>Are you certain this is correct? An individual with a genetic mutation does not necessarily pass it down to its offspring, even if it was beneficial, in my understanding. So there is a probability p of passing it down and 1-p of not doing so.

That value for p is still going to be considerably greater for the gene to be passed on than the probability of that gene arising again randomly through mutation though. Consider the example of eye colour for example, chances are two brown-eyed parents are going to have brown-eyed children too - certainly a greater probability than a random mutation will intervene to make their eyes purple.

>Depends which subarea of evolution. No actual speciation based on random mutation has ever been observed (let alone ones predicted by evolution) as far as I'm aware.

There have been empirical studies of species separating and the mosquitoes on the London Underground are a good example, surface-dwelling mosquitoes cannot interbreed with those from the tunnels. At any rate it's actually quite a difficult thing to study since we're not looking at a binary situation of 'they have gene x now and therefore they're a separate species', that's not how evolution works and I don't think any biologist would claim this to be the case. At the end of the day species are human classifications made based on scientific observation rather than perfect formal categories, we define a species to be that which cannot interbreed with another and produce fertile offspring but that's our classification not nature's - species diverge gradually after taking many different evolutionary paths rather than there being a binary instant they're separate from each-other. The classification of species can only ever be so good because it's attempting to draw a fixed line on a moving canvas.

I think when arguing against the theory of evolution it's tempting to make arguments along the lines that each species is assigned some kind of intangible Platonic form towards which evolution must work but this isn't the case at all, there's no law of nature that says one species has to take x form and another must take y form. There's no Platonic cat which makes a cat a cat rather than a dog or a goldfish, a cat is merely one of the many possible organisms that can fill the ecological niche that cats occupy; and we classify them with our imperfect system of biological classification. I think it's putting the cart before the horse to essentially say that evolution is a flawed theory because our system of categorising species doesn't have the resolution to capture the exact moment species diverge from each-other.

>Micro-evolution or expression of previously not-expressed but already present genes is a different topic, and not something I have issues with.

Micro-evolution versus macro-evolution is a bit of an old canard in my opinion, the idea that they're separate processes rather than a continuum of the same process doesn't really exist outside of creationism which in my opinion is a much more difficult theory of our origins to argue than evolution. I spent some of my early life as a creationist so I'm not unfamiliar with its nuances, but personally I'm yet to hear a creationist argument that is particularly compelling to people who aren't already invested in the existence of a Creator rather than approaching the subject neutrally.

> All I say is evolution is at best insufficient to explain us. And we haven't even touched consciousness.

Consciousness is definitely a much more interesting problem in my opinion, and there's definitely no good theories of consciousness yet as far as I'm concerned. I think the notion of qualia in particular poses a lot of difficulties for a purely materialistic understanding of consciousness for example.