If a tree falls in the middle of a forest and no one is around to hear it, does it make a sound? According to philosophy, it makes no sound because there is no one to hear it, but according to science, it makes a sound because of the vibrations of the tree hitting the earth (probably a lot more complex, but that is off topic).
Well, if you don the Immanuel Kant mask next time at the massive Halloween party over at B-n-R, you surely won't need to sample the LSD at the Retro-Hippie section. Much contemporary paraphrasing of Kant in synopsis below, biased toward only covering what might seem relevant here (appearances):
Material bodies are things exhibited outside themselves, which is the dead giveaway that they are the representations of a cognitive system rather than how they would exist in themselves. Examine any substrate of a body, and the components are still observed, measured, or described outside themselves (how they exist to the observer or the particular symbolic / interpretative process employed).
Human experience is things (that are unknowable as they exist in themselves) being given a place to be empirically real, connected by extrinsic relations. Where the influences of these things are received somehow and conformed to a world-depicting system where unconditioned things otherwise existing by themselves are ironically made dependent upon each other (integrated by transcendental conceptual rules of causation, time, space, relation, quantity, etc.).
You have freedom, because you are a two-aspect entity, one of the partly knowable kind of things in themselves (minds). You have a "phenomenal" aspect that belongs to a deterministic, conditioned natural world where you are embodied, have no free will, and are intersubjectively represented with other human minds (as bodies also). Your "noumenal" aspect belongs to an internal order that has its own laws, separate from the natural side, and thus granting you freedom in decision-making, which always gets converted into the natural order on the other side (sort of disguised as deterministic).
Okay, if you ever start consuming Kant, you now know why you shouldn't add the LSD at the retro-60s display at that party. Or anything else (joining the 27- Club is overrated).