Artificial foods — Could you make them? And would they compare to their "organic" counterpart?
No, it is not currently possible to create whole foods (like an apple) (as opposed to processed foods, like sugar or vinegar*) from their component chemicals.  The reason is simple:  All whole foods are composed of tissues, which are in turn made of cells, and we aren't close to being able to synthesize cells, especially eukaryotic cells, from their component chemicals. Their structures are far too complex. [https://en.wikipedia.org/wiki/Artificial_cell]
*In this sense I would also consider honey a processed food, though it is processed by bees instead of humans.
The closest we can come to creating artificial tissues is to clone existing cells; but that wasn't your question.
So then the question becomes whether we could fully characterize all the components of a whole food (again, let's use the apple as an example), and create a mixture containing all those components—and whether, in so doing, we would have something nutritionally equivalent.
The answer to that is not known, and I would say the burden of proof lies with those who wish to claim it would be nutritionally equivalent.  Even if we could characterize every possible micronutrient in an apple, we still wouldn't necessarily know, much less be able to recreate, the states in which they exist (in particular, their states of association with other compounds) within the apple.
Certainly there is a difference between a micronutrient that is complexed with other micronutrients, and then contained within a structure and then contained within another structure, and one that is mixed within a paste and thus complexed with compunds with which it might not be naturally associated in the intact apple. Of course, we do &quot;paste&quot; the apple ourselves when we chew it, but that process likely does not lead directly to the type of paste you would have if you tried simply mixing all the apple's constituent compounds together.
And it's not just how we directly would react to the difference.  There's also how the organisms of our microbiome would react.  It's certainly possible that consuming intact apples would favor one species of microorganism, while consuming synthetic apple paste would favor another, thus leading to changes in the balance of our microbiome.
Then we have to combine all the above uncertainty with the enormous added uncertainty that exists surrounding human physiology and nutrition.