Complexes are psychic contents which are outside the control of the conscious mind. They have been split off from consciousness and lead a separate existence in the unconscious, being at all times ready to hinder or to reinforce the conscious intentions.

Disease is somatic; the suffering from it, psychic.

Every natural scientist who thinks with any degree of consistency at all will, I think, come to the view that all those capacities that we understand by the phrase psychic activities (Seelenthiitigkeiten) are but functions of the brain substance; or, to express myself a bit crudely here, that thoughts stand in the same relation to the brain as gall does to the liver or urine to the kidneys. To assume a soul that makes use of the brain as an instrument with which it can work as it pleases is pure nonsense; we would then be forced to assume a special soul for every function of the body as well.

I think that in order to achieve progress in the study of language and human cognitive faculties in general it is necessary first to establish 'psychic distance' from the 'mental facts' to which Köhler referred, and then to explore the possibilities for developing explanatory theories... We must recognize that even the most familiar phenomena require explanation and that we have no privileged access to the underlying mechanisms, no more so than in physiology or physics.

In clinical investigation the sick individual is at the centre of the picture. The physician must have a deep interest in his patient’s economic and social structure as well as in his physical and psychic state. If attention is not paid to the diagnosis of the person the clinical investigator is apt to fail in studies of the patient’s disease. Without a consideration of the patient as a human being it would have been difficult to have fed patients daily large amounts of liver.

In the dog two conditions were found to produce pathological disturbances by functional interference, namely, an unusually acute clashing of the excitatory and inhibitory processes, and the influence of strong and extraordinary stimuli. In man precisely similar conditions constitute the usual causes of nervous and psychic disturbances. Different conditions productive of extreme excitation, such as intense grief or bitter insults, often lead, when the natural reactions are inhibited by the necessary restraint, to profound and prolonged loss of balance in nervous and psychic activity.

It [mathematics] is in the inner world of pure thought, where all entia dwell, where is every type of order and manner of correlation and variety of relationship, it is in this infinite ensemble of eternal verities whence, if there be one cosmos or many of them, each derives its character and mode of being,—it is there that the spirit of mathesis has its home and its life.
Is it a restricted home, a narrow life, static and cold and grey with logic, without artistic interest, devoid of emotion and mood and sentiment? That world, it is true, is not a world of solar light, not clad in the colours that liven and glorify the things of sense, but it is an illuminated world, and over it all and everywhere throughout are hues and tints transcending sense, painted there by radiant pencils of psychic light, the light in which it lies. It is a silent world, and, nevertheless, in respect to the highest principle of art—the interpenetration of content and form, the perfect fusion of mode and meaning—it even surpasses music. In a sense, it is a static world, but so, too, are the worlds of the sculptor and the architect. The figures, however, which reason constructs and the mathematic vision beholds, transcend the temple and the statue, alike in simplicity and in intricacy, in delicacy and in grace, in symmetry and in poise. Not only are this home and this life thus rich in aesthetic interests, really controlled and sustained by motives of a sublimed and supersensuous art, but the religious aspiration, too, finds there, especially in the beautiful doctrine of invariants, the most perfect symbols of what it seeks—the changeless in the midst of change, abiding things hi a world of flux, configurations that remain the same despite the swirl and stress of countless hosts of curious transformations.

Man’s unconscious… contains all the patterns of life and behaviour inherited from his ancestors, so that every human child, prior to consciousness, is possessed of a potential system of adapted psychic functioning.

One of the branches of literature—science fiction is … aiming at disorientation, at psychic dislocation.

Phony psychics like Uri Geller have had particular success in bamboozling scientists with ordinary stage magic, because only scientists are arrogant enough to think that they always observe with rigorous and objective scrutiny, and therefore could never be so fooled–while ordinary mortals know perfectly well that good performers can always find a way to trick people.

The teens are emotionally unstable and pathic. It is a natural impulse to experience hot and perfervid psychic states, and it is characterized by emotionalism. We see here the instability and fluctuations now so characteristic. The emotions develop by contrast and reaction into the opposite.

The world is full of signals that we don’t perceive. Tiny creatures live in a different world of unfamiliar forces. Many animals of our scale greatly exceed our range of perception for sensations familiar to us ... What an imperceptive lot we are. Surrounded by so much, so fascinating and so real, that we do not see (hear, smell, touch, taste) in nature, yet so gullible and so seduced by claims for novel power that we mistake the tricks of mediocre magicians for glimpses of a psychic world beyond our ken. The paranormal may be a fantasy; it is certainly a haven for charlatans. But ‘parahuman’ powers of perception lie all about us in birds, bees, and bacteria.

To stop short in any research that bids fair to widen the gates of knowledge, to recoil from fear of difficulty or adverse criticism, is to bring reproach on science. There is nothing for the investigator to do but go straight on, 'to explore up and down, inch by inch, with the taper his reason;' to follow the light wherever it may lead, even should it at times resemble a will-o'-the-wisp.
Referring to his interest in psychical (spiritual) research.

We only have to look around us to see how complexity ... and psychic “temperature” are still rising: and rising no longer on the scale of the individual but now on that of the planet. This indication is so familiar to us that we cannot but recognize the objective, experiential, reality of a directionally controlled transformation of the Noosphere “as a whole.”

Without some idea of oxidation processes, of the chemical structure of food, and of the chemical reactions in digestion, visceral behavior is a blank. And without some understanding of visceral behavior, psychic behavior is up in the air.