The most commonly known thing about homeopathy is the idea that water can 'remember' other substances it's been in contact with, ranging anywhere from cobalt to arsenic. As you were no doubt taught in your first few science lessons water is made up of three atoms bonded covalently, two hydrogen and one oxygen. This relatively simple molecule is overcomplicated and mystified beyond belief by homeopaths who attempt to make all sorts of ridiculous claims about it. Consider this little gem written by a doctor for the Lifecare Advanced Homeo Clinic:
H2O is a particularly interesting molecule in the sense that it makes up the only substance on the planet that can exist in three states – solid, liquid and gas. Water has the highest surface tension of all liquids, it’s the most powerful solvent on Earth and has the remarkable ability to rise up through the trunks of massive trees, defying gravity and immense atmospheric pressure in the process.Normally I'd be banging my head against the desk in futile rage but this time I'm delighted - we've got some very interesting changes in physics to apply to our little thought experiment. First of all, the only substance which can change into all three states is water - no more solid or liquid xenon for use in research at Fermilab or relatively easily produced solid nitrogen in our new universe. Since water is now the loosely defined 'most powerful solvent on Earth' it will remove spots, thin paint and strip nail polish more effectively than our currently used alternatives.
Even more bizarrely we've now got water molecules which defy gravity - like all other molecules water will move upwards if the magnitude of a force in this direction exceeds the force exerted downwards by its weight. But for now let's go with the wording of the extract and say that water now defies gravity. Which begs the question, just how much would it resist the force of its own weight? It would either drift off into space leaving a barren ball of rock in its wake or the rising seas and oceans would leave a constant mist or mass of water around us. If this progressed into becoming constant cloud cover we might run into serious problems providing plants with enough photons to photosynthesise as they should do - a decrease in the amount of crops we can grow could have a disasterous impact on food supplies in an already overpopulated world. This is before we've even considered the climate changes which would occur if the oceans and their currents ceased to exist in their current form.
As for the immense atmospheric pressure it's supposed to resist I can give you the choice of two options: we're either living under a huge amount of atmospheric pressure exceeding our current pressure or hardly anywhere else exceeds the atmospheric pressure on our planet. The first option would lead to us being crushed flat under the pressure or developing an extraordinarily tough skeletal structure (which would be difficult to maintain with the decrease of solar radiation we mentioned earlier - less vitamin D). The second option would mean that stars lacked enough pressure to ignite nuclear fusion, leaving our solar system and countless others without enough electromagnetic radiation to sustain any life. The universe would be a dark and completely desolate wasteland full of debris, no life to be seen.
From this small selection of errors we've managed to make previously benign quackery turn into the possible death of life all on Earth. Pseudoscience is great fun, isn't it?
For the sake of our health and physics as we know it, I'm extremely thankful homeopathy is a complete sham. I get the idea that homeopaths haven't fully considered the possible consequences of their flights of fancy - we've already gone into why it would signal impending doom, but we'd also have many objects remembering pathogens and poisonous substances which may or may not cause serious illnesses depending on your mood. They're well-meaning, I'm sure, but ultimately fraudulent and potentially dangerous.
Expect more entries on the universe according to pseudoscience in the near future - I'm having a lot of fun playing around with reality and ignoring scientific evidence.