688 TRANSACTIONS OF SUB-SECTION TI. 
investigation of the contents of consciousness is imageless thought. The pro- 
positions were concerned with mathematical, grammatical, historical, and other 
conceptions, and the subjects were given sufficient time to make a full record. 
The results of their introspection, concerned with 178 acts of thinking, were sub- 
sequently analysed and classified, and were found to yield quite clearly the chief 
conditions which favour or hinder the development of mental images in the 
higher thought processes. 
It seems probable from these results that, under ordinary conditions of 
thinking, mental images would be absent in about 50 per cent. of all cases. 
Vivid mental imagery may hinder or aid the act of thinking, depending on 
whether the image itself or its meaning occupies the focus of consciousness. 
When the meaning of a proposition is readily understood or when it is quite 
familiar, there seems to be no tendency to embody the thought in an image. 
Thought is carried on in these cases entirely by meanings. In many cases the 
consciousness of meaning precedes the full utterance of the statement—the 
initial words carry the whole meaning in themselves. 
The conditions for producing images are easily seen from the following case 
of introspection. Two of the propositions given were (a) if unequals are added 
to unequals the wholes are unequal; (8) if equals are added to equals the 
wholes are equal. These were dictated in the order given, with an interval 
between. With reference to the former one of the subjects said ‘ Doesn’t 
sound probable somehow. Rather a wrench necessary to enable me to realise 
that you have two sets of things to work with. Then I saw that it is a lie 
(sic), as a picture of heaps of plain wooden bricks arose, thus: ’ 
With reference to the second statement he said ‘ Sounds much more reason- 
able. Of course it’s true. No need to fetch the bricks out to prove that one.’ 
And indeed he had no mental image. This striking case is but a clear instance 
of what seems to be general. 
For the experiments show that any kind of struggle or delay in consciousness 
is a favourable condition for arousing a mental image. Conflict or disagreement, 
any attempt to overcome a difficulty of understanding, suspension of judgment, 
doubt, emphasis, all tended to produce mental images in abundance. And all 
of these are instances of struggle or delay. 
The experiments also showed that the contrary set of conditions are un- 
favourable to the production of images. Thorough or immediate understanding, 
an easily grasped conception, ready assent, straightforward or unimpeded 
reasoning, were all cases in which images, as a rule, played no part. Whatever 
promotes the easy or unimpeded flow of thought is unfavourable to the produc- 
tion of mental imagery and vice versd. Just as an electric current has to 
meet a high resistance before it produces light, so thought has to encounter an 
obstacle in order to evoke an image. 
6. The Psychological Foundation of Economics. 
By Rev. P. H. Wicxstrrp, M.A. 
7. Psycho-analysis. By Witt1am Brown, D.Sc. 
In the course of this paper the following topics were discussed :— 
1. Freud’s fundamental views on the nature of consciousness, the precon- 
scious and the unconscious, as set out in the final chapter of the ‘ Traumdeutung.’ 
