One problem with epiphenomenalism is this: if conscious experiences can have
no effect on anything whatsoever, then we should never know about or be able
to speak about them, since this would mean they had had an effect. Another dif-
ficulty is that if mind is a by-product or side-effect of the physical world but is
not actually physical itself, then epiphenomenalism is really a kind of dualism.
Nevertheless, scientific or methodological behaviourism is built on one version of
this idea: the idea that mental states exist, but do not have effects that can be (or
need to be) investigated scientifically.
Trying to avoid the extremes of materialism and idealism without falling into
dualism are various kinds of ‘neutral monism’, which claim that the world is all
made of one kind of stuff, but a stuff that cannot be classified as either mental
or physical. William James started with ‘the supposition that there is only one
primal stuff or material in the world, a stuff of which everything is composed’
(1904, p. 477). To avoid reducing mind to matter or doing away with matter alto-
gether, he suggested that instead of thinking of a world of physical objects, we
should think of a world of possible and actual sense-data, in which the present is
made of ‘pure experience’, before consciousness and content get retrospectively
split off from each other. ‘A science of the relations of mind and brain must show
how the elementary ingredients of the former correspond to the elementary
functions of the latter’ (1890, i, p. 28), he said, but he did not underestimate the
difficulty of this task. The difficulty of developing a detailed account of the neu-
tral stuff which the theory depends on, and the fact that it ‘attracts neither those
who think the mental is a basic feature of reality, nor those who dream of the
desert landscape of physics’ (Ludwig, 2002, p. 21), together make it a generally
unpopular view.
Another way of trying to get around the problem is panpsychism, the view that all
material things have awareness or mental properties, however primitive. If mate-
rialism is the thesis, Chalmers says, and dualism is the antithesis, panpsychism
is the synthesis (Chalmers, 2017). In some versions everything in the universe is
conscious, including electrons, clouds, rivers, and cockroaches. This ‘pure’ pan-
psychism (Strawson, 2006, 2008) can be thought of as like carrying out a ‘global
replace’ on the usual definition of physical things (mass and energy) as being
non-experiential and defining them as being experiential as well (Strawson,
2011, p. 271). This leaves in place everything currently explained by physics. In
other versions, experience is another fundamental quality, alongside matter and
energy, to be added to our understanding of the world.
Panpsychism raises difficult questions. Is a stone aware? If so, is each of its mole-
cules also separately aware? Are the loose bits on the edge of the stone separately
aware when they are just hanging on or only when they are completely knocked
off? What would it mean for something as simple as an electron to have mental
attributes? Despite these difficulties, some popular recent theories of conscious-
ness, including Integrated Information Theory (Chapter 5), are considered to be
forms of panpsychism (Tononi and Koch, 2015).
Given the difficulty of uniting the world, it is not surprising that dualism
remains enduringly popular despite its problems. Given the difficulties that
arise as soon as we even try to talk about mind and matter, it is also unsurpris-
ing that the whole field of psychology has had such trouble with the concept
of consciousness.
