Neuroscientists tell us that time, space, and perceived matter are all constructs of the brain.
As physics is about the exploration of these, is physics really a branch of psychology ? If not, what is the difference ?
Neuroscientists tell us that time, space, and perceived matter are all constructs of the brain.
As physics is about the exploration of these, is physics really a branch of psychology ? If not, what is the difference ?
There's a difference between the ordinary mental representations of space, time and matter everyone has and the mathematical representations of the physicists. The physicists representations are abstract, formal constructs that are posited to explain physical phenomena, while one's mental representation is given in experience, and not posited as an explanation of anything. So it would be a mistake to conflate the two.
Also importantly, the physicist's representations are not an individual's representation, they have collective use: physical theories are not tested against one's subjective perception of positions, but against inter-subjective measurements, generally carried out by teams of scientists, often relying on elaborated measuring apparatus rather than direct perception (distances can be measured with lasers or sonars, durations with all kinds of clocks), converted to numbers (data models) that anyone in principle could check, very often by reading numbers on a computer screen. Neuroscience has nothing to say about these measurements of distances and durations because they do not really depend on anyone's subjective experience of space and time.
Finally, neuroscience cannot really cast sceptical doubt on the results of physics because it relies on them, to some extent: part of neuroscience rests on an understanding of chemistry, which itself rests on an understanding of physics, and the apparatus of neuroscience are based on physical knowledge too. So if neuroscience were to show that the content of physics was an illusion, it would undermine its own basis.
All this does not mean that one cannot be an anti-realist about the content of physics, but it takes more than neuroscience to argue for this.
I would suggest that math is a branch of psychology. From an Intuitionist perspective on math, it is the study of what abstract intuitions most humans naturally share. Those intuitions are clearly ideas, and therefore the province of psychology. The question as to what ideas are mathematical is not about 'absoluteness' or some other way of being true, because ultimately there is nothing real that they actually describe perfectly. The real question is whether they can be naturally evoked in other humans, largely independent of experience, and therefore used as a basis for a shared explanation.
Physics reduces observations to math, but it is not the physics that is psychological, it is the math. Physics does not actually study the concept of space, it studies what things do in space and what space might do in response. Mathematics studies the concept of space as a manifold and provides physics with the geometry that expresses the theory of relativity.
The empirical and explanative power of advanced physics is simply incredible, and has even provided "us" with Hiroshima, a man on the moon, etc. You might find some people (philosophers?) that claim these miracles are merely ideal, and say nothing about reality itself. But no-one is saying that we can do these things just by studying the brain. Outside one's Cartesian fantasies, I mean.
Our mind categorizes perceptions on two groups:
What you are saying is that things on the second group are also subjective perceptions, and that can be true: several philosophers state that objectivity is not possible, there is only shared subjectivity.
Anyway, the rules of the first group are fuzzy and irregular. Psychology is the discipline that takes them as the object of study. But it is difficult to assess, due to the high level of subjectivity involved.
On the contrary, the discipline that studies the second group's principles is essentially physics. Physics have shown that several physical behaviors are predictable, regular and stable. This is relatively easier to address, since we can be objective (or at least, share congruent subjectivities) about it.
No, the second group has nothing to do with psychology. Moreover, with philosophy, a set of objects on the first group that allow an intermediate level of objectivity.
Is it biology that cats fall out of trees at 32 ft/sec/sec? No. Why not? Because there is no biological content. The fact is easily subsumed under a fact from physics. Is it sociological that when you drop acid on a crowd, people cry out in pain? No. Why not? Because the facts of acidity are chemical, and the reaction to pain that causes you to cry out is a matter of individual psychology.
But what do we mean by such assertions. We consider things like acidity to lie within the realm of chemistry, but we consider most facts about protons to lie more properly within physics. And acidity has been part of chemistry since before we knew what protons were. Why did it not spontaneously become physics? Why did chemistry come out of alchemy instead of all this material just vanishing under the umbrella of physics when the theoretical basis of alchemy failed?
One reasonable answer is that the different domains of science handle things that are emergent properties of other domains of science, as elaborated here
By that criterion mere experience is one thing, and psychology studies emergent properties of experience. Your particular sadness is a fact of experience, but it is not a fact of psychology. Only patterns of thought which emerge out of experience can be considered psychological. That watching my dog struggle causes me to be sad qualifies as a psychological observation. That I see red light when there is a red light shining in my eye is hardly psychological phenomenon. That I can see yellow light when you shine a green and a red light in my eye is not even a psychological phenomenon, it is a biological one. And it is not even really a physical one -- it does not fit the normal theory of color in physics.
The idea that I can choose a given wavelength of light that will be perceived as yellow has some physical quality but may not even qualify. The fact that in general different wavelengths of light are perceived as different colors is clearly physics. The breadth of the pattern matters, as it determines where we pull away from the underlying cause and consider an explanation relevant to the question at hand, rather than an overly specific failure to answer it.
The emergence in physics, for physics to be physics, requires separation from individual experience, in a way that the patterns of psychology do not always have to. There can be a psychological fact that applies to only a single individual. But if you had a physical fact that applied only when a given person ran the experiment, it would be rejected as a theory of physics.
To attempt to reduce everything to physics, or to psychology, or even to human experience ignores the reasons we have these concepts. Human experience involves things that are emergent from biology, and things that are emergent from psychology in the same way that biology contains things that are emergent from chemistry and therefore from physics. There is at best a network of loops here, and no most basic set of facts.