Perpetual motion is technically not possible: things don't run by themselves. It violates the law of conservation of energy, which states that "energy can never be created or destroyed, but only conserved".
Technically impossible? Is that different from physically impossible? or actually Impossible? Technolically impossible seems to imply that if technology were to change then something technically impossible may become physically possible and actually possible. Is that not the case that occured when the Wright brothers flew? When we launched into space and put a man on the moon? You can go on to cite many other instances through out history of man where thing thought to be impossible "Technically" became actually possible because they were physically done.
To state it correctly "FREE ENERGY" is impossible, unless you want to open a can of worms and say gravity may be an exception to the Law of Conservation of Energy i.e "gravity may be a regenerative energy". That would have every one up in arms in and of itself but since no one has actually defined gravity in a compreshensive sense, and many great minds have tried, it may be that it is regenerative energy" Perpetual motion on the other hand does not equate to "FREE ENERGY" and to say that one is impossible because the other is impossible is illogical because they are not the same thing (equal).
Perpetual motion is literily motion that goes on forever, the First Law of Motion confirms perpetual motion with this definition.
Perpetual motion take to mean a machine or system that goes on forever yielding a energy output on the other hand is a skew of actual perpetual motion. You have to know which perpetual motion some one is trying to refer to. But mostly they refer to the latter. The proper way to identify the latter is perpetual motion machine it indicate you are refering to perpetual work output an not to perpetual motion. Since to say perpetual motion is impossible is to try and over through the First Law of Motion. If perpetual motion were impossible the First Law of Motion is wrong because an object in motion would not stay in motion at a constant velocity even though zero net force was applied to it.
Science, however, claims if perpetual motion (making no distinction between actual perpetual motion (First Law of Motion) and perpetual work output) were possible the laws of science would have to be wrong and much of what we know would have to be altered and not just science but mathematics too. In part science has disregarded its own Laws specifically the First Law of Motion in making that statement. The statement is demonstrately false and goes to bias in an effort to cover that fact up.
Perpetual work output refers to a perpetual motion machine giving more energy out than is applied by some fuel source or energy source that is intentionally applied by act of man. The justification to the statement comes in the assumption that perpetual work output would constitute "FREE ENERGY" or literly "energy from nothing" which of course is a violation to the Law of Conservation of Energy. By disregarding any other possible means of developing a perpetual work output science takes a narrow minded point of view, thus biased, and rejects any plausible observance to the contrary with out fair and just consideration. In other words science is no longer objectivly seeking the truth.
Are there objections to this statement? I am sure there will be but if you are intent on making an objection I would like to point out that it shows your bias on the issue. I would suggest you consider what I say and give it fair and open thought prior to making objection. I'll make this last statement I have spent 14 months trying to prove perpetual motion (work output) is impossible, because up unitl April 2007 that was my stance as well. I can say this, it is impossible to prove it is impossible to get perpetual motion (work output) but it can be proven that it is possible and not violate one single law of science as they are written. I challenge anyone wishing to take on the defense of the statement that perpetual motion is impossible to prove that statement with scientific law. Warning I have 14 months of intensive study head start on you and a science education prior to that, and it was the science education that had me immediately defending the notion that perpetual motion (work output) was impossible. I now am forced by proper ethics in science to state other wise based on sound and reproducable observations. Care to challenge me? Or do you care to start listening to what I am saying and look at the evidence with an open mind?
An add in as food for thought
You can extract work from gravity (hydro-electric plant) but entropy will always increase overall.
Isn't gravitational potential simply an intermediate form of energy in that scenario, with the energy itself originating from the Sun?
Yes the energy driving the cycle of water used by a hydro-electric plant comes from the sun evaporating water that then falls at elevation and flows down hill by gravity. The energy from the sun provides the perpetual cycle, gravity provides the energy transference into usable energy output and the use of that energy output is the work done by the perpetual cycle. Take away the sun and the perpetual cycle stops.
To the comment made by matrix, if you extract energy from gravity does gravity diminish? The law of conservation of energy would tend to say yes. However gravity is a constant so if diminished how can it be a constant? If not diminished how can you extract energy from gravity with out gravity reproducing energy so it remains constant? I'll point to the gravity assist technique used by NASA to propel space craft using the force of gravity as an example of energy transference to an object outside a closed system where the gravity of the closed system remains constant after the transference of energy.