The knowledge of which geometry aims is the knowledge of the eternal. Plato (427-347 BC) A wise man proportions his belief to the evidence. David Hume (1711-1776) If only one person knows the truth, it is still the truth. Mahatma Gandhi (1869-1948) Expliquer le réel par l'impossible. Alexandre Koyré (1892-1964) God exists since mathematics is consistent, and
the Devil exists since we cannot prove it. BourbakistAndré Weil (1906-1998) Physics isn't a religion. If it were, we'd have a much easier time raising money. Leon M. Lederman
(1922-2018, Nobel 1988)
Philosophy is what you have to do until you know what the right questions are. Daniel C. Dennett (1942-)
Morganne (2004-01-29) Scientific Creations
Isn't it true that Art is created and Science discovered?
This is mostly so, but not entirely.
Even for a Platonist like myself, it's difficult to argue that scientific
facts are just sitting there waiting to be discovered by some clever
sleight of hand.
First, a language must be created for those facts
to become expressible. This language is purely a human creation.
Second, a physical law need not be absolutely true to be considered scientific.
For example, Newtonian mechanics considers only objects whose masses are independent
of their speeds, spins and temperatures.
It's now clear (from the many experimental results confirming the quantitative predictions of
Special Relativity) that such things simply do not exist.
Yet, Newtonian mechanics was and remains a superb scientific theory.
It's clearly not the ultimate law of nature, but it would be silly to demand
that Science and scientists suspend all publications until all flaws are resolved.
Scientists must routinely invent and create new concepts like mass, velocity
or entropy.
The meanings of such constructs may evolve and none of them
are strictly necessary to describe physical reality.
They are just clever human creations whose beauty is ultimately revealed
by their ability to organize human thoughts and computations about the World.
An artist may have a lot more creative freedom than a scientist does,
but Science still entails considerable leeway.
At the deepest level,
scientific theories are beautiful carvings which describe
a specific abstract approach to reality, just like most sculptures
capture one aspect of reality for the sole sake of beauty.
In both cases, random chiseling is not permissible;
a lot of skill and channeled creativity is required.
A heap of scattered scientific facts is to
a consistent scientific theory what an uncarved block of marble
is to a polished statue.
Without dreams, there is no art, no mathematics, no life. Sir Michael Atiyah (1929-2019)
(2005-06-20) David Hume (1711-1776)
Skepticism and Empiricism.
Locke, Bekeley, Hume, Newton.
Recovering the power of the senses.
Induction,deduction.
The arrogance of the senses.
(2005-06-20) René Descartes (1596-1650)
Mind and Matter. Free will and the clockwork universe.
Anne Finch Viscountess Conway:
Body, mind and spirit.
(2005-06-20)
Benjamin Franklin (1606-1790)
Intuition: Certainty all at once.
Certainty all at once.
(2011-10-29) Separating Religion from Science
The question of the existence of God is not a scientific one.
Napoléon: Où est Dieu dans tout cela? Laplace: Sire, je n'avais nulle besoin de cette hypothese. Pierre-Simon Laplace (1749-1827)
(2004-03-26) SETI: Listening is not enough.
In the SETI project, we've spent only a few minutes "talking".
What's wrong with that?
We've spent only a tiny amount of time "talking to" possible
extraterrestrial civilisations.
If those have the same attitude, there is no point listening.
The painful conclusion is that we have to spend some unselfish time
talking if listening has any sense at all.
This is true in spite of the fact that we'll never get any feedback.
I argue that morality (in the sense
Immanuel Kant defined it)
is either unselfish or nonexistent.
If we value at all the extraordinary gift it would be to receive
a message from other civilizations, we must extend the same courtesy
by sending them something to listen to.
If we bother listening, we have a moral obligation to talk.
(2004-03-26) The Anthropic principle
The Universe we see must have properties that allow human life.
(2004-03-26) Support Science
What makes a society worth defending... [Bob Wilson about FermiLab]
(2006-08-30) About Mathematics
What's "mathematics", anyway?
No one shall expel us from the paradise which Cantor has created for us. David Hilbert (1862-1943)
A self-destructive democratic principle was advanced in mathematics
(especially by Hilbert),
according to which all axiom systems have equal right to be analyzed,
and the value of a mathematical achievement is determined,
not by its significance and usefulness as in other sciences,
but by its difficulty alone, as in mountaineering. Vladimir Arnold (1937-2010)
Most philosophers have not practiced enough mathematics to grasp
the significance of any nontrivial mathematical endeavor,
let alone put them all in perspective.
Most mathematicians have not practiced enough philosophy to feel any
need to reflect on their own discipline, let alone "define" it.
So, who's to say what mathematics really is?
Well, ... / ...
Mathematics is all about the acquisition of certainty.
Following traditional rules to obtain results does not validate such results;
the rules themselves must be scrutinized "mathematically"
to remove all doubts and allow absolute confidence in whatever results
are ultimately stated.
For example, Distribution theory validates
our intuition about Dirac's delta "function".
If intuitive manipulations of the delta function weren't valid,
ditribution theory shows that other trusted algorithm wouldn't be either.
Results based on the concept of distribution are as
trustworthy as those which involve only elementary arithmetic.
In other words, "time" is defined as the independent variable
which makes the equations of mechanics take on a simple form.
This operational definition was designed in a simpler era of "classical" physics.
It still holds for nonrelativistic quantum theory,
where time remains an old-fashioned independent variable.
However, at a deeper level of understanding, time cannot be simply such an
"independent" parameter against which events are recorded.
Instead, it's a component of spacetime
(to a degree, time and space can be traded for each other).
This has profound implications for our modern descriptions of the physical world.
Especially in the quantum realm.
Time Travel and Perpetual Motion
Time travel is like perpetual motion; it's both unavoidable and impossible.
Let me explain this paradox:
At the microscopic level, time-travel is unavoidable.
Elementary particles routinely go backward in time;
there's no difference between a particle moving forward in time
and its antiparticle moving backward in time.
So, a "particle-antiparticle" pair creation may also be described as a particle
changing the direction of its "time flow".
Now, can this fundamental mechanism be harnessed to make coherent systems
consisting of many particles (and carrying definite information with them) go back in time?
The answer is as much of a "no" as what applies to the related question of
whether it's possible to transform brownian motion into coherent motion
(that would be what's called perpetual motion "of the second kind").
If you don't believe in one, you don't believe in the other...
Of course, science is not supposed to be about beliefs, but it is (to a degree).
It's a much more productive belief (from a scientific standpoint)
to assume that perpetual motion can't exist than the opposite...
In one case, you'll refine the basic laws of thermodynamics.
In the other case, you may waste your life on doomed tinkering.
Similarly, the impossibility of time-travel imposes useful constraints
on the very laws of fundamental physics we are aiming to formulate.
It's almost certainly the more useful of two possible beliefs, to put it in provocative terms.
This does not mean you can't have fun thinking about the paradoxes of time-travel.
However, those very paradoxes should be an indication that
attempts at building an actual time-machine are as doomed as
attempts to build a perpetual motion machine.
Or vice-versa.
