I am arguing that there is awareness - which we can’t test for - and cognitive functions - memory, ability to do math, ability to read the emotions of others, ability to count, and millions of other active functions - which we can test for.
We cannot go up to a new species found in the amazon and measure its consciousness. We can find out how it responds to stimuli. Plants respond to stimuli, for example. Plants take measures in response to threats and they communicate about threats to other plants, not just intraspecies. Plants seem to remember and learn. But are they conscious? Can we take out our consciousness meter and say - look it’s showing 23 globs of awareness.
Even up into the 60s it was taboo in science to talk about animals being aware. Did we discover a consciousness detection device? No. The change happened because the old default got worn down.
We are getting better inside our own species. We can look at MRIs and find certain kinds of activities that in other people show they are aware. So, people with locked in syndrome may get discovered to be conscious. But this doesn’t work with ‘species’ or things not like us. And our bias has always been to assume that we are the measure of consciousness. If it is like us, perhaps it is conscious. Hence the long delay in science to stop considering animals mere machines without consciousness. (animists and animal trainers and pet owners knowing that was silly for a long time before science shifted on the issue)
So, my end sentence does not contradict what went before. We can see all sorts of behavior in plants that in humans we consider part of signs that they are conscious, but science has tended to assume the opposite and given their is no electric wand we can wave over a plant and say it has 12 glob of consciousness right now, the bias in science remains. But there has been a trend to challenge this and it is becoming less taboo to consider that plants might be aware and thinking, rather than merely doing things mechanically, with no consciousness at all. Generally they, like animals before them, are viewed as chemical machines, with no consciousness, in science. But the default, the bias is being challenged.
Science is conservative. We shouldn’t believe anything until it is proven with repeatable evidence and isolated causes - limit the variables.
But that assumption, that it’s best for us to live with only those beliefs, has not been demonstrated.