the case then at best it is metaphysics, at worse pseudoscience.
When he to whom one speaks does not understand, and he who speaks himself does not understand, that is metaphysics.
Voltaire
What you say classicly is true, But there are few problems. first, you can come up with another theory that reproduces the old one which does not make a new prediction only the old ones usually to clarify some issues and make the physics less of a mental gymnastics, like Bohm theory and others. Second, Quantum Gravity theories deal with inaccessable energies for experimantation, so the only thing we can rely on is the mathematical consistancy and derivation of the semi-classical(GR) results. Third, As you can see, The physics of the small is inherently very difficult to test (i.e. Brian Cox sagan, FTL …) and there are so many disagreements even among experts on many issues that creates an environment for speculation. The process of weeding out the false and enforcing the right views is messy by nature.
The plural of “anecdote” is not “data,” and data are not information. A good idea need only be testable. It is believable afterward. OTOH, a stupid man alters what a clever man says into nonsense he can understand. Redirected stupidity is not intelligence, whatever its talents for presentation.
http://blogs.discovermagazine.com/badastronomy/files/2011/12/atlas_higgs_plot.gif
3.8 sigma above theory, 1.6 sigma above noise, and the unparticle at 114 GeV does not count.
@qsa:
That is fine. There maybe different theories that agree with each other and nature to accepted degrees of accuracy.
But these should make predictions that are in principle testable. It maybe the case that current technology is not suitable for this. It is likely that one would not see any “residue” from quantum gravity unless we are examining extreme gravitational fields, say near black holes or neutron stars.
Again, see the above remark.
Absolutely true. However understanding is something is really physics or metaphysics is much easier in general.
@Uncle Al:
It can still be a bad idea, but if it is testable then it is science.
I will start by assuming you equate metaphysics with crackpots. The problem is in the gray area with many reputable scientists have been accused of crack poterry. Even Lubosh accused LQG of that, and I am sure a lot of reputable scientist feel that about string but don’t say it outloud for fear of authority. I am just saying the situation is not so simple in the gray areas. There are also many good scientists like Gibbs and Tegmark who support fringe science as you well know. vixra, fqxi ..
But of course there are lots of theories( lets say ideas) with no or very little basis, they are mostly mental exercise. I used to do them when I was younger. They should be left as that.
@qsa:
No, I take metaphysics to be philosophy. However, crackpots often do not know the difference. I also think those that equate metaphysics with mysticism and so on are not doing metaphysics any service.
Metaphysics and philosophy in general can be useful but are in my opinion no substitute for real science.
Sure, things are not always very simple.
And what about a theory which predicts something mathematically,but we can not test it physically with our present technology?
@vedprakash: If something can in principle be tested then it is science. It may well be the case that the technology is lacking. For example, we are only now really able to probe nature for the Higgs. Direct detection of gravitational waves seems just out of our reach. Supersymmetry may also now start to be probed at CERN.
The key thing is that that quite clear predictions need to be made.