The view — when we stare up at a night sky (with a minimum of light pollution) with our naked eyes — is pretty spectacular. And that’s just from our obstructed view in the cheap seats.
Our view of the cosmos is obstructed though we forget that fact. Our eyes can only see visible light (and, to a degree, black light). But we can’t see light in the x-ray spectrum. Or gamma rays. Or infra red or in the radio spectrum. Imagine though if human eyes could see the whole spectrum of light. Imagine if we could hear what dogs and cats hear or have a shark’s nose for blood.
In other words — humans perceive a lot less than we think we do. And that’s just in the physical world.
Hell, we don’t even know what thoughts are — other than the product of electricity flowing through our brains. If we’re so uncertain where our own thoughts come from, how can we say that other creatures with similar brain structures don’t experience the same kinds of thoughts? For that matter, can we even say that creatures without our brain structures don’t experience thoughts.
Slime molds, for instance, lack any kind of nervous system whatsoever — and yet yellow slime molds are known to solve mazes, make decisions and learn. If they’re aware that food is nearby, they’ll hunt for it (intelligently). If you put fire or excessive heat in their path, they avoid it — like they know without having to experience it that the fire or heat will cause them harm.
Scientists being scientists, they want proof that other creatures experience literal thought. An ethicist would tell them to open their eyes and observe the natural world a little more closely. One doesn’t necessarily need a measuring tool to be assured something quantitative just happened. When my cat looks me dead in the eye, I know she wants something. She knows she wants something. She’s doing everything she can to communicate what she wants to me — staring at me, staring at her food bowl; cats, incidentally, are one of the few creatures that can follow a gaze to a remote object.
I have no data other than the anecdotal to prove my case — but if I open the door for my cat, she won’t take her eyes from me. That was not what she wanted. If I put fresh food in her dish however, she’ll eat (she’s a finicky cat, remember, not a dog who’d eat anything). If I don’t do what she wants and walk away, she’ll come find me. Mission not accomplished. The human wasn’t listening.